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Best 150hp fourstroke outboard?

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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 12 Feb 2018 at 9:32am
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Titanium
Titanium


Joined: 14 Oct 2013
Location: Sth Auckland
Status: Offline
Points: 6367
At the end of the day there are a lot of 6m boats both alloy and fibreglass boats powered by 150hp four strokes and they seem to be happy with them so I'm sure it is adequate. Not fussed if cruising speed drops but yes I have been spoiled with hp to burn and it is nice to have plenty in supply when needed

 Yep.. as I posted a guestimate of 1700kg.. that I think maybe a little high(??) for THIS boat.. most 6m are quite heavier...
And from the calcs at 1700kg the puts the 150hp as  overall acceptable...subject to you thinking those numbers would be, assuming the 1700kg ball park correct.

Hoping to half the fuel usage for a days trolling front the 200 carby which I think is realistic based on what I have heard others are burning with there 150hp 4 strokes.

 Carbs by nature have a narrow efficient running rpm band width.. and it is NOT at low rpms....injection, then throw in modern technology, ECUs etc and you are now dealing in a whole new concept of efficiency right thru the band width.. be it 2S or 4S
 
What is important thu is having a prop suited for cruise out there  and  good grip at low rpms. trolling speed...I would be seriously thinking about a smaller 4 blade with good cupping and rake... in saying that will have to be very careful not to over prop at cruise/ WoT speeds... and this is where the smaller surface area (same dim) and smaller diameter of the 4 blade comes in to help that situation
Not just to take the benefits of the far better efficient rpm range but take full advantage it gives at the prop.

Cost is another deciding factor, the 150hp range as is at the upper end of what I'm able to spend so while a 175hp may be nice they are quite a bit dearer.

 Fully understand and relate to that..

the biggest block at 3.0L and supposed better torque down low as a result.
 
This basic internal combustion engine concept is true, but with modern injection and ECU control combined with modern cam design profiles, is now near obsolete , other than usefull marketing propaganda.
 Also the torque I think you will find is measured at the  fly wheel (the propaganda BS doesnt usually tell the full story)
 Where as HP is now at the prop.
You can create, and destroy torque by changing the final gear ratio of a car ( gearbox ratio and prop pitch)... and by changing the slip in a torque converter ( the diameter , cupping, rake number of blades , thru prop exhaust, and even how some props have several holes in the side of the prop..

Not fussed if cruising speed drops but yes I have been spoiled with hp to burn and it is nice to have plenty in supply when needed.
 That statement is very important.. to know/ understand that before hand.. and that cruising at lower speed will be the biggest economy factor.
 A while back .. Think was Tagit , posted about the effect on economy and even small changes in trolling speeds
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Post Options Post Options   Likes (0) Likes(0)   Quote Lethal Hooker Quote  Post ReplyReply Direct Link To This Post Posted: 13 Feb 2018 at 11:06pm
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Bronze
Bronze


Joined: 23 Nov 2015
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Points: 20
Hi Dunwurkn

I'm in a similar postion toying with the idea of replacing the thirsty Yamaha 150 SWS on my Tristram 581 with a new 150 / 175 four stroke. 

The boat drives great with the 150hp two stroke torque and acceleration but this time of year the range limiting and expensive trolling fuel consumption gets me motivated to look at upgrading. 

Be great if you could pass on any pricing info etc to help me decide what to do..

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Post Options Post Options   Likes (0) Likes(0)   Quote Dunwurkn Quote  Post ReplyReply Direct Link To This Post Posted: 14 Feb 2018 at 8:22pm
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Platinum
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Joined: 14 Sep 2010
Location: NZ
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Points: 2074
Steps I think the 1700kg would be pretty close, interesting comments on the 4 blade prop never new much about those, once I choose a outboard the fun then begins to find the right prop.


Used to have a 150sws and they are great motors but thirsty. Will pass on info for what I end up doing bit likely won't buy until the boat show.
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 15 Feb 2018 at 7:30am
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Titanium
Titanium


Joined: 14 Oct 2013
Location: Sth Auckland
Status: Offline
Points: 6367
once I choose a outboard the fun then begins to find the right prop.

 Once got good data of the set up with a know spec prop, even just out of ball park... selecting the right prop is usually damn  close if not spot on.
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