Stihl 044 help.

[huskihl]

If you have the pointed rubber end on your pressure/vacuum tester, you can put the carburetor in place and bend the impulse line over to the right so it misses the carb nipple and tighten the carburetor in place with a wedge shaped piece of rubber or duct tape behind it. That would include the boot and the impulse hose in your test

 

[SteveSr]

I find the best way to do pressure and vac tests is to block the intake with a scrap of bike tire inner tube or plate, stick the blunt end of a suitable size drill bit into the impulse line if needed, and use a spark plug adapter to apply pressure/vacuum.

This way the whole system gets tested and you can push/pull on the AV system to flex all the parts to show intermittents.

 

[mudfly]

I find the best way to do pressure and vac tests is to block the intake with a scrap of bike tire inner tube or plate, stick the blunt end of a suitable size drill bit into the impulse line if needed, and use a spark plug adapter to apply pressure/vacuum.

This way the whole system gets tested and you can push/pull on the AV system to flex all the parts to show intermittents.

I concur with you and @huskihl and @pioneerguy600. I just didn't have the right stuff yesterday. If I didn't think the impulse line and intake boot were important, I wouldn't have specifically stated that they were not included in the test.

 

[huskihl]

I concur with you and @huskihl and @pioneerguy600. I just didn't have the right stuff yesterday. If I didn't think the impulse line and intake boot were important, I wouldn't have specifically stated that they were not included in the test.

Yep. I was just trying to help you out and show you and others that you don’t need a bunch of adapters and fittings to be able to include everything in the test. Everyone wants to poke holes in the rubber so that the bolt holes line up perfectly and purchase adapters for every single saw they test but it’s not needed. A strip of duct tape that’s angle cut narrower on the bottom and wider on top than the bolts can be sandwiched between the carb and muffler and then tightened down will work perfectly

 

[lone wolf]

Pressure test results.

Held vaccum at -10 in Hg for 10 minutes.

Pressure started at 6 psi, bled down to 3 psi after 4 minutes. Bubbling out between the bushing and crank on the PTO side of the case. I did take the clutch and worm gear out so there is nothing pushing in on it to seal. It was originally installed with grease behind it.

2 things to note. Intake boot and impulse line were not included in this test. I don’t have a way to test with those on right now.

Well get it to hold 100 percent.

 

[pioneerguy600]

Well get it to hold 100 percent.

One needs to tighten the clutch down on the bushing for the oil pump drive if it is packed with hard grease that will eliminate the air leak between the bushing and crank when doing a vac and pressure test on the 044 and MS440.

 

[RJTodd]

Pioneerguy600,
I've been following along but am not sure I understand about the oil pump bushing. I haven't torn my basket case saw down yet, so maybe it will make more sense once I get behind the clutch. Is it in any way analogous to the 026? I recently replaced crank bushings in my 026.

Best
Randy

 

[pioneerguy600]

Pioneerguy600,
I've been following along but am not sure I understand about the oil pump bushing. I haven't torn my basket case saw down yet, so maybe it will make more sense once I get behind the clutch. Is it in any way analogous to the 026? I recently replaced crank bushings in my 026.

Best
Randy

026`s do not have the same bushing the 044 has.

 

[mudfly]

026`s do not have the same bushing the 044 has.

The bushing is shown above. The seal rides on the outside on the bushing, but there is nothing sealing the ID of the bushing to the crank which is a leak path unless you put a little grease on the back of the bushing when you install it, then the clutch pushes the bushing tight in and make it seal.

Or this is what I’ve learned. I’m sure others could give you a better description.

 

[LordOfTheFlies]

Since you are able to start I would do it with the bar and chain off, clutch cover off, and grab a can of brake cleaner. Spritz a few times at the spinning clutch while you are holding the trigger to keep the saw alive. If it dies there's your air leak. Do it at the base of the cylinder and also on the flywheel side. If there's a leak it will suck that brake cleaner in and kill the engine.

When you cleaned the carb, did you take out the H and L jets of the carb and put them in the cleaner too? I found this to be the culprit on several saws that sat for years where turning H screw out (ccw) had no effect at all in richening up the mix.

