Help Please on Lightwin Carb issue?

[fleetwin]

OK, thanks for the info. I understand now, the engine idles down but only at a higher than normal throttle setting. So, ignore my yammering about "the powerhead must be in good shape" if the engine idles down nicely. Sounds like you have checked fuel flow pretty thoroughly also, but go ahead and remove the fuel line letting fuel flow into a glass jar for a minute or so.
At this point, it is hard for me to recommend anything in particular. You might try using this engine’s carb on a good running lightwin to rule in/out carb problems. I’ll reverse my advice again and ask about the intake gaskets, does it look like the intake manifold has been off/disturbed? Does it look like the crankcase has been split/apart before? I’m assuming you have had the head/exhaust cover off cleaning out all the salt. There is a slight compression difference, about 6%, did you see any excessive scuffs/scores/stuck rings?
The symptoms you describe don’t seem ignition related, but I am not there and can’t hear seen the engine running. At this point, I am leaning towards internal powerhead problems/excessive wear, but don’t want to condemn the engine based just on what I’m reading.
Thankyou for providing answers to my continuously changing questions, any chance of doing a running video?

[seakaye12]

Well; here’s a video. I’m not sure if it asks more questions than it answers…..but it is what it is.

Note the way the motor sounds "loaded up" when it first starts….but clears when accelerated and then slowed down. Also note that it rarely; if ever starts easily on the first pull; even when warm. Lightwins aren’t typically like that. Also note that whil it idles down quite nicely…it does so with the throttle lever about halfway between START and SLOW…..not over by SLOW like the typical Lightwin.

https://youtu.be/g55NJhJv_fs

[cajuncook1]

It looks like there is a mid 1956-58 JW tank, starter, and ignition plate and throttle on a mid 1960’s Evinrude lightwin powerhead, exhaust housing, and lower unit.

Is the carburetor from the lightwin or JW?

I am not certain if the lightwin’s carburetor’s cam follower and the JW throttle cam exactly match up for the proper synch between the carburetor and the ignition. (I am not certain of this, so maybe someone with experience in this matter can comment.)

Interesting

[seakaye12]

You are correct. Everything is 1964 E’rude except for the tank, starter, tank mount and throttle lever. (And the Cowling itself which isn’t on in the video). All that is a 1956 JW-12R Johnson.

The carburetor is the original 1964 E’rude carb…but with the lower half (bowl) swapped so as to provide an adjustable HS needle.

[david-bartlett]

This is a very interesting thread. I don’t see a lot of differences in parts between the various years on these motors, to that should not be the issue. Going to likely be something simple once you find it. Can’t wait!

[fleetwin]

OK, well it seems to run pretty well, didn’t seem to be hard to start…
The only thing I noticed was that it didn’t seem to slow down too much when you revved it to WOT then cut back to start position quickly. Did anyone else notice this, or is it just my imagination. Are you sure the carb linkage is free/not binding. How about the throttle cam, these get bent back easily if the throttle plate had been stuck at some time earlier. I know you mentioned that the cam pick up is correct, so I guess the throttle cam isn’t an issue, but it just seems to be running kinda fast in the start position.
Let’s see what others think….

[seakaye12]

fleetwin…

yeah; that’s why I wanted to use a TinyTach. It’s hard to hear in the video…..but listen starting about 45 seconds on thru 1 minute…you can hear the speed varying up and down. Sometimes the range is more than that; it wouldn’t cooperate for the video….

BTW….your prompting me to check fuel flow actually resulted in my finding a plugged gas cap vent on one of my Lightwins! Thanks!

[seakaye12]

Here’s another video. I put this one up on VIDME…lots easier that wrestling with Youtube….

https://vid.me/aixy

[fleetwin]

OK, heard it that time on start up. I’m guessing one cylinder is kinda lean due to an internal problem and it takes it little running to get the weak cylinder totally online….That video was with the replacement carb too, correct? Again, you could try the suspect carb on a good running engine to rule out carb problems. The only simple internal problem I can think of is if the intake gaskets are reversed or perhaps one of the reeds isn’t closing up very well, does it look like the intake has been off before? Be careful if you decide to remove the intake, those gaskets can be hard to find. The only thing that might be worth trying is to retard throttle pick up some which will allow the throttle plate to be closed at a more advanced ignition position which will let the engine run a little richer.
Unfortunately, my two cents is on an internal problem/crankcase leak/poor primary compression causing the loping and lack of idle.
What did the pistons/cylinders/rings look like when you had the head/exhaust cover off?

[seakaye12]

OK; the first two videos were with the original carburetor. The one that came with the engine in 1964; modified only by putting the older bowl assembly on.

The video linked below is the engine with a different carburetor; from another 1964 Lightwin. It has the fixed HS jet #28.

I think it runs better; there is less variation in RPM. But; it is still not perfect. I guess this is the best this little motor can run. It actually runs fairly well; just not like it really should. But; it’s had a hard life. I imagine it has a bunch of hours on it; the cylinders pistons and rings looked ok; but I have no doubt that it all has a lot of wear.

I have only a basic understanding of "primary compression". I have been assuming that with the compression I measure with my gauge…the engine should run well.

As for the idle; it idles pretty well; I think. There again; maybe not perfect…

fleetwin; you’ve asked a few time now about the reed assembly. Sorry for ignoring that inquiry. Yes; it has been disturbed; early on I swapped the two pieces from another parts motor. I replaced the gasket at the crankcase; the two halves were not disturbed. The swap yielded absolutely no change…so I doubt there is an issue there.

The engine with a swapped carb:

https://vid.me/e/hH42

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