Evinrude Lightwin problems

[fleetwin]

The correct fuel/oil mix for this engine is 16:1, no matter what any book or oil experts say. These little engines have plain bushings on the rods that need all the lubrication they can get. A well tuned Lightwin/JW will not smoke much at 16:1 either.

[ausob-collector]

When I said that I checked the electrics, I tested the coils (good primary windings etc. and not cracked)and they are fine, cleaned and reset the points to .020 and replaced the ignition wires.
The ignition is fine.

Thank you for your help so far.

Cheers
BP

[ausob-collector]

Well, another possibility eliminated.
There is only minimal carbon deposits in the exhaust chamber, and the ports were clean.
See photo attached.
I also just regapped the plugs at .030 and reset and cleaned the points just in case.
I’ll give it another run soon.

Cheers
BP

[johnyrude200]

Maybe I’m stating the obvious, but haven’t heard anyone mention, did you check to see the high speed jet is clean and make sure that needle is set correctly? That one on a JW usually is between 1/3-2/3rds turn out. If you’re fuel system was dirty, chances are some of that got trapped in the high speed jet, which supplies the lionshare of fuel to the motor.

Make sure your float is set right too…level with the upper carb casting when upside down. Make sure you’re testing it with the air silencer and mesh screen on it. Some of these motors just won’t run right without those two things in place (ran into one of these about a month ago…whereas previously they all ran fine without the screen or silencer in place).

Agree with FrankR…that spark should be AT MINIMUM 1/4 inch bright blue spark on an air-gap tester. It’ll run with 1/16 – 1/8th spark, but 1/4- 1/2 inch is the right way it should be.

[The Boat House]

• This reply was modified 5 years, 5 months ago by The Boat House.
• This reply was modified 3 years, 2 months ago by The Boat House.

[ausob-collector]

Tubs, yes I have checked that and it is completely clean and free of any carbon build up.
I have just replaced both coils to completely eliminate any suspicion about the ignition, will try and start it ASAP to see if it’s fixed.

Thanks again

Cheers
BP

[ausob-collector]

Well, now that she is running, it is obvious that she is only running on one cylinder. When I turned the fuel off the cylinder picked up and it ran on both for a short time before it stopped.

Would the insulation on the points assembly or the condenser have anything to do with this?

Thanks for all the help so far

Cheers
BP

[billw]

Usually that means the carb is set too rich, like Johnnyrude said. However, it can also mean a fouled plug. I would throw in another set and retry. A cheap and easy experiment. I have been fooled by a sub-par plug, that I thought was okay, before. You might also try backing each plug boot off the plug, while the engine is running, using insulated pliers. (Purpose-built, plastic pliers are best.) Sometimes, a fouled plug will pick up and start firing, if the ignition is made to produce its full voltage potential this way.

Long live American manufacturing!

[johnyrude200]

If there’s any advice I can give you, is to remember you may have multiple problems going on at once with this motor. Go 1 system at a time to eliminate issues systematically.

Make sure mechanically the motor is OK (gearcase/powerhead/etc).
Make sure your timing is set right between fuel/ignition.
Fix your ignition system first.
Fix your fuel system next.
Run the motor, now check the cooling system or other issues (i.e. exhaust flow plug, etc).

If it isn’t running right, or new problems are revealed, go them one at a time (i.e. calibrate carb, listen for rod-knock, etc).

Otherwise you’re going to start to hate working on these things!

[johnyrude200]

quote BillW:

However, it can also mean a fouled plug. I would throw in another set and retry. A cheap and easy experiment. I have been fooled by a sub-par plug, that I thought was okay, before. You might also try backing each plug boot off the plug, while the engine is running, using insulated pliers. (Purpose-built, plastic pliers are best.) Sometimes, a fouled plug will pick up and start firing, if the ignition is made to produce its full voltage potential this way.

If you haven’t checked the strength of your spark, this could mean you have low voltage coming from that lead. Before swapping plugs, swap plugs on the cylinders. If the same cylinder is presenting the same issue, then you ruled out plugs and saved yourself a few bucks. If the problem migrates with the plug swap, then you confirmed it is the plug. Go get an air gap spark tester from your local automotive store, in fact, buy two. 1 for each lead. They cost about $8 each and are a must-have for problem diagnosis with ignition systems. Without the proper testing equipment (I.E. merctronic), it’s going to be a trial-and-error approach evaluating your coils, condensors, and points.

Old plug wires can cause a huge amount of problems too. If your wires are dry, taking permanent form, then get new ones. Although you may not SEE any holes, chances are there is a ton of electricity leaking out of those wires if they are originals or just old/dried out. Pull your plug boots off and see if the end of the leads are corroded, this is common. If so, snip off an inch, and if salvageable, re-install the boot and terminal. Check your coil to wire connections too.

Remember plug wires are like water pipes. They leak electricity just like a leaky water pipe. Problem is you almost never see the electricity leaking out. If you have weak spark, you have to go backward through the system step by step to race the root of the problem.

If you have low spark on that cylinder, it’ll run right at the low end but then miss at higher RPM due to higher compression in the cylinder. That means you have something wrong with that half of your magneto system. It’s possible you have a timing issue too, but that’s a long shot.

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