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50Hp Merc 50ELPTO tuning issues

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Post Options Post Options   Likes (0) Likes(0)   Quote u13turbo Quote  Post ReplyReply Direct Link To This Post Topic: 50Hp Merc 50ELPTO tuning issues
    Posted: 21 Apr 2017 at 3:16pm
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Hi guys. Im having issues with a tuning fault on my 1997 2stroke outboard. it intermittantly missfires causing poor running, but then will run without missing a beat.

Ive tested spark, replaced plugs, removed and cleaned up carbs. now I want to check timing and fuel mixture. being new to outboards im abit lost as to how to check/adjust the timing. I did find a nut loose allowing an adjustment screw able to rattle loose on a linkage(which I have a feeling is timing)

Can anyone shed some light on the topics above? Or where to get a manual for one of these engines aslong as it will help?

Thanks
Jared
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Post Options Post Options   Likes (0) Likes(0)   Quote notalloyit Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr 2017 at 3:50pm
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sounds like moisture in your spark coil packs, possible small crack.
suggest getting them tested.
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Post Options Post Options   Likes (0) Likes(0)   Quote u13turbo Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr 2017 at 4:55pm
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tested coils with a coil tester but as they require extra voltage from CDI it did not work. Put back into outboard and tested with spark tester while cranking, Had a very strong spark with a good 5mm gap
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Post Options Post Options   Likes (0) Likes(0)   Quote CanadianJohn Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr 2017 at 6:49pm
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u13turbo is this when running on muffs or out on the water? and only at idle?
 
they are not the smoothest running motor at idle. I had one from new and it would have a bit of a sneeze and stall. but started right up and was fine.
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Post Options Post Options   Likes (0) Likes(0)   Quote u13turbo Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr 2017 at 6:58pm
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This is out on the water. I go to motonau and its pain as getting out over the bar it bogs down, missfiring. after abit of throttle adjustment it comes back up onto 3cyls, but occasionally drops a cylinder.

Ive checked compression and it was all even(90psi iirc) checked coils, replaced plugs as they were abit worn but also fouling abit. Thats why I am wanting info on the correct specs for adjusting idle/air screw aswel as timing.

thanks for your reply
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Post Options Post Options   Likes (0) Likes(0)   Quote Kandrew Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr 2017 at 9:20pm
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Sounds like fuel to me, can't see it being timing or it would kick back on the starter. If it's electrical it will most likely be there all the time. Check for tiny pin holes in your fuel lines and make sure the fuel breather working ok
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Post Options Post Options   Likes (1) Likes(1)   Quote Kandrew Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr 2017 at 9:23pm
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And check the fuel pump diapham for a small hole. Weak part on the mercs and they can nip up a piston if the diaphragm isn't right.

Check for water in the fuel

Also When it starts to miss get someone to give the primer blub a pump, that will tell you if it's fuel.
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Post Options Post Options   Likes (0) Likes(0)   Quote u13turbo Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2017 at 8:10am
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      Thanks I will check the fuel pump diaphragm. But have a feeling it's not a fuel supply issue as I was at cruise (30kph) for a cintstamt 15minutes just the other day without an issue. More just when it's cold I guess.

I really need the standard seytkngs for timing and idle fuel screw so I can rule that out, and because it has self adjusted
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2017 at 9:57am
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Im with Kandrew.. fuel
 be it blockage, air leak, or picking up water.

I dont know mercs, but do know that more modern outboards.. yep even carbed 2S.. setting up timing correctly is nothing like our old cars....stuff needs to be disconnected run things set, run connected, re set, use a loading prop thingy ....
Timing is a workshop job, or if have a full repair/ service manual and understand the principles of timing and engines.
Anyone who knows about the principles of timing will tell you that within a band of 12 to 18 degs ATDC at a given load and mixture, cylinder pressure and fuel octane, there is a point that has a tolerance of max +/- 1deg, for optimum performance....
And if you move far outside that tolerance, espec on high performance type engines like outboards, get it wrong and your engine will die a slow to quick death.

I have spent near on 40 yrs messing with fuels octanes, timing, chamber pressures etc on carbed engines...vintage, classic , performance cars, data loggers etc....
I have a full repair/ service manual. I will check my timing... BUT WILL NOT attempt to re set if not right... This is an area I KNOW can be screwed up very easy with very bad results, and these 2S are very sensitive, requiring expertise and tools to go thu to re set...
 If you have played with timing... get to be reset by a workshop.

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Post Options Post Options   Likes (0) Likes(0)   Quote u13turbo Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2017 at 10:11am
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I hear what your saying, seems alot more in-depth than car timing. Problem is I have a hard time trusting that even at a shop it's going to be done correct if it's as difficult as you have mentioned.

As I said I have not messed with the timing but I found a linkage with the lock but backed right off allowing movement of the adjusting rod. Hard to say if it's moved or not but I need to find out exactly what that adjustment is for.
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2017 at 11:17am
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Problem is I have a hard time trusting that even at a shop it's going to be done correct if it's as difficult as you have mentioned.

 You been reading some of my old posts ?Wink
 
Yes that is why I do my own servicing and stuff now.. stuff that got missed doesnt anymore... but in saying that there is specialist stuff... and advise I get from our local workshop... well THE guy who knows his stuff..
 In saying that the long term staff in the workshop also know their stuff....
 Where things go wrong is when the new guy.. espec if younger, and coming up to workshop busy period, takes short cuts...
They get moved on.. often to other workshops...

