Lightwin 3hp / firing on 1 cyl

lbdavis

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Jul 22, 2010
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Hello again,

3302s 3hp 1963 Evinrude.

So I got my spark, put it in the tank, fired her up, adjusted the low speed needle and got it running like a top. then I put the cowling, etc on and now it only runs on one cylinder.

I re-checked spark and it was still there.

Quick background: When I first revived this motor last year, it also ran on one cylinder after breifly running on two. Occassionally, the 2nd cylindar would fire, but mostly just 1.

I'm thinking that I have a compression issue or I need to adjust a point. I fear the former. :eek:

Any ideas?

As always, thanks a bundle! :D
 

lbdavis

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Jul 22, 2010
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Re: Lightwin 3hp / firing on 1 cyl

Also worthy of note:

I've just rebuilt the carb, replaced the head gasket, replaced all parts on the stator plate, installed new impeller, new plugs... I think that's it.
 

1946Zephyr

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Oct 21, 2008
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Re: Lightwin 3hp / firing on 1 cyl

Oops....sounds like an ignition issue. Did you replace the spark plug leads when you worked on the ignition system? If you don't replace the spark plug wires, then it is best to trim off about 3/8" off the end and reconnect it to the coil with fresh new contact. Also check the connections in the spark plug boots. Trim off 1/4" there and re-attach the boot assemblies.:cool:
 

lbdavis

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Re: Lightwin 3hp / firing on 1 cyl

I did replace the spark plug leads w/new copper stranded leads. I seem to have a really strong blue spark that easily arcs 1/4"+. I feel like I have the points set pretty well at .020, but maybe not. If one of those were off, could that cause the problem?

Could poor compression be to blame? It did run on two cylinders beautifully for about 5-10 minutes... (I know I should check, but the cheapest tester in town is $60 and I'm trying to do this on the cheap)
 

bktheking

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Re: Lightwin 3hp / firing on 1 cyl

Point gap is all about timing, and if it isn't set properly the plug will fire at the wrong time causing it to fire on one cylinder. Could also be a compression issue, you need to test it.
 

lbdavis

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Jul 22, 2010
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Re: Lightwin 3hp / firing on 1 cyl

~67psi on both cylinders. I only ran the engine on the one cylinder for about a minute before the test. Is that enough compression for this motor?

Another thought I had, and this is probably silly, is that when she was running on two cylinders, I didn't have the silencer and screen on the carb. Could the reduced air intake be causing this?
 

bktheking

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Re: Lightwin 3hp / firing on 1 cyl

Should still run and the compression should be fine.
 

lbdavis

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Re: Lightwin 3hp / firing on 1 cyl

Ugh. So I just took things apart, and set points to .020, again, and re-assembled. (I'm getting fast at that). Put the engine back in the tank. Still one cylinder firing.

To be sure I'm doing this right: I'm setting them to .020 when the tiny little arrow next to "top" on the cam is directly on the "brush". Is that correct?

If points are right, I've got spark, I've got compression, It seems to be getting fuel.... What am I missing?
 

bktheking

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Re: Lightwin 3hp / firing on 1 cyl

Reeds, crank seal, some other gasket.
 

cajuncook1

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Sep 3, 2009
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Re: Lightwin 3hp / firing on 1 cyl

Have you isolated which cylinder is dropping? You've stated that it runs well for about 5 or 10min and then it seems to be running on one cylinder.

**Make sure your vent plug is open on your tank when your running/starting your motor. (You may laugh, but all of us have forgotten to open that vent plug while starting up the motor in the morning for a day of fishing and find a little while later the motor is running like do do, because the air can't entering the tank and allow adequate flow of fuel out of the tank. If the vent on the cap is open then make sure it is not clogged with dirt or grease.***

If one of your coils is going out (after the motor is warmed up), then you want to isolate which cylinder is the the culprit. Start up the motor(in the water) and let her warm up and when you notice it running rough or "on one cylinder" then start the process of isolating which cylinder is the culprit.

Carefully (don't want to get a little jolt :D ) unplug the boot to the top plug, if runs rough but maintains some then the bottom plug/cylinder is firing. If it dies then you know that the bottom cylinder is not firing/spark. Replace the top spark plug boot carefully and let a run for a minute or two, then unplug the bottom plug boot, if it dies then you know that you have the top cylinder plug/wire that is not firing/spark. If runs rough but maintains some then the top cylinder is firing.

If you are able to isolate which cylinder is not firing, then switch coils. If the same thing starts happening on the opposite cylinder then you need a new coil. If the problem is continuing on the same cylinder then you need to replace the points, condenser or check if there is a short.

Borrowed this picture from JB Jennings. ***Make sure the points adjustment screw is tightened while setting the point. If it is loose or stripped then that will need to be corrected, because the points gap will change to a wider gap or close...then no spark.**

Pictureofpointcondensorandcoils.jpg



Just a thought
 

lbdavis

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Jul 22, 2010
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Re: Lightwin 3hp / firing on 1 cyl

Looks like it's time for me to buy some service and parts manuals.

There's a plate on the back/side of the power head that appears to not be sealed well. I'm guessing that's the crank seal that you speak of, BK? You think an air leak here could cause a problem? I don't even know what a reed is... So much to learn.

Does anyone have a suggestion for the best place to get manuals? I've seen many places that sell them. Are factory ones the best or are generics better?

