Hello all... long time lurker, first time poster.
I'm not new to glow engines, but I just can't seem to get this one going.
I bought a K&B 7.5 OB off Ebay. Seller says it worked fine last time it was run.
Took it apart and cleaned it up. Looked pretty good inside, but the carb does have a broken off idle fuel needle. It's set at it's last known running position, but the outside part is broken off, so you can't adjust it.
Anyway, using 20% nitro and a pressure tank, I can see that fuel is being pumped/sucked into the carb, and the glow plug gets wet.
The glow plug seems to be working well, and have tried swapping with a known good one.
I'm cranking it (clockwise) with my DeWalt cordless drill and the rubber gripper off my starter (starter wouldn't work, so swapped it onto my drