Evinrude 3 hp Lightwin 3012 diagnosis

[frankr]

The nylon plug is a fogging port

[Buccaneer]

Fogging port does not sound like something they
would have had in 1954 when mine was built.

Prepare to be boarded!

[Buccaneer]

If it weren’t Sunday I’d be swearing, lol.
Took that carb apart again this morning.
Decided that the High Speed Nozzle "had"
to come out, as that’s the only thing
I hadn’t checked, or re-checked three times!
Used the bottle torch and vice grips against
better judgement, as a screwdriver wan’t
going to do it. Finally got it moving,
but had to use heat and vice grips
most of the way! Found two of the six
cross holes in the nozzle plugged,
and some crud in the hole.
Cleaned said nozzle, made a thicker leather
nozzle boss gasket to insure a good seal.
Tried it out, and no improvement….
it still abruptly quits at half throttle,
no mater where I adjust the low speed jet.
To get the high speed "leaned out" at full
throttle, the high speed needle is only
1/4 open. Perhaps a red flag there?
I don’t see how fuel could be by-passing
my nozzle gasket…… looks like it’s
compressing nicely.
What’s really baffling is that I had it running
so nice for a while yesterday!
At rope’s end, so I took the 1956 Lightwin
off the rack. Never touched this one yet,
but the carb looks exactly the same, so
it’s apart and soaking in carb cleaner now.
Perhaps tomorrow I’ll determine if the
original carb is buggered up some how,
or other problems.
Regarding the silencer "fogging port".
The 54 did not have any such thing, but
the 56 does, albeit, it’s a little metal
"snap in" plug, not nylon.
I’m betting those plugs got used more for
"ether" injection than fogging oil! 😮

Prepare to be boarded!

[Buccaneer]

Update, Update- I went thru the carb from a 1956 Lightwin,
thorough cleaning, new nozzle and body gasket, and
installed it on the the problematic 1954 Lightwin.
Ran it without the silencer and cowls on, tuned it in,
and ran nice……..
https://youtu.be/5veZkXCZIgc

Put the silencer on and would no longer run right at
any speed…….. seemed like it was surging. Tried
re-adjusting the high and low speed needles,
but I couldn’t get it to run right.
I thought maybe with the silencer on, it was sucking
in exhaust by the back of the engine where it was
thicker. Held a fan up and blew fresh air on
the motor, and it made no difference.
Tried putting a three foot piece of 3/4" ID heater hose
over the end of the silencer to act as a snorkle
to "fresh air", but it would kill the engine!
Tried tuning some more but things just went down
hill…… kept dying, etc.
Took silencer back off, re-tuned the needles, and got
it running good again.
Decided to put a hold on this project until I get the correct J6 plugs,
as I’m running the J8’s now. Also noticed after the fact that
when I put the different carb on, that it’s no longer "synced"
to the mag plate correctly, so that will have to be re-set as well
before I try again.
The silencer is clean as a whistle inside.
Could there be a mechanical defect in the engine that
would cause it not to run okay with the silencer on?
Running out of ideas, lol.

Prepare to be boarded!

[Tubs]

Although not exactly the same I had a similar issue with
a Lightwin many years ago that might be worth checking.
Mine would run OK with the silencer off but poorly when
I put it back on. Found the exhaust passage was blocked
with carbon down to the size just a little bigger than a
pencil. Your motor doesn’t sound like it is really getting
to max. RPM with the silencer off which would be a
symptom of a blocked exhaust. Something different to
check anyway.

A "Boat House Repair" is one that done without having tools or the skills to do it properly.

[Buccaneer]

Tubs, Thanks for the tip, that I hope to store in the memory bank
for next time. I did have the LU off and do remember scraping
a little carbon at the top of the LU, but not enough to hurt
anything.
Anyway, fast forward to this morning – I put some used J6C’s
in it, and re-synced the mag to carb. Installed the silencer,
but this time left the screen "out".
Started first pull, tuned in the high and low speed, and
it ran nice in all speed ranges. Put the cowls back on,
and it’s all good to go, awaiting a boat ride…. hopefully
in the near future. I left the 56 carb on it.
When I get to it’s Lightwin, I’ll see what happens
with it running my 54 carb.
I like getting things running nice, but it takes the
fun out of it when you’re not sure what was really wrong! 😯

Prepare to be boarded!

[Tubs]

As I remember I took the power head off found the blockage in the leg.
I have a recollection of it narrowing at some point. Been 40+ years ago.

A "Boat House Repair" is one that done without having tools or the skills to do it properly.

[Buccaneer]

Tubs, after you brought up "carbon", and me mentioning
that there was "some" carbon at the power head
base, that got me to wondering if there could be more
carbon further down. I can’t actually remember
shining a light down the leg!
After I give it a good workout on the boat, maybe
I’ll try putting the silencer screen back on and see how
it runs. Maybe a good run will blow the carbon out!

Prepare to be boarded!

[Tubs]

quote Buccaneer:

Maybe a good run will blow the carbon out!

The carbon is a result of the oil of the past.
Todays oil will take much of it out although
the farther you get from the power head the
less affective it is and it does take some time.

A "Boat House Repair" is one that done without having tools or the skills to do it properly.

[Buccaneer]

Finally got the Lightwin carb working correctly.
Ended up drilling out two of the little brass plugs
in the fuel passages, and rodding them out
with a wire, and got the low speed circuit
working again! I cut up a little lead sinker
and tapped it in the holes to seal it up,
then put a dab of loctite on each one for good luck.
So far, so good!

Prepare to be boarded!

[Author]

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