Shindaiwa T-20 string trimmer sputtering

[anlrolfe]

Shindaiwa T-20 sputtering when shaft elevated when I trim vines along my fence row. When the "out of position" trouble started I replaced the fuel pick-up line. The pump assy was sticky and I rebuilt the carb at the same time. The trimmer ran great @ H/L 2 1/4 out per factory for the slide style carb. Well now its acting up again. I could only get it to run w/ choke partly activated. I double checked carb settings and tried to dial it in to no avail. I pulled the plug and checked compression @ 120psi after much cranking and throttle wide. This is much lower than expected.

Could the fuel delivery problem be partially caused by vacuum leak?? I'm wondering that if crank seals are leaking lack of vacuum would necessitate use of choke. I know that the impulse line has some part in fuel pick-up.

When I removed the plug I got a limited view inside and the cylinder walls looked OK

 

[alderman]

Check the exhaust screen for plugging just to eliminate that as a possible cause.

 

[anlrolfe]

The screen was "lost" years ago.

I removed the shaft and tore engine 95% down. Ready to split the case when I locate parts. There is lateral motion on crankshaft. Seems like main bearing on output side has noticeable slop. Both must be worn if I can move things in/out. Output side is worse because I can barely feel up/down. I think I'm sucking air past oil seals. Kind of makes sense that sputtering started when I elevated the shaft end.

P&C look good especially considering the age.

 

[Elmore]

I have a vintage 1986 Shindaiwa B45 and a few years ago it would do the same thing when elevated. Since then I have been using Mobil 2 xt synthetc oil in my mix,32:1 and it seems to have cleared up. I can only atribute the change of oil to the improvement.

 

[anlrolfe]

New bearings and seals installed. P&C cleaned up perfect and rod bearings great shape. Got it back together and fired it up yesterday. KT Carb dialed to factory 2 1/4 out and ran better than it has in a long time. All I had to do was a slight idle adjustment. Need to get some smaller line. What I had was way too big and loaded the 20cc RPM's down more than I care for. This is my favorite trimmer hands down!! Closest replacement that I could find local was a RedMax TR2350S and I really wasn't looking to shell out nearly 3 clams until I'd tried/failed at rebuild.