038AV super running rough need help quick

[stihltech]

Follow the fuel. Vent open, new fuel hose and filter.clean the carburetor. Pay attention to the inlet screen, condition of diaphragms and inlet lever hieght. Put in fresh fuel. If there is still an issue move on to a vaccuum and pressure test. No test tools? Get some brake clean with a nozzle and spray around all rubber parts and seals while running. Any change will indicate a leak.
Good luck and report back.

 

[Woodslasher]

Look at the picture

It's on the clutch side, next to felling spikes, not fylwheel side

I am looking at the picture, and typically the oil tank extends to both sides of the crank case, so the crack is still in the oil tank.

 

[Mad Professor]

yes it’s a crack in the front of the oil tank. I’ll attach a better picture. Would you fill it in with JB weld? Or just leave it as is?

OK my bad thought it was CC break. If it is leak you want to live with? JB might fix it, but better get all oil residue off first.

See if saw is worth a case.

I'm ~150 miles away in S Vt

 

[EKreider89]

Reporting back, I took both the 038 and my 026 and it was really the maiden voyage for both of them. The 026 way outperformed the 038 until it busted a AV buffer (it was already partially tore). I think the 038s lack of performance was largely due to my lack of experience in tuning and adjusting carbs. I’ll keep messing with it and see if I can get it to run stronger. I’m having trouble all over the board, not idling well, not smooth acceleration and not tons of power at full throttle. Is there any performance upgrades on a 038 that are essential?

Thanks guys for all the help so far

 

[Bob Hedgecutter]

Reporting back, I took both the 038 and my 026 and it was really the maiden voyage for both of them. The 026 way outperformed the 038 until it busted a AV buffer (it was already partially tore). I think the 038s lack of performance was largely due to my lack of experience in tuning and adjusting carbs. I’ll keep messing with it and see if I can get it to run stronger. I’m having trouble all over the board, not idling well, not smooth acceleration and not tons of power at full throttle. Is there any performance upgrades on a 038 that are essential?

Thanks guys for all the help so far

Have you taken that muffler off yet and taken a look at the piston?

 

[EKreider89]

Have you taken that muffler off yet and taken a look at the piston?

Yes I tore it all down the other night. Piston and cylinder both look really good. I don’t have a compression tester yet to be able to test compression

 

[stihltech]

Mechanical condition first. I never use a compression tester. What's inside is more important.

 

[ROME K/G]

Change the spark plug!

 

[EKreider89]

Mechanical condition first. I never use a compression tester. What's inside is more important.

Everything looked good from my knowledge. Again I’m not an expert. I was gonna check the vent hose next. It’s got a new fuel line new fuel filter and a new spark plug

 

[Mad Professor]

Everything looked good from my knowledge. Again I’m not an expert. I was gonna check the vent hose next. It’s got a new fuel line new fuel filter and a new spark plug

Not Chi-Com ****?

Vent you can use tygon, push not screw the grub screws in.

 

[ROME K/G]

Everything looked good from my knowledge. Again I’m not an expert. I was gonna check the vent hose next. It’s got a new fuel line new fuel filter and a new spark plug

ok

 

[EKreider89]

Are there good resources via books or the internet for properly tuning a carburetor?

 

[ROME K/G]

For the Stihls I first set them by the manual, turn screws in then 3/4 out and then fine tune from there, adjust low mixture then high, saw should be at operating temp.