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    Posted: 15 Jun 2018 at 7:44pm
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Originally posted by Tonto2 Tonto2 wrote:

ffs killmeknow

LOL
Death - Our community's #1 killer
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Post Options Post Options   Likes (5) Likes(5)   Quote Tonto2 Quote  Post ReplyReply Direct Link To This Post Posted: 14 Jun 2018 at 7:45pm
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ffs killmeknow
slowly going where everyone else has already been
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yes a little simple, but basically correct.. there is more to timing than most think or understand..
Timing.. an internal combustion engine has best timing wher max explosion is reached between 12 and 18 degs ATDC.. this is not the set timing as there are a few milli secs for the spark and flame to cross the chamber.
 All degs are in crank degs..
 Withing that 12/ 18 deg (6 degs) the premium timing will be within +/- 1.5 deg..at a given rpms and engine load. 
Also makes the old school swing on the distributor (anologe 'ECU tuning') tune by ear is BS.
Also the tendency to advance is sort of a myth.. Manufactures tend to be sightly low on advance.. espec as a chamber carbons compression rises, higher compression requires less advance, there for a used engine that is set to max advance curve will be over advanced.
 Knock, an engine knocks well before any audible knock.. ball park 2 to 3 degs..and load at a given rpms will also influence the point of knock...
Then throw in a feel/ audible  'optical illusion' effect..

As an engine is advanced the engine will sound 'stronger' so much so you will believe you can feel it in the back of the seat...going up to the optimal advance at a given rpm and load, power/ economy increases quick, go over that advance, it drops off slow.. but keeps on sounding stronger even into inaudible knock. 
Most would increase advance over advance, and engine 6 months later would die and bad machining or similar would get the blame
Advance when dialing in starts high...just below inaudible knock, power will increase slightly then drop of very quick within 1.5/2 degs... at a given load and rpms.

99% of my stuff was done on old school dizzy "(analog).. initial/ centrifugal/ vacuum advance..
When modern self powered sensors  (knock, O2/ emap/ vaccuum) came along that can be run on old school non ECU engines with affordable data loggers (eg the Innovate II) around 20 yrs ago. dialing in to establish the tuning parameters of an old school engine become a very new ball park most never got their head around.
Modern ECU is exactly the same doing it electronically, thu I do find the modern 'technician' not having a background in the analog dizzy, often doesnt have the background understanding of or the tiny tolerances of timing... same as the old school pre sensor/ data logger old school guys.

I have highlighted "at a given load and rpms."
 simply pushing (use a dizzy as example) a cent curve up doesnt work.. the whole curve.. springs weight etc need to be changed right thru rpm range and full load... then the vacuum advance curve needs to be modified for the higher advance required at a given rpm and load right thru the rpm range, and asload changes so does engine vacuum so the influence of that vacuum for that engine at a given load also needs to be taken into account in the VA curve.

 swing on a dizzy ,old school tune by ear... nah doesn't work, just slow death to the engine..
 And the same applies to dialing in electronically modern ECU engines.
 The big advantage on modern ECU/ injection..injection control is almost instant direct into the camber, unlike a carb that has delay and narrow effective rpm range, and knock /emap/ O2 sensors give far more almost instant adjustment right thru thru rpm and load range.
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Post Options Post Options   Likes (2) Likes(2)   Quote Grasshoppa Quote  Post ReplyReply Direct Link To This Post Posted: 14 Jun 2018 at 9:17am
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Oh come Rozboon, thats just too simple and makes too much senseLOL
Surely it needs a long winded explanation with formulas etc qualifying it haha

I say this tongue in cheek but your closer to the truth than most think
Originally posted by Rozboon Rozboon wrote:

Originally posted by Steps Steps wrote:

