Stihl 076av rebuild

[jake wells]

There is not much more to say than this

oil leak haha

 

[jake wells]

you running 5:1 mix??

 

[Brewz]

Ha ha, yeah bar oil goes great at 5:1

 

[Lee H]

There is not much more to say than this

Sounds great and nice project but i never run my saws on a concrete floor.
Pounds the chit out of them and wears the bottom of the saw.

 

[Brewz]

I have had trouble getting it to run properly at times, and today I went looking for the air leak.
I had my suspicions it was in the oil pump worm gear area as I had bought an oil seal from the local bearing supplier to fit into it.
I was right!
The seal I bought had become heat effected and no longer stayed in the worm gear. It basically fell in and out.

I dug out the new worm gear I had purchased and found it is undersized and wont push over the crank shaft.
My heart sank..... I thought, where the bloody hell am I going to get a new oil seal with a metal case to fit this worm gear.

I got to thinking and figured manufacturing companies tend to re-use common parts between models.
I was right.
The worm gear oil seal is the same size as the 064/066 short case small crank flywheel side oil seal, and I have 3 of them

Went in and worked great!

 

[Brewz]

Well, that didnt fix it.
Used it today and its worse so I have disturbed something.

I am thinking its the worm gear its self, being a bit worn inside and out is moving around making the 2 x seals that ride on it leak.
Going to pop the seal from the new one I have and try and sand it out evenly so I fits nice on the shaft, then fit a new seal.

Its starting to *s-word me off........ I have a lot of time in this thing and still no result

 

[jake wells]

sometimes i feel the need to take a shotgun to items that piss me off

 

[Brewz]

I am determined to make it work again.
It is definitely an air leak, and it changes every time I make a cut.
One second its idling at 4000 rpm, next its rich stalling when it seals.

Its got to be that worn worm gear.

 

[Brewz]

This f@#king thing is driving me mad!

It runs fine until it gets hot, then idle speed will increase to 4000 rpm
It will sit there till I feed it a bit more (1/4 turn) fuel on the L screw and it drops back to idle.
Wind back the L screw to where it was and give it a bit of a rev and it does it again.

Today I checked the worm gear and it looks fine. Ran it with the clutch drum off and it didn't blow bubbles when I hit it with WD-40 at idle. It could still be sucking though i guess?
I also stripped the intake tower and checked everything. I made new gaskets.... again..... and it made no difference.
blanked off the flood governor on the carb
no difference

I am after ideas

I am thinking air leak but it could also the carb

 

[jake wells]

you check the throttle shaft for wobbling or play? it could be a worn out carburetor.

 

[Brewz]

Yeah I thought about that but why does it only play up as it gets to running temperature?

 

[Brewz]

I realized today I have never checked compression.

Not bad for a 111cc saw with only 1 tank through it so far

 

[Lightning Performance]

If your still chasing that gremlin stop looking at where you have been. Go where you have not been. Any carb that is known good and will fit somehow might be your next move. Some carbs just plain *f-wording dog *s-word sometimes. Pull hair, bang head, bang head again. rinse repeat ...

 

[Brewz]

Fairly sure I just found the issue.

The throttle linkage on the carb butterfly shaft was loose, allowing the butterfly to move a bit when it should have been closed at idle.

I pulled the shaft and tried to give it a tap with a center punch to get it to grip but muffed it and....... Well........ I now need a complete new shaft.

Anyone know where I can get spare parts for a walbro WS26 that will post internationally?

 

[Brewz]

Fixed and going back together

 

[TPA1]

I have an 075 with that exact same gremlin. When you find it, you will probably save me a world of trouble.

BTW, I can't tell you how many times I inspected, reinspected, pressure tested, and changed the worm gear seal because I am/was certain that it was the problem.

 

[jockeydeuce]

Fixed and going back together

Throttle shaft obviously made it's way to the other side of the world ok??

 

[Brewz]

Throttle shaft obviously made it's way to the other side of the world ok??

Yes mate it did.
I fitted it up and took it out to give it a run, confident it would be fixed.

Is still has the problem.

Once it gets hot it gets a lean revving thing happening all by its self, and I am talking 4 or 5000 rpm.

Its really browning me off!

I have a mate who has a couple spare carbs that we are going to try on it and failing that, its getting blanks made, preasirized and dropped in the pool

 

[jockeydeuce]

Hang in there...There has to be a reason for that. Without sifting through the whole thread, have you vac tested the saw?

 

[Brewz]

No and I dont have a vac tester.

THE OIL PUMP!

It just came to me!

The oil pump is a long thing that pushes into the case and is driven on the internal side of the crank seal.
I think I will pull it out and check it. I replaced the rubber seal but who knows.
I see oil resistant silicone in its future.