044 problems

[mudbug660]

New here. I inherited a 12mm 044 a few years back and it has always given me fits. S/N 143 770 515
I’ve put in a carb kit still acted up then a knowledge gentleman I know put in another one and same thing. Cranks up, runs fine, starts getting warm warm and the idle gets erratic. Have to keep bumping the throttle so it won’t die. Removed the carb limiters and adjusted low and then high with a tach. Did fine until it got warm again then same thing. Today I check compression with a non-small engine tester (I know I know but that was what O’Reillys had). Got 150 psi cold. Ran it without a load for 3 to 5 minutes and tested again and got 130 psi. While running I sprayed it down with carb cleaner at gaskets, crank seals and boots with no change in idle.
Stuck a boroscope in the exhaust port and spark plug port. I’m not real sure what is good. Piston seems rough. See video links below.



I’m going to do some cutting tomorrow and get it nice and hot until it acts up again then compression test it again. What else do I need to check?

 

[BangBang77]

Pressure and vacuum test is the first test I do if I can't get a saw to tune.

Was the carb kit OEM? How old is the fuel filter? The fuel line? The impulse line?

 

[Yukon Stihl]

Dont use that saw till you fix it.
The piston is severely scored.
First a vacuum and pressure test needs to be done to see why the piston got scored.
It's a great saw and worth repairing.

 

[scallywag]

I’m going to do some cutting tomorrow and get it nice and hot until it acts up again then compression test it again. What else do I need to check?

Don't be doing any cutting with that saw until its seen a Doctor!....Piston looks like its already been plenty hot enough!

 

[SEAM]

You are looking at a fairly cheap fix at the moment. One more lean and hot condition might double or triple the cost of repair.

 

[joe25DA]

That looks like more damage than an air leak/lean condition would cause. She looks straight gassed

 

[mudbug660]

Impulse line, fuel line and filter hasn’t been replaced while I’ve had it. Carb kit was non-oem.
I’ll do a vacuum test this morning, order impulse, fuel line and filter.
Do I need to go ahead and buy a meteor piston with caber rings or wait until I dig into it?

 

[lone wolf]

Impulse line, fuel line and filter hasn’t been replaced while I’ve had it. Carb kit was non-oem.
I’ll do a vacuum test this morning, order impulse, fuel line and filter.
Do I need to go ahead and buy a meteor piston with caber rings or wait until I dig into it?

Wait.

 

[pioneerguy600]

It will need a new piston but best wait til the cylinder comes off and see how much damage it has. If its not deeply gouged then it can be cleaned up and reused. The Meteor pistons I have used lately on the 044`s have been getting worse for deck height, the one I was looking at last evening is .024 lower than the OEM pistons making a large squish area if a base gasket is used. The piston fit the bore nicely bu at .045 squish a lot of power is being lost.

 

[joe25DA]

I wouldn’t run that saw with that top end. There’s a small chance you could clean it up with muriatic acid and a fine sanding then rings. But your will have to pull that jug. Seals, intake boot and pulse line alone will not fix the damage. That’s a real good saw. Worth putting money into. I just had a 2171 Jred. Identical damge. It was straight gassed from the fired department and hardly used. I didn’t mess around. Put a brand new 372xp top end on.

 

[mudbug660]

Vac test.

Sheet metal on carb side with grease on sealing surface then carb bolted down.
layer of duct tape on exhaust with muffler bolted back down. 13 seconds to leak down from 15 inches mercury to 10 inches of Mercury.

 

[mudbug660]

I think we’ve got a winner. I’ve about to take the cylinder off. I inspected the clutch side seal and it was good with no leaks and no slop

 

[mudbug660]

Exhaust side
Intake side

Exhaust


Intake side

Feels pretty smooth for the most part. Worst is on the side of the exhaust on the clutch side of the port.
It’s the only thing that you can feel with your finger nail.
Plan going forward is to try and wet sand the problem area and get some muriatic acid and clean some more and see how deep it went into the nikasil.
I’ll hold off ordering parts until after we see how the cylinder is

 

[pioneerguy600]

Exhaust sideView attachment 894383
Intake side
View attachment 894385
Exhaust
View attachment 894386
View attachment 894387View attachment 894388
Intake side
View attachment 894390
Feels pretty smooth for the most part. Worst is on the side of the exhaust on the clutch side of the port.
It’s the only thing that you can feel with your finger nail.
Plan going forward is to try and wet sand the problem area and get some muriatic acid and clean some more and see how deep it went into the nikasil.
I’ll hold off ordering parts until after we see how the cylinder is

Good plan.It does look like it will clean up, just make sure to get all the smeared aluminum off, test with acid and if it does not bubble/fizz then its plating. Sometimes there is a darkened stain on the cylinder plating, if its not aluminum residue then it won`t hurt anything. Looks like it was ran lean, air leaks will cause that.

 

[kyle1!]

Make sure none of that crud falls into the crankcase. Next time clean the saw before disassembly.

 

[motorhead99999]

Make sure none of that crud falls into the crankcase. Next time clean the saw before disassembly.

I leave it in there to plug up my crank seal leaks

 

[mudbug660]

I’m thinking it’s wore through the nikasil. Any way to tell for sure? Would transfer be that uniform?

 

[scallywag]

I’m thinking it’s wore through the nikasil. Any way to tell for sure? Would transfer be that uniform?

If the plating is worn through acid will react with the cylinder casting in that area.

 

[albert]

If the plating is worn through acid will react with the cylinder casting in that area.

 

[mudbug660]

Still bubbling