I've never been a huge fan of the highest output model of a given block.
For example in the Hondas, the 80, 90, and 100 are all the 1.5L inline 4.
Aside from just revving it a bit more, it would be interesting to know what, beyond an ECU calibration, has been done to get 20 more hp from the 100 over the 80. I always wonder if it just makes for a more highly-strung, slightly less reliable motor.
 A engine of a given volume requires a mixture of a given volume..at a very close  AFR (air fuel ratio). and that proportion of the ratio which is fuel has a given amount of  potential energy stored in it.
 This amount of energry can be increase by raming ( turbo/ blower ) more fuel mixture under pressure  in effect increasing the volume of the engine... but this is not the case here.
By changing cam profiles.. how lomng the inlet is open. how long the inlet and exhaust are open at the same time oine can change the amount of fuel mixture in the chamber , and the compression pressure.. then ( see previous  bofin post on octane , cylinder pressure , time of flame across the cylinder timing and metering (carb or injection)
 These variable therefore change the amount of hp/ torque at any given rpms.
 In saying that , I do not understand the justification huge difference in price between hp models outside simple profit taking..

To be honest I suspect 99% of the motor is the same between the different horsepowers. I would wager a shiny penny that the major difference is the tune loaded on the ECU. Run the 80hp a little fatter, don't advance the timing as much; conversely run the 100hp closer to the knock limit. If they have to be run on 95 octane they're probably already a little bit knock-prone.
I can sit there with my car on a dyno and dial up virtually any power level I want by mashing + and - on a laptop, and I bet you with these motors that are running such similar blocks that's just about all they do.

In fact, because I'm a giant nerd, I went and looked up the US market parts on a Honda 75, 90 and 100, the actual important bits that kinda affect how much power you make (pistons, crankshaft, cams, cylinder head, manifold, injectors) the only difference was the 75 uses a different cam and the 90 has a very slightly different part number for the cylinder head (75 and 100 use the same head). Same gearbox too. Read into it what you will but to my mind all the difference in power output is going to be due to the tune loaded onto the ECU, therefore it's hard to escape the appearance that they're all virtually the same motor and the 100 is just being run harder.
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Post Options Post Options   Likes (0) Likes(0)   Quote Rozboon Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jun 2018 at 9:37pm
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Originally posted by Steps Steps wrote:

I've never been a huge fan of the highest output model of a given block.
For example in the Hondas, the 80, 90, and 100 are all the 1.5L inline 4.
Aside from just revving it a bit more, it would be interesting to know what, beyond an ECU calibration, has been done to get 20 more hp from the 100 over the 80. I always wonder if it just makes for a more highly-strung, slightly less reliable motor.
 A engine of a given volume requires a mixture of a given volume..at a very close  AFR (air fuel ratio). and that proportion of the ratio which is fuel has a given amount of  potential energy stored in it.
 This amount of energry can be increase by raming ( turbo/ blower ) more fuel mixture under pressure  in effect increasing the volume of the engine... but this is not the case here.
By changing cam profiles.. how lomng the inlet is open. how long the inlet and exhaust are open at the same time oine can change the amount of fuel mixture in the chamber , and the compression pressure.. then ( see previous  bofin post on octane , cylinder pressure , time of flame across the cylinder timing and metering (carb or injection)
 These variable therefore change the amount of hp/ torque at any given rpms.
 In saying that , I do not understand the justification huge difference in price between hp models outside simple profit taking..

To be honest I suspect 99% of the motor is the same between the different horsepowers. I would wager a shiny penny that the major difference is the tune loaded on the ECU. Run the 80hp a little fatter, don't advance the timing as much; conversely run the 100hp closer to the knock limit. If they have to be run on 95 octane they're probably already a little bit knock-prone.
I can sit there with my car on a dyno and dial up virtually any power level I want by mashing + and - on a laptop, and I bet you with these motors that are running such similar blocks that's just about all they do.

