Husqvarna 142

[JT78]

Ok so had somebody give me a free husky 142 it needed some TLC I replaced the bearings and crank seals rebuilt the carb put in a new ring and put a muffler back on it. So the saw now runs fairly well but something isn't quite right and I'm not sure exactly where the issue is but I think it's an air leak around the impulse line or intake.
The saw will run rich one time you rev it and lean the next it also changes while you are moving it around a lot limbing. Any ideas how I can stop the leak around the impulse line and intake or what else would cause this?

 

[psuiewalsh]

Could you try some motoseal to test your theory

Sent from my XT1585 using Tapatalk

 

[1990Husky262]

Have you pressure tested it?

 

[JT78]

Have not pressure tested it so is motoseal basically like silicone gasket material? I usually just use the red silicone I use on my vehicle engines.

 

[1990Husky262]

need to use gas resistant sealant. Red silicone is not gas resistant. Impulse nipple is real common to split on those and probably is the problem and will need to be replaced. Then use a good fuel resistant sealer like Yamabond, motoseal or equivalent and lightly apply inside intake pipe and lightly around outside of impulse nipple and a little on pipe that sticks into impulse nipple being careful not to block impulse hole. Once together i usually clean excesses squeeze out from inside intake manifold and make sure impulse passage did not get blocked and then allow to cure good before starting.

A least that's how i do it. If the impulse is split then really all u have to do is replace it and the reassemble but i like to add the sealant to really seal things up good plus adds as a lubricant to help thing slide together good. You have to be careful on reassembly to make sure you don't fold intake and align impulse pipe into nipple and the sealant just helps things to slide together. Just remember don't need to gob on the sealant just takes a little.

 

[JT78]

The impulse was split I replaced it when I put it back together but I think it's still leaking from there.

 

[JT78]

Good info about the motoseal never realized the red rtv wasn't fuel resistant.

 

[1990Husky262]

if you resealed your engine pan with the red that could very well be your problem. If you have the ability to pressure test the engine that will tell you were to go if its an air leak.

 

[JT78]

It's not too hard to just tear it down and rebuild it again I will use some motoseal this time.

 

[Landmark]

If you have the ability to pressure test the engine that will tell you were to go if its an air leak.

+1

 

[JT78]

It's funny I've been working engines for a long time but have never gotten a pressure gauge and don't have anything made to block off the ports. I do have a vaccum gauge but have never gone through the trouble of setting it up on a chainsaw mostly just used it to set carbs on car motors.

 

[1990Husky262]

Pressure/vacuum tests are probable on of the best most important tests you can do on a two stroke engine to isolate problems. Would be a wise thing to get set up with if you plan on playing with saws. It can make problems that would normally make you pull out your hair easier to diagnose. That way you know if you have an air leak for sure and not chasing some type of carb problem. The way i block off the ports is i take a piece of rubber like a piece of inner tube and cut it out like a gasket but leave it solid in the center then remove the muffler and carb and install the rubber and then reinstall the muffler and carb and tighten down. You can also cut the rubber in a wedge shape and just loosen muffler and carb and slide rubber wedge in and then tighten down. Then you need some type of connector to thread into spark plug hole to add pressure/vacuum. I use a piston stop i bought from husqvarna that has a nipple built into it and there are other adapters available. I have also seen people that take a spark plug and knock out the porcelain and epoxy in some type of fitting. Then i take my mighty vac vacuum/pressure pump and pressurize to 7-10 psi and pull 7-10 in of vacuum and make sure it holds for at least thirty seconds. If not pressurize and spray with soapy water and look for bubbles. If it leaks under vacuum you can spray some wd40 or drip some oil around leak points and see if it sucks in. It is also important to do both a pressure and vacuum test because some times you will not leak under pressure but leak under vacuum or the other way around.

 

[JT78]

Well tore the saw back down today and reassembled with motoseal also around the impulse and it runs great now idles a little high but that probably has to do with how I changed the ports it revs like it's being fed crack can't wait to see how it cuts.

 

[Adirondackstihl]

I got one on the bench right now that won't "pop" but every once and while.
Has spark, getting fuel. compression is good.

I thought about the possibility of an air leak.

What's the impulse set up look like on these orange Poulans?

 

[Motorhead]

The carburetors are real sensitive,could be either too much or too little fuel.My guess metering needle.

 

[Adirondackstihl]

The carburetors are real sensitive,could be either too much or too little fuel.My guess metering needle.

I checked the screws, they are the EPA splined screws. My customer isn't smart enough to fabricate something to turn them with.
So I counted like 2.75 turns on L & 3.25 on H.

I tried every conceivable (within reason) carb adjustment.....with no luck.

I haven't gone past taking the air filter off this thing yet as I don't wanna spend a lot of time on it

 

[Adirondackstihl]

Anyone know where the screws need to be set at......exactly.

This thing looks brand new.
My customer bought it from an older man where I'm sure it sat with pump gas in it.
But he has ran it flawlessly for the last 2-3 weeks. Then, outta the blue, he said it started to idle up.

 

[Motorhead]

The ones I've worked on that sat for a long time mostly needed new fuel filter and fuel line,

 

[Landmark]

I have one that i got from a old man. It had t even had a tank threw it and sat for few years. I tried with no luck cleaning and adjusting the oem carb. I ended up puttin a new carb and fuel filter and it runs great. And if sombody steals it out of my truck tool box i havnt lost much.

 

[Adirondackstihl]

I have one that i got from a old man. It had t even had a tank threw it and sat for few years. I tried with no luck cleaning and adjusting the oem carb. I ended up puttin a new carb and fuel filter and it runs great. And if sombody steals it out of my truck tool box i havnt lost much.

Yeah
I had the customer order a $12 Chinese carb for it to see if that's gonna be any better.