 Have a chat to your local guys...and yeah need parts , oil screws, maybe a little more expensive cause they are the agents...but that support will be returned in like
 Ask and listen....ask why.. a little background knowledge will soon tell if they really know their stuff, or BS on stuff they dont...
Guy who know... they will tell, or suggest where to go to find out...those guys are the ones you want.... and support

 Edit:
These guys also know the quirks of an engine...called long term expriance...
eg Sons merc throttle got stiff.. he dismantled.. lubed checked everything bits everwhere put it back.. still stiff.
Brought the boat here, I looked, seemed to be in the leg (???)  rang the local guy.." straight away before I even finished, said " corrosion in the bush where ther gear box lever goes down into the leg... caused by water spray/ rain getting into uncovered engine or transducer type stuff .. merc are prone to it."
 To check out, we sprayed the bush with marine crc, worked it a little, and slowly freed up.
 
He now has a cover over the transducer like mine, and an engine cover to keep rain out... and dries the under engine cover after each day out...thu with the above it stays dry......oh and occasional mist sprays the engine with lanolin  now to water proof

 So not only did he tell us what was wrong , but why and what needed to be dont to prevent...
 Thats expert experiance..
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Post Options Post Options   Likes (0) Likes(0)   Quote u13turbo Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2017 at 11:59am
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Yeah absolutely agree with you it's finding someone you kbow/trust. I'm a car mechanic so it's all mostly cross over except specifics. I'm sure with a manual I can set timing, from what I've read I can set base timing without anything except a timing light. And due to it being this one adjusting rod that could have changed it should be easy enough?

Does anyone know who sells workshop manuals? Or online pdf versions?
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Post Options Post Options   Likes (0) Likes(0)   Quote jackel Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2017 at 12:10pm
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Sorry not meaning to totally hijack the thread...but

Corrosion in the bush where the gear box lever goes down into the leg... caused by water spray/ rain getting into uncovered engine or transducer type stuff .. merc are prone to it."

Thanks Steps-any chance you have a pic of the bush that you describe please? 
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Post Options Post Options   Likes (0) Likes(0)   Quote Durban Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2017 at 12:42pm
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What you can try as a trouble shooting method to find the fault is change the coils around between the cylinders if you don,t know which cylinder is miss firing .if its a faulty coil the problem will just go to that cylinder because the timing sensors has not changed [ there for the firing order remains the same ] this way you can determine if its a faulty timing sensor or the coil it self .doing it this method you need to determine witch plug is miss firing .it doesn't matter which coil you move to what ever plug the firing order will remain the same .

its sometimes not easy to determine which plug is misfiring what you can do is at idle on muffs pull one plug lead off at a time and listen for a drop in the idling[ when you hear a drop in the idling after pulling the lead off it means that plug is firing ] when you pull a lead off and the idling remains the same suspect that cylinder. i normally connect a timing light to the plug leads while its idling then pick up the rpm a little the timing light then points the faulty coil out .In your case you could have a faulty timing sensor or coil this you have to determine. there is a method i use to determine if its the timing sensor causing a miss fire .without using any instruments .
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Post Options Post Options   Likes (0) Likes(0)   Quote u13turbo Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2017 at 1:28pm
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I dont believe it is missfiring at idle, these motors just run quite lumpy i think. Its more under load, from a stand still until it gets abit of momentum up then it generally picks up on the other cylinder. And it can be intermittant. I really dont think its a coil issue as i have run them with spark tester jumping a good 5mm gap and they had a very strong looking spark.

As mentioned the adjusting rods locking nut was loose and has allowed the lever to self adjust, And i think it is the timing one. Wanting a manual to confirm aswel as get the settings required for me to attempt to time it up. Then i will retest on the water and go from there.

Thanks for all the replys so far.
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Post Options Post Options   Likes (0) Likes(0)   Quote Kandrew Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2017 at 1:32pm
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Just remember mate it's a 2 stroke no cams valves simple CDI ignition magnets in the flywheel go's past a pickup bang spark. Not a lot can go wrong either of three, pickup coil CDI. If you have a miss fire you will see it in the plugs.

Reason I say it's fuel because the fuel system on 2 strokes are a lot more complex because the fuel also lubricants the motor. Pump is not mechanical driven, diaphragm. Diaphram moves in and out with fuel crank pressure as engine cycles, if there is a problem engine will miss or not run properly at higher revs or underload

Where are you based?
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Post Options Post Options   Likes (0) Likes(0)   Quote u13turbo Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2017 at 3:55pm
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Yeah I just need to set timing as im 90% sure it is the adjustor rod that has been loose and self adjusting. So once that is definitely correct and the idle/fuel set on carbs I will look further into a fuel issue. But I cant until I set this timing up.

Based in Canterbury
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Post Options Post Options   Likes (0) Likes(0)   Quote pjc Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2017 at 4:29pm
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had a small 2 cylinder 2s years ago with simular problems,changed plugs leads etc ran fine till warmed up then would drop a cylinder then pick up after a cough and a splutter,turned out to be a resistor thing,when hot would break down.
going fishing tomorrow but tomorrow never seems to come.
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Post Options Post Options   Likes (0) Likes(0)   Quote Buzzliteyear Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2017 at 4:38pm
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u13turbo  What is your oil ratio ? Are you using a outboard oil ?
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Post Options Post Options   Likes (0) Likes(0)   Quote DIY Quote  Post ReplyReply Direct Link To This Post Posted: 22 Apr 2017 at 6:01pm
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Hi, if it's the Mercury branded Tohatsu then I have a workshop manual on PDF for the M40d2 and M50d2. Same engine with a few differences. Mine is the Mercury Lightning.
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