In fact, because I'm a giant nerd, I went and looked up the US market parts on a Honda 75, 90 and 100, the actual important bits that kinda affect how much power you make (pistons, crankshaft, cams, cylinder head, manifold, injectors) the only difference was the 75 uses a different cam and the 90 has a very slightly different part number for the cylinder head (75 and 100 use the same head). Same gearbox too. Read into it what you will but to my mind all the difference in power output is going to be due to the tune loaded onto the ECU, therefore it's hard to escape the appearance that they're all virtually the same motor and the 100 is just being run harder.
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jun 2018 at 6:28pm
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The Honda and Suzuki fuel economy are both about the same at the end of a long day - given the Suzuki is a larger displacement its economy is awesome low down but uses more at high RPM

General note here: to compare 2 engines 
1/must be on the same boat loaded the same... can check that one off.Wink
 2/ Both engines need to be installed at correct heights..
3/ At WoT ideally both should reach max rpms , flat water , best trim at the same or close to the same point... ie if 1 brand is say 4500 to 5500  and max rpms is 1/2 way 5000 rpms.. the other engine needs to also be propped (pitch) at similar position between min and max
4/ The prop slip should also be very similar % @ WoT and @ cruise (cupping and diameter)
5/ Both should be Alloy or Stainless, thu a boat under 1000kg fully loaded, the difference is smaller than a larger boat.
5/ Permatrims create a lot of drag..effect extra weight to the boat... A well powered boat will not need a permatrim, a min or under powered a prop with more rake top lever the bow down
 Therefore the Suzi with the permatrim assuming rpms/ install height etc all correct, the permatrim will knock of a few HP.. reduce in effect the engine size.
6/ Any ecomont numbers need to be taken at the same speeds on both engines...The larger engine will cruise faster easier...Ball park 90 to 115hp will give a good 10 to 15% better economy than the 90 hp cruise speed..and will have fa bettwereconomy at faster cruise speeds.

Yes the more hp will mean less "working" less throttle required, less rpms... 
 A quick check to see how well both engines are set up, the weight numbers should be fairly close +/- 50ish kg

34 knots (115hp?)  1443kg
 vs 27 knots (90hp?) 1617 kg
  I would put a loaded 5.5 surtes around the 1100kg mark at a estimate, therefore a well set up engine height install and correct diameter/ cupping  (slip) and so long as both are anywhere in the manufacturer's WoT rpm range.
115 hp should hit around 38 knt  well powered
 And the 90hp 33 knt..a little under powered.

 There is a lot still to be gained on both the engines..

I would definitely recommend more HP though and my vote goes the the SUZUKI 115
 Yep
 Even with engines not well setup that extra hp at the prop still shows a huge difference... performance/ economy everything...



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I have replaced an older Honda 90 on my Surtees 5.5 with a Suzuki 115.  both four strokes.

The Honda and Suzuki fuel economy are both about the same at the end of a long day - given the Suzuki is a larger displacement its economy is awesome low down but uses more at high RPM

The Honda - being a carb'd version is way louder, I cant believe how quiet the Suzuki is.

Honda had a gull wing on the back - which made a superb difference to performance.  It was propped correctly stainless.

The Suzuki had a standard prop but a permatrim and the boat handles way way better in a sea - rides like a longer boat.

The large Suzuki pushes the boat much better - its not that the Honda was working "to hard" or anything like that its just the bigger Suzuki just does everything a little easier and goes quite faster - 34 knots vs 27 knots  But fuel economy is the same.

I had to strengthen the outboard pod and modify quite a few things to accommodate the larger heavier outboard - as my Surtee's 5.5 is an older model it needed some tweaking to get it right.  Not a huge deal once we worked out what needed to be down.  I did not think the extra 20 or 30kg would be such a big deal but I defiantly noticed a  difference in boat at rest with the flooding keel. 

Mate has Mercs - not the new ones but mid 2008's I think and he has to fix something every other trip - lucky he has twins else he wouldnt get home.  The new mercs do look the goods but.  

If I was re-powering again, I would have no worries running a Honda, a good reliable and cheap to run (a lot quieter and better fuel economy then my carb'd being injected to)

I would definitely recommend more HP though and my vote goes the the SUZUKI 115
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jun 2018 at 9:28am
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Regarding the topic, stuff a 100hp Honda in my eyes. the 95 octane would throw me off just because of the extra 15cents a litre.
 So setting the record right here.
 I mentioned before about higheer the octane the lower the SG (persesific gravity)  in rather crude terms . there is less energy stored per L but more energy per weight.
 Now keep in mind we purchase our fuel by volume.. not weight.
When one uses the correct octane fuel for the engine design (cam/ cyclinder pressure /timing/ metering etc) the end result is the $ per distance is very no matter what the cost per L is on the pump.

