026 carb help

[Jake Dykstra]

This is my nephews 026.
So I've replaced the fuel line and filter. Impulse line. Cleaned the carb real good see no issues with it.
Problem is it still wants to die when tipped forward. I assume fuel is puddling behind carb and causing a rich condition thus lowering idle speed and eventually it dies.
Turning saw left or right idle is constant.
I put the carb off my 026 on it and problem persist. Put carb back on my 026 and works great.
Sprayed break clean all around crank seals and base gasket and no change in idle.
Turned in L screw until it barely runs and it's a little better but still lowers rpm and wants to die.
Anybody have some great tips or tricks that are currently not in my cerebral arsenal I would love to here them.
Thanks

 

[Junk Meister]

SO IF the carb From your 026 acts up on the nephews saw but runs proper (Again) when back on your 026 doesn't that almost if not eliminates the issue being something other than the carb. I would do a vac/press test and have the flywheel and oil pump removed to get a very good visual when testing. I am favoring the problem as the seals not sealing good enough and compromising velocity to keep everything in harmony. in simpler words you are catching this saw before damage is done.. Did you pull the muffler to inspect the piston and cylinder? Also when vac/press testing don't forget to rotate and give the crankshaft a bit of endplay to see if the seals are really holding good. case gaskets can deteriorate and sometimes a dunking under pressure will reveal a leak. good luck keep us informed.

 

[Junk Meister]

Turning the L screw in is restricting fuel flow so minimizing the supposed puddling in intake boot. Some one will jump in and set me straight or get you on track but the age and reputation of the 026 seals usually prevail.

 

[Jake Dykstra]

Piston looks good. I had the top end off and inspected, cleaned then glued it on.
I'll get it press/vac next. Had heard these saws can be a little prone to this problem so I wanted to check with ya'all thinking there may be something I'm missing.
Thanks for the reply

 

[drf256]

Did you try running it without the air filter?

A very common problem is the spring in the AF wearing and the choke flap intermittently getting pulled closed.

It is true that there is a lip on certain cylinders that makes them prone to puddling. The only remedy is to match it to the boot.

Try no airfilter first.

 

[trooney]

Not that this is your problem, but it might. Had an 026, passed p&v. Replaced everything I could and it would still want to shut off if I tipped it any at all. Drove me crazy. Somebody suggested that I replace the seals. I balked at that because it passed p&v. They suggested that I turn the crank while p&v testing and I'll be dammed it was one spot on the seals that was not sealing, as was mentioned above. Replaced seals was good to go. Seals are relatively cheap, it all depends where you get them. If the seals haven't been replaced for a while, I'd replace them. You're probably going to have to do it eventually anyway.

 

[Gord]

Just did one and did put new seals in it because of it's age but the biggest issue of it not runnig right was the pulse line was too short where it goes int the carb, replced it with one that had a longer chunck of rubber on it and did rebuild the carb as well and hold 15-20lbs all day long and also did ease the muffler out, the do sell a differen't front plate for it with a vent in it meant for a 026, that has amazing performance

 

[Jake Dykstra]

I'll have to try the longer pulse line. I have replaced it with a new one and thought it looked short as well. Which model did you use the longer pulse line from?
It has an air leak somewhere at the back of the carburetor. When I spray brake clean in that area it dies right away. I was very careful to only spray directly behind using the straw. I thought maybe it was the carb manifold auction but have replaced the manifold with no success.
Even made a gasket to fit between and Still dies with brake clean.

 

[Jake Dykstra]

New seals in. Longer pulse line on.
Starts up great almost too quick. Seems like it's getting plenty of fuel.
Sounds great on start up. Idles great for a minute or two and can tip it forward with no change in rpm.
After it warms up for a couple minutes I can Rev it up and down and sounds good but when I tip forward it dies.
Grrrrr

 

[beaglebriar]

Did you run it without the filter as Doc suggested??

 

[Jake Dykstra]

Did you run it without the filter as Doc suggested??

Yep

 

[Canadian farm boy]

Inspect the intake manifold real close

 

[Jake Dykstra]

Inspect the intake manifold real close

Just put new manifold on. Also made a gasket between carb and manifold to make sure it was sealing.

 

[Jake Dykstra]

Also this saw has a lot blow back through the carb. Not sure if it is causel or related at all.

 

[Canadian farm boy]

Just put new manifold on. Also made a gasket between carb and manifold to make sure it was sealing.

Do you have the manifold sleeve and the surrounding ring on? You shouldn’t need a gasket especially with a new manifold

 

[Jake Dykstra]

Do you have the manifold sleeve and the surrounding ring on? You shouldn’t need a gasket especially with a new manifold

Yeah everything is there. Just figured I'd make sure it didn't leak.

 

[beaglebriar]

Are all the rubber bits oem or aftermarket??

 

[Jake Dykstra]

Are all the rubber bits oem or aftermarket??

Yes all oem.

 

[Jake Dykstra]

Update and thanks:
After replacing damn near everything! (Which isn't a bad thing as most the rubber parts were getting spongy
and crank seals is cheap insurance)
I decided last night to try my 026 carb on it again and viola it runs great.
Figure it was a couple things going on as I put my carb on previously and it seemed better but not 100%.
Anyway put a new carb on and it runs just peachy.
Decided to rebuild the old one and try it on my 026 just to prove to myself that it was (at least one of the issues)and it's still problematic.
Thanks for all the replies.

 

[drf256]

Could still be the dreaded lip on the intake snout. I’ve seen it mostly on the newer 44mm decomp and ND jugs. Less on the old style.

Ive had some head scratchers for sure where nothing but fixing the lip cured them. Some hot ported ones responded to a different coil, I know it makes zero sense. If the timing is advanced with certain coils, the L setting needs to be richened to the point where is causes more puddling to occur.

If the problem persists I’d pull the jug and match the snout to the boot. You can add a groove to it as well. Many of us that have been around a few saws have noticed that Stihl added this to some models. The late 361 is a perfect example. There is a factory space between the lower boot and the snout with a drain hole. I believe the 261 and 462 have the same. The 036 (not the earlier 034S) have a V in the bottom of the intake port to remedy The puddling issues.

I guess my point is, even if another carb fixes this pesky problem, it may not be the carb.