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1982 Evinrude 15 hp

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DrCoxie

Contributing Member
Hello,
if anyone remembers me; welcome back to me 15 hp evinrude. I've completed a few stints with my rebuilt engine and it runs good save for one issue, it likes to stall. So when i start it I turn the gas all the way up (as far as it will go in neutral), open the choke and pull once or twice which starts the engine just fine, push the choke back in and it'll idle but even when I leave the throttle at its maximum position it starts to reduce rpm and eventually stutters to a halt. It starts very easy after that, first pull but it always needs that max throttle position and eventually I'll get it to keep idling but then when I put it in gear and attempt to go full throttle it stalls again. Worth mentioning it wont really idle forever, it'll die eventually. Once all these is done the engine runs like a champ, seems to have plenty of power and when the boat is up on plane and the engines gets to chug away it does so, for how ever long I want it to. Anybody have any idea what's up with that?

Here are the details about the engine;
Fuel system completely rebuilt, new hoses, rebuilt fuel pump, carb cleaned three times, last time with ultrasonic, carb adjustments have been made to spec.
The compression on the engine at room temp without an exhaust on it in the dry was about 110 psi on both cylinders.
The electrical system has been checked, everything checks out, including coils. It has new plugs and sparkplug wires.
The reedvalves have been inspected and adjusted, looked really good and the whole engine has new crank case seals (all seals have been replaced with new ones)
Pistons were slightly scored (assuming it had overheated at some point in its life) but the rings were undamaged and didn't seem stuck, the cylinder walls looked fantastic (low hour engine)
The fuel tank has the vent screw open, the bulb hardens nicely when squeezed and softens a bit when the engine has run for a while.
 
I had this issue with my 1993 15 evinrude that I use for duck hunting. I was able to clear the issue with a new fuel pump and fresh tank of gas. Mine had the exact same issues.
 
Ben_jammin said:
I had this issue with my 1993 15 evinrude that I use for duck hunting. I was able to clear the issue with a new fuel pump and fresh tank of gas. Mine had the exact same issues.
Click to expand...

Mine already has a rebuilt fuel pump and it's a new tank of gas too, I guess the same symptoms can have different causes=S
 
(Quote Edited For My Understanding)

DrCoxie said:
.... 1982 15 hp Evinrude.....

1 -It likes to stall..... When i start it, I turn the throttle as far as it will go in neutral, open the choke, pull once or twice, the engine starts.....

2 - Push the choke back in and it'll idle, but even when I leave the throttle at its maximum position the rpms drop and it eventually dies out.....

3 - It restarts easily on the first pull but only with maximum throttle position.....

4 - Eventually it will stay idling but when I put it in gear and apply full throttle, it stalls again..... It wont really idle forever, it dies eventually.....

5 - Once all this is done the engine runs normally, seems to have its stated hp, and when the boat is up on plane, the engine runs as long I want it to. Anybody have any idea what's up with that?
Click to expand...

The compression is stated as being 110 psi on both cylinders. Remarkable! However, I see no mention of the spark being tested which should (w/all s/plugs removed) jump a 7/16" air gap with a strong blue lightning like flame... a real SNAP! Does it?

1 - That's a normal starting procedure... BUT... the terminology used about the choke is incorrect. To "Open" the choke butterfly is to push the choke lever in to turn the choke "off", having the butterfly in a horizontal position. Not to be nit-picking but rather to avoid confusion... the choke is either "Closed" (lever out, butterfly shut) or "Open" (lever in, butterfly open).

2 - That explanation indicates that either fuel is not being supplied to the carburetor... OR... the carburetor is somehow flawed.

3 - Indicates the compression and ignition is normal, but the fuel flow has been interrupted then re-engaged.

4 - A engine that idles okay but bogs out when throttle is applied normally has one or more of the following problems: (a)Throttle butterfly opening too soon in relation to the timing... (b)timer base sticking, retarded spark... (c)Internal carburetor fouling... (d)Fuel improperly supplied.

5 - Pertaining to your final question, and taking into consideration your explanations as per (Quoted 1 thru 5 above)... how your engine could possibly undo all of those encounters to run normally is a total mystery to me. I don't have a clue.

If a engine came into my shop with those flawed characteristics... that would spell out to me a failed fuel pump or a fouled carburetor... or both, of which neither would correct themselves.
 