The exception is where fuels have been 'watered down' with alcohol, be it 91/ 95, 98. In this case the SG becomes even lower.. even less power per L. This applies to most cars as well..
 Basically the cheaper alcohol fuels, even correct octane, thu cheaper on the pump the $ per distance is more expensive

I think you will find most outboards recommend not to use (cheaper) alcohol bases fuels.. so check you manuals.

If you read between the lines of the above.. start doing a few sums, I think you will find if we brought our fuel by the weight, not by the volume, we would get far better value for money and far less be ripped off.

The number ppl who over the yrs call in the workshop, in particular elderly and young complain about their 95/ 98 octane engine doesn't perform and goes thru a lot fuel, ask what they put in , and its cheaper low octane...
 They come back a few weeks later  to say a tank lasts a LOT longer  and power up hills etc is exceptional.

Following is a personal opinion on higher octane in outboards.
 higher octane is more volatile, therefore can degrade the octane rating faster over time... If use a couple times a yr, and always have a full tank, may not be a good idea.. If use couple times a month or more not an issue.
 Thu keeping tank low after a trip, fill up on the way to the 'ramp' with fresh gas is best practice be it a regular or occasional use for marine engines, occasional vintage, classic , hot rod type vehicles.


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Post Options Post Options   Likes (1) Likes(1)   Quote smudge Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jun 2018 at 8:17am
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I agree, this thread isn't here for picking people apart, that can only be counter productive. Back to talking about Honda 100's please.Steps' input is welcomed as is everyone else's opinion.


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Originally posted by JustAnotherSpearo JustAnotherSpearo wrote:

Some of you guys who criticizes others inputs are part of the reason I can't be bothered putting input in half the time and often just end up reading. The more often do you it the more people you drive must away.. I can't be the only one.. 

And I'm about as far from a mechanic as possible. However I have spent a heck of a lot of hours onboard small boats and driving them in some seriously snotty conditions this summer has been great fun playing with the 7m hardtops coming back in from out wide when its chopped up and blowing 20knots + and that comes down to experience and understanding the local water movements. I know for a fact I can drive the boats im used to considerably better than most. I'm not a boat operator by trade. I know our outboards in and out, and I know what the common faults with them and am yet to have to call the guardian angles for a tow home and have had many oopsies that required some thinking to get home.
It only takes one look at Steps commander to understand that the man looks after his equipment and uses it a lot. You'd have to be a fool to disregard and take the mickey mouse out of years of experience, time is something we all are limited with. Learn lessons from others and apply common sense to what they say to figure out how reliable it is.

Regarding the topic, stuff a 100hp Honda in my eyes. the 95 octane would throw me off just because of the extra 15cents a litre. Weight difference isn't a real matter in the grand scheme of things. Servicing is an issue, but also can be a bit of a scam, lets be real your average joe isn't likely to encounter problems during the warranty period.. 
but it is piece of mind that cons us all into it. 
4 years with Suzuki, faulty trim switches on the outboard from a poor design with the seal through to the little 25hp 4 stroke not having the robot at the factory connect the throttle cable up correctly forcing it to get stuck at 3000 odd rpm on the first outing. Every outboard can have issues, biggest thing that causes problems is the user and operator with a lack of maintenance and care.

Personally Mercs have had a bad run in our family, black anchors as such. Probably just struck a bad one for the 4 hours we got to use it as a loan motor.  Just thinking about the choices, Merc have developed their 90-115hp range considerably in the last 4 years from where they were. (weight wise and what not) Honda no real developments since we purchased in this hp bracket just whipped out the 100hp outboard, still the same block though.. Back to the point. Mercs have spent time developing and advancing their product, could be a bad thing, could be a great thing. Someone has to be the test pig 
Great post - I value steps contributions - he came out in my boat and suggested a few things that my mechanic hadn't mainly around trailer setup which was really useful.
Re Merc and development - their new products may be great and salesmen will tell you so like everyone else - personally for boats (and aeroplanes!) I prefer to be a few years behind the leading (bleeding) edge and let someone else take a punt and let me know.
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Post Options Post Options   Likes (2) Likes(2)   Quote JustAnotherSpearo Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jun 2018 at 9:34pm
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Some of you guys who criticizes others inputs are part of the reason I can't be bothered putting input in half the time and often just end up reading. The more often do you it the more people you drive must away.. I can't be the only one.. 