I also had a personal saw sit for a while with truefuel and wouldn't even start and just by opening and closing the gas cap released some built up pressure.

I worked on one saw where a brand new spark plug was leaking. The soapy water trick was very useful in confirming that problem.

I haven't worked on an 044 but I did rebuild a MS460.

 

[LordOfTheFlies]

Another trick is to spritz a little carb cleaner (1 or 2 small squirts) directly into the carb and see if that clears up some blockage.

Also what are you using as a solvent for your ultrasonic cleaner? I fill the tub with water but I bought a set of beakers (50ml, 100ml, 250ml, 500ml, and 1000ml) and fill those with either mineral spirits from a can (for carbs) or naphtha from the parts cleaner tank (for everything else). I also run it for like 50-10 cycles and have the heat on to ensure I get it nice and clean.

 

[huskihl]

View attachment 1052174
The bushing is shown above. The seal rides on the outside on the bushing, but there is nothing sealing the ID of the bushing to the crank which is a leak path unless you put a little grease on the back of the bushing when you install it, then the clutch pushes the bushing tight in and make it seal.

Or this is what I’ve learned. I’m sure others could give you a better description.

That’s an 044 in your pic though, not a 260. The 026 and 260 seal rides directly on the crankshaft.

And yes, in an 036 and 044 that use that bushing, some sealant, grease, or an O-ring in addition to the clutch being tightened down will seal it up

 

[RJTodd]

Thanks for the replies on the 026 vs 044 seal. The picture was worth the proverbial 1000 words. . .

 

[Mad Professor]

That’s an 044 in your pic though, not a 260. The 026 and 260 seal rides directly on the crankshaft.

And yes, in an 036 and 044 that use that bushing, some sealant, grease, or an O-ring in addition to the clutch being tightened down will seal it up

No bushing on an 036/360

 

[huskihl]

No bushing on an 036/360

View attachment 1052282

Been awhile. I was looking at #14. Maybe it’s the brass oil worm bushing

 

[Mad Professor]

Been awhile. I was looking at #14. Maybe it’s the brass oil worm bushing

View attachment 1052325

Yep. It's steel. There is a washer behind the bushing #11

 

[mudfly]

UPDATE to the pressure and vac testing. I was able to get the spark plug adapter so I can test it together. After a few issues with getting the everything sealed, it’s holding 10 in Hg and 5 psi for 10 minutes.

Probably have it narrowed down to the carb, unless something was leaking before that isn’t now.

I currently have the Zama carb. I guess I’ll go thru that one more time and see what happens.

 

[lone wolf]

UPDATE to the pressure and vac testing. I was able to get the spark plug adapter so I can test it together. After a few issues with getting the everything sealed, it’s holding 10 in Hg and 5 psi for 10 minutes.

Probably have it narrowed down to the carb, unless something was leaking before that isn’t now.

I currently have the Zama carb. I guess I’ll go thru that one more time and see what happens.View attachment 1052445

View attachment 1052446

Get OEM not knock off

 

[SteveSr]

UPDATE to the pressure and vac testing. I was able to get the spark plug adapter so I can test it together. After a few issues with getting the everything sealed, it’s holding 10 in Hg and 5 psi for 10 minutes.

Probably have it narrowed down to the carb, unless something was leaking before that isn’t now.

I currently have the Zama carb. I guess I’ll go thru that one more time and see what happens.

Zama's are known for dodgy / leaking main nozzle check valves which will cause exactly the issue that you are seeing. If the valve doesn't close completely it will cause an internal air leak and the saw won't idle.

This is a non-repairable fault unless you can find a replacement nozzle and have the skill and patience to pull the old one out and press a new one in.

 

[lone wolf]

Zama's are known for dodgy / leaking main nozzle check valves which will cause exactly the issue that you are seeing. If the valve doesn't close completely it will cause an internal air leak and the saw won't idle.

This is a non-repairable fault unless you can find a replacement nozzle and have the skill and patience to pull the old one out and press a new one in.

Certainly worth a try if available.