Last edited:
joereeves said:
(Quote Edited For My Understanding)



The compression is stated as being 110 psi on both cylinders. Remarkable! However, I see no mention of the spark being tested which should (w/all s/plugs removed) jump a 7/16" air gap with a strong blue lightning like flame... a real SNAP! Does it?

1 - That's a normal starting procedure... BUT... the terminology used about the choke is incorrect. To "Open" the choke butterfly is to push the choke lever in to turn the choke "off", having the butterfly in a horizontal position. Not to be nit-picking but rather to avoid confusion... the choke is either "Closed" (lever out, butterfly shut) or "Open" (lever in, butterfly open).

2 - That explanation indicates that either fuel is not being supplied to the carburetor... OR... the carburetor is somehow flawed.

3 - Indicates the compression and ignition is normal, but the fuel flow has been interrupted then re-engaged.

4 - A engine that idles okay but bogs out when throttle is applied normally has one or more of the following problems: (a)Throttle butterfly opening too soon in relation to the timing... (b)timer base sticking, retarded spark... (c)Internal carburetor fouling... (d)Fuel improperly supplied.

5 - Pertaining to your final question, and taking into consideration your explanations as per (Quoted 1 thru 5 above)... how your engine could possibly undo all of those encounters to run normally is a total mystery to me. I don't have a clue.

If a engine came into my shop with those flawed characteristics... that would spell out to me a failed fuel pump or a fouled carburetor... or both, of which neither would correct themselves.
Click to expand...

You're right about the choke, I meant that I closed it (pulled the choke out)

I have a spare carb so I guess I will try that one out, so I can rule the carb out.

About the timer base sticking I'm not sure what that means, but I'll try adjusting the cam roller arm, see if that makes any difference.

Id be surprised if it's the fuel pump, since it runs so well when it does get going, since the carb only has a low speed adjustment it must have something to do with that, a fuel issue would mean it has issues running at full speed. Pretty much any issue with the engine should be noticable at full speed, save the low speed settings, so that should rule out a fuel delivery issue, up until the carb.
I am wondering about the spark, but since it starts so well and again, runs just fine on full speed that seems unlikely too, it's way too specific isn't it, an electrical issue that only turns up at idle speeds, unlikely isn't it? I haven't been able to rigg up this spark gap jump test but I found a guide to building one of those things so I guess if all else fails I'll have to check if I got me some bad coils=S

ps: ran hydrofoils on the engine the other day, planes more fully now but **** me sideways the boat is unstable, time to get the water out of the keel xD
 
Did you ensure that the carb is synchronized with the timer plate. There should be a line or arrow on the throttle cam that pushes on the carburetor's roller. When the throttle cam JUST touches the carb's roller, that line or arrow should be in the center of the roller. If it is not, it would need to be adjusted. This ensures the spark timing is correct throughout ALL rpm ranges, including idle.
 
flyingscott said:
What does that roller look like? Is it in good conditon?
Click to expand...


optsyeagle said:
Did you ensure that the carb is synchronized with the timer plate. There should be a line or arrow on the throttle cam that pushes on the carburetor's roller. When the throttle cam JUST touches the carb's roller, that line or arrow should be in the center of the roller. If it is not, it would need to be adjusted. This ensures the spark timing is correct throughout ALL rpm ranges, including idle.
Click to expand...

SOLVED! Thank you both and everyone else who responded, I tried a few things out, pumping the primer bulb didn't yield any improvement and neither did pulling the choke a bit when it was about to die and because the fuel system is completely rebuilt I set my sight on the carb so I started from zero with the carb adjustment but this time I set it to within 1/20 th turn where it ran the very best and followed the adjustment procedure very throughly and see there the engine runs like an absolute dream, I couldn't be happier, it stays idling for days and it responds to throttle at the drop of a hat and never stutters or bogs. Can't tell you how pleased I am about this long running project finally being completed, it was a complete rebuild of the engine (save the cylinders) and it was so worth it. Put some foils on the motor too and it ran an incredible 33 knots. I'll try to make a video of it tomorrow and make a new post so everyone on the forum who helped can have a look and enjoy it. Seeing a repaired engine run great is the best thing I'd imagine :D
THANK YOU again all!
 
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