Evinrude Lightwin problems

[ausob-collector]

Thanks very much for your advice, Johnyrude. I have replaced the plug leads, plugs, condensers and points so now they are free from suspicion but I am going to get an inline spark checker like you suggested tomorrow.
When the engine is running, I can lever off the bottom plug wire with a pair of pliers and it will still run the same, on the top cylinder but I can feel the jolt of the spark from the boot when it is off the spark plug, so a lack of fuel to the bottom cylinder is most likely the problem.

I just thought of the reed valves being the problem, with maybe one opening more than the other or a bad gasket?

Could a non-sufficient earth for the electrics also be a problem?

Thanks again for all your help and advice
BP

[crosbyman]

btw… any compresssion numbers ? did I miss those ?

insufficent earth … ground… unlikely since one plug is working

Joining AOMCI has priviledges 🙂

[ausob-collector]

95psi top cylinder
90psi bottom cylinder
I have taken the reed block apart an discovered that the gaskets between it and the block are broken, causing an air leak and one of te reeds was only opening very slightly, which was for the bottom cylinder.
I have cleaned and replaced gaskets an now it is back on the motor, and I can now hear the squeaking of the reeds opening as closing as I turn the flywheel.
There is not much else that could be wrong with it so I will give it a run today and let you know what happens.

Thanks again
BP

[cajuncook1]

AusOB_Collector,

Those are really good compression numbers for a lightwin. Did you get those numbers with using the manual starter or did you use a power drill to turn the power head???

Good find:

quote :

I have taken the reed block apart an discovered that the gaskets between it and the block are broken, causing an air leak and one of the reeds was only opening very slightly, which was for the bottom cylinder.

[ausob-collector]

CajunCook1, those compression numbers were after the first unsuccessful try run, with the recoil starter. Dry compression test came in at exactly 90psi on both cylinders, so that isn’t an issue. New base gasket has been installed so exhaust and oil isn’t spraying out from between the powerhead and leg. I am waiting a bit so the thread locker I put on the reed valve screws can cure so they still don’t vibrate loose, is there a specific setting for the reeds (as in how far they open or something along those lines) I nee to know about? Because right now they are back together the same way I took them apart(except a lot cleaner) 😎

Anything else important I should know or check before the test run tomorrow?
(FYI as I am in Australia that is why I say tomorrow as its 9.20 at night right now!)

Thanks again for all the help

Cheers
BP

[cajuncook1]

[johnyrude200]

If you had a leaking leaf valve plate gasket(s), that could easily cause a lean running condition. If you have the whole motor apart you can always put a drill on the flywheel nut with a socket and turn the motor over using the drill gun. Turn it over CLOCKWISE, continuously, and you can watch the ignition system working real time, and if the carb is off, you can watch to see if the leaf valves are fluttering (it will be very obviously).

If you don’t see them fluttering fairly evenly, that provides more detective work/clue toward the root of the issue. Once you’ve ruled out ignition and manifold, that only leaves 1 more thing, assuming the exhaust side it OK.

Those 3hp motor are very simple, except it takes a few extra steps to strap the fuel system back on in between repairs when you’re going through test trials. Good compression numbers, too!

[ausob-collector]

Hmmm, CajunCook1 I can’t open the file you attached as I don’t have the required permissions to open it.
Would you be able to send to my email?

Thanks again
BP

[cajuncook1]

AusOB_Collector, I sent these to your email address. I removed your email address from your post so spamers could not send junk to it. I can replace if you want. The diagram I originally posted for you is located in the service manual on page 35.

1965 Evinrude 3hp Service Manual
1965 Evinrude 3hp Parts manual
1966 Evinrude 3hp Owners manual

Cheers buddy,

cajuncook1

[ausob-collector]

Thanks very much CajunCook1 for that. Should come in very handy at some point.

Cheers
BP

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