1955 3hp lightwin...burning smell and high speed stutter

[jonoman69]

Hey just recently fixed up a little 3hp lightwin. Motor works excellent used it a few days in a row now and idles around perfect. Yesterday comming back in from fishing had it opened up then it started stuttering st wide open and a rubber/maybe electrical burning smell and some smoke came from the case. Turned it off started it back up...the burning smell and smoke stopped still idles fine but when I open it up it starts to do the high speed stutter i want to call it. Just thought I'd get ur guys thoughts before I tear into it. When I fixed it up I only replaced one coil and neither of the wires....thinking maybe a coil or wire burnt up and when its opened up its throwing the spark to early and messing with the timing???

 

[Crosbyman]

pull the flywheel and inspect wiring look for burns or cracked coil

run it in the dark look for arcing

 

[F_R]

Checked the obvious? Water pump? It shouldn't be smoking.

 

[F_R]

While you are in there, check the water tube. They are notorious for getting bent and rubbing on the spinning drive shaft, which wears a hole in the tube, allowing water to spill out without ever reaching the powerhead.

 

[jonoman69]

I'll double check but am I quite positive it's still spitting out lots of water....

 

[jonoman69]

Yup it is deffisntly pumping lots of water. Still starts and runs fine other then wide open does a fast stutter every now and then. Heck the coils when I get home one of then is old for sure must have been the burning smell and smoke I guess

 

[Crosbyman]

for sure ??? just smell it
https://www.ebay.ca/itm/Ignition-Co...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

 

[Chinewalker]

Check the exhaust cover that the plug wires aren't resting against it. The exhaust cover on those isn't cooled, except for the very forward edge. They can get pretty hot, and if the plug wires are directly touching the plate, they can melt.

 

[jonoman69]

I'm positive its pumping lots of water nice spray st idle and opened up its gushing it out. Smell what
?? Also I thought I read somewhere you have to use vertices spark plug wire figure mise well replace that as well.

 

[F_R]

They WILL spit out lots of water if there is a hole in the water tube. But that water is not going through the powerhead. Not saying that is the problem, just pointing out the possibility.

An old coil is also an obvious possibility for the stuttering, but never saw one smoking.

 

[jonoman69]

Specific wires I meant to say.

 

[jonoman69]

The smoke was coming from under the covers and it was a burning smell......how do they spit out lots of water from the exhaust port of it's not going through the powerhead?

 

[Lightwin 3]

The smoke was coming from under the covers and it was a burning smell......how do they spit out lots of water from the exhaust port of it's not going through the powerhead?

The water pump. (impeller) is still pumping. The leak fills the exhaust housing.

Does the head look like it got hot? Burnt paint, etc?

 

[oldboat1]

There may be a screw up at the top of the leg, just under the powerhead (left side looking at it from the rear/prop). The screw looks like a drain screw you find at the gearcase. If you remove it, you should get a strong stream of water with the engine running. It's difficult to get at the powerhead to check temp, but you should be able to touch without getting burned (I check the temp of the housing at the bottom -- find that runs warm, not hot, when the cooling is correct.)

Take off the side covers at least to see if you can locate source of the heat. Plug wire against the exhaust cover sounds like a good possibility, as Chinewalker mentioned.

 

[F_R]

The smoke was coming from under the covers and it was a burning smell......how do they spit out lots of water from the exhaust port of it's not going through the powerhead?

Water tube goes up through the exhaust housing to get to the powerhead. But if there is a hole in it, the water just spills out the side of the tube and blows out the exhaust relief holes, deceiving you into thinking all is fine.

 

[jonoman69]

So here's some pics of the head. And I know the color of it is off but the head gasket doesn't look burnt at all and as far as I can remember the head was already the color it is as I'm sure it being a 55 it was probably over heated a few times lol.

 

[jonoman69]

And as far as the plug for the water pump I've tried getting that out before to check water flow qomt budge...dont wanna bust it

 

[F_R]

That is a Johnson head on an Evinrude motor. And that is an unknown aftermarket head gasket.

 

[jonoman69]

It's a sierra head gasket. Didn't know it was Johnson head......but doesn't look overheated to me correct

 

[Crosbyman]

smells what ? burnt rubber... burning paint....burning oils

have you pulled the flywheel to inspect underneath ??