Also, I see that Napa seems to carry most of these parts as well. I'd love to get a parts manual that references Napa parts as well as Evinrude parts. I'm a cheap bastard. ;)
 

lbdavis

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Jul 22, 2010
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Re: Lightwin 3hp / firing on 1 cyl

This is the "leaking" I am referring to:
36lhasl

Hopefully that pic posts...
 

Chinewalker

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8,902
Re: Lightwin 3hp / firing on 1 cyl

You mentioned earlier on that it dropped the cylinder when you put the cowling on. Are the wires and plug boots on good shape? It's a tight fit with the cowling on and I've had a couple over the years where the old wires would arc through to the cowling or gas tank.

Your compression readings look about normal for those old 3s. If you had a blown head gasket it would show up as lower compression on one cylinder.
 

lbdavis

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Re: Lightwin 3hp / firing on 1 cyl

Hmm. Interesting. Things are tight in there.

There are new wires(leads) in there, so I wouldn't think there would be arcing, but I suppose that could happen. FWIW, it still runs on 1 cyl now that the cowling is off...
 

Happy_Jack

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Aug 13, 2009
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Re: Lightwin 3hp / firing on 1 cyl

Chinewalker made a good suggestion that the cowling may be causing the ignition to ground out, you say it does it even with the cowls off, but yet, it is still dropping a cylinder (losing spark to one) others have given spot-on ideas on how to isolate that, I would just add that you said you have set the points several times, but have you CLEANED the points any of those times?
Even if already clean, and you use an oily feeler gauge, it can foul the points surfaces, causing them to arc to ground, and not produce good spark.

That was one of the things I recommended earlier, set and CLEAN the points.
I have had times where I have actually had to clean an old set of points a few times before they stopped causing issues. The tungsten ignition points faces get oxidized, and can be difficult to get them properly cleaned & dressed to eliminate issues.

I would try to clean the points again, using 320 and 400 grit sandpaper, then wipe them clean with laquer thinner on a soaked strip of business card drawn through the closed points, use a new piece of cardboard dipped in LT each time until it comes out clean. When it draws through clean, open up a set of points and look at it.
Is it clean, shiny and uniform? if so, it is clean.
Is it dull, mottled and show different discolorations? if so, it is drirty, do it again.
(Some say sandpaper is not good, or use a higher grit...that's fine, use what you think is best, but do clean the points, and the 320/400 grit has always worked just fine for me)

If it is not that, I would tend back towards the coils having a short to ground underneath, where they contact the stator plate. Impossible to see unless the coil is removed, a tell tale black strak/mark should be present if this is the case on both the coil, and the metal stator plate base.
 

Happy_Jack

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Aug 13, 2009
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Re: Lightwin 3hp / firing on 1 cyl

Your picture shows an image of the exhaust cover.
If the gasket on that is bad, it will usually cause:

-a small exhaust noise if leaking to the outside.
-interruption of cooling water if leaking to the inside.

Be careful when removing those screws if you decide to go in there, they are quite small, and are easily snapped off, leaving you with a difficult removal job.

Likely that has nothing to do with your issue, the crank seals are on the top and bottom ends of the crankshaft where it exits the crankcase (block)
 

lbdavis

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Jul 22, 2010
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Re: Lightwin 3hp / firing on 1 cyl

Thanks, Happy Jack.

I'll follow your's and other's suggestions this evening.

One more quick question before I do: Since I still see a strong spark at both plugs, is it possible that dirty points are the problem?

::handing each of you virtual 6-packs::
 

Happy_Jack

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Aug 13, 2009
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Re: Lightwin 3hp / firing on 1 cyl

Well, at this point, we have pretty much covered all of the possibilities, lots of great suggestions from some knowlegable guys, but it is always worth double and triple checking the small stuff.

You have bright blue spark...BUT you keep losing it on one of the cylinders, that makes this an intermittent issue, tough to nail down.

I suggested the points cleaning, because often, a quick wipedown is not enough, and if those are not properly breaking the circuit, intermittent spark COULD result.

Remember, as I said, it COULD be any number (or combination) of the things outlined by myself or the other guys....got to keep hammering the basics until you find it.

good luck.
 

lbdavis

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Jul 22, 2010
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Re: Lightwin 3hp / firing on 1 cyl

I believe that I might not have ignition troubles, here's why. (then again, I'm a n00b) :D

I followed Cajuncook's suggestions for isolating and troubleshooting and here's what I found after using technique ~6 times:

- w/ engine running rough (note I didn't say on 1 cyl) I disconnected top boot
- Engine now runs even rougher and *really* seems to be running on 1 cyl
- After plugging top boot back in (it still had spark), I disconnected bottom boot
- Engine dies slowly (one time it ran for a while)

So I follow Cajuncook's suggestion and Happy Jack's suggestion and I swap out coils, clean and reset points (w/400grit and thinner). I cut leads shorter to get a fresh connection on coil/lead and reinstall everything.

- Engine runs well for ~2 minutes. I kill it, install silencer, restart, and it goes back to "running rough" w/in 30 seconds.
- unplugging plugs one at a time, I get the same exact results I got before swapping coils.

The problem is in the top cylinder. It seems to me that the top cylinder is firing but getting poor combustion. Since fuel and air are the only other two factors for combustion, is it possible that the lower cylinder is getting proper fuel/air and the top cylinder is not receiving proper fuel/air?
 
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