And I'm about as far from a mechanic as possible. However I have spent a heck of a lot of hours onboard small boats and driving them in some seriously snotty conditions this summer has been great fun playing with the 7m hardtops coming back in from out wide when its chopped up and blowing 20knots + and that comes down to experience and understanding the local water movements. I know for a fact I can drive the boats im used to considerably better than most. I'm not a boat operator by trade. I know our outboards in and out, and I know what the common faults with them and am yet to have to call the guardian angles for a tow home and have had many oopsies that required some thinking to get home.
It only takes one look at Steps commander to understand that the man looks after his equipment and uses it a lot. You'd have to be a fool to disregard and take the mickey mouse out of years of experience, time is something we all are limited with. Learn lessons from others and apply common sense to what they say to figure out how reliable it is.

Regarding the topic, stuff a 100hp Honda in my eyes. the 95 octane would throw me off just because of the extra 15cents a litre. Weight difference isn't a real matter in the grand scheme of things. Servicing is an issue, but also can be a bit of a scam, lets be real your average joe isn't likely to encounter problems during the warranty period.. 
but it is piece of mind that cons us all into it. 
4 years with Suzuki, faulty trim switches on the outboard from a poor design with the seal through to the little 25hp 4 stroke not having the robot at the factory connect the throttle cable up correctly forcing it to get stuck at 3000 odd rpm on the first outing. Every outboard can have issues, biggest thing that causes problems is the user and operator with a lack of maintenance and care.

Personally Mercs have had a bad run in our family, black anchors as such. Probably just struck a bad one for the 4 hours we got to use it as a loan motor.  Just thinking about the choices, Merc have developed their 90-115hp range considerably in the last 4 years from where they were. (weight wise and what not) Honda no real developments since we purchased in this hp bracket just whipped out the 100hp outboard, still the same block though.. Back to the point. Mercs have spent time developing and advancing their product, could be a bad thing, could be a great thing. Someone has to be the test pig 
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"steps" you are so easy to wind up,couldnt resist.
QMS is not WORKING
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If you believe anything I have said above is incorrect, that my maths is incorrect
 Then say so and why.
 I have posted my experiance of the last 50 odd yrs before.. 
Posted the why and hows, the sources, of the maths, the application to real life scenarios, and the limitations of my knowledge and hands on application.

 Rather than simply post up innuendos implying  of bush mechanic as a judgement, If my calculations and  real life hands on data basis are incorrect.. say so and the why.

 A truck drivers license doesnt make a good truck driver right..
 A deg in communication and politics doesnt make a good PM right..
 A trades cert doesnt make a good tradesman ...
 






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I didn’t realise you had to be a new part changer (qualified mechanic), to give an opinion....
If you only want to listen to 2 people, why not just pm them instead....
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"steps" are you a qualified outboard mechanic or just a bush mechanic who has done a lot of reading,I know there are 2 reputable members on this thread and I would take their advice.
QMS is not WORKING
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Boffin?  well been asked

I've never been a huge fan of the highest output model of a given block.
For example in the Hondas, the 80, 90, and 100 are all the 1.5L inline 4.
Aside from just revving it a bit more, it would be interesting to know what, beyond an ECU calibration, has been done to get 20 more hp from the 100 over the 80. I always wonder if it just makes for a more highly-strung, slightly less reliable motor.
 A engine of a given volume requires a mixture of a given volume..at a very close  AFR (air fuel ratio). and that proportion of the ratio which is fuel has a given amount of  potential energy stored in it.
 This amount of energry can be increase by raming ( turbo/ blower ) more fuel mixture under pressure  in effect increasing the volume of the engine... but this is not the case here.
By changing cam profiles.. how lomng the inlet is open. how long the inlet and exhaust are open at the same time oine can change the amount of fuel mixture in the chamber , and the compression pressure.. then ( see previous  bofin post on octane , cylinder pressure , time of flame across the cylinder timing and metering (carb or injection)
 These variable therefore change the amount of hp/ torque at any given rpms.
 In saying that , I do not understand the justification huge difference in price between hp models outside simple profit taking..

All of that said, I was recently out on a DNA 535 with the 80 on it, I was very impressed, extremely smooth and quiet, and the best bit was we did probably 40km that day and the fuel gauge barely moved off Full. I would be surprised if we used more than $50 of gas.

 You mentioned the gear ratio// rpm range...
Storta right.. In this case I believe all the hp models have the same gearbox ratio ( have not checked this..)
 The final gear ratio is the prop pitch.
A boat of a given gross weight on the water (wild off the cuff guestimate of 535 say 1100kg).. 
with say a yammy 80 hp motor  will have a WoT of around 37 mph @  approx 5500 rpms 2.31:1 pitch 17
 A cruise @ around 4000 rpms of 25 mph requires approx 40 hp
Put a 115 yamm on WoT will be approx 44 mph @ 45 mph and have a 19 pitch prop ( nicely powered for 1100 kg)  2.15:1
@ 4000 rpms will travel  at cruise @ 4000 rpms 30 mph requires approx 52 hp
 If travel at the same cruise as peed as the 80 hp (approx 2200 rpms) will use far less fuel... and will use far less fuel than the 80 hp. a good 10 to 15% less..
 But get well powered, hull performance increases dramatically and is far easier/ comfortable to travel at the higher cruise speeds including in chop..uses more fuel to move the same weight... But far less fuel than to travel at the same higher cruise with the smaller 80hp.

 So yes the 80 hp wil be economical with the smaller 80hp (if travel at a normal cruise for that sized engine)
 but not as economical if have a larger engine.

 Hope that boffin stuff explains your question..confirms your perception  with the science/ number crunching behind it. 

 Anyone got the WoT,  preferably fully loaded speed of the boat and hp on the back real like numbers? Dont need pitch etc.
Then can calculate the gross weight of the boat on the water.

Am going with 2 batteries and may put them in console (as is the norm overseas) - that moves 35-40kg of dead weight off the transom.
A boat that size even powered with a 80 will not make a difference.. a 115 even less.. and if the weight is more than 1100kg guesstimate, hull design has the bow up a little.. put a prop on with a little more rake ( 4 blades tend to generically have more rake..( its the rake not the blades that make the difference in bow height)

 
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Nelson region - I have very handy Merc & Honda dealers but Yamaha is 60-90 mins away in a real PITA location to take a boat. The Yamaha service is good once you're there but their regional service is not what it used to be since other shops closed down &/or dropped them.  I believe Yamaha NZ are aware of the issue.  You only appreciate the value of a dealer in close proximity when you need some urgent work during peak summer periods and they tell you to get in the queue behind the Merc and Honda customers !
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Post Options Post Options   Likes (0) Likes(0)   Quote RC1 Quote  Post ReplyReply Direct Link To This Post Posted: 01 Jun 2018 at 8:34am
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Joined: 22 Mar 2009
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Points: 1070
There must be a local Yamaha dealer in your area, where are you based ?
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Post Options Post Options   Likes (0) Likes(0)   Quote Gappy Quote  Post ReplyReply Direct Link To This Post Posted: 31 May 2018 at 8:02pm
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Papa where are you based?
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Post Options Post Options   Likes (0) Likes(0)   Quote Muzzfishing Quote  Post ReplyReply Direct Link To This Post Posted: 31 May 2018 at 5:03pm
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Location: Cambridge NZ
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Papa I think you will be very happy with the performance of the 115 Merc. Plenty of power and good economy.
    A Good Skipper Keeps the water on the outside of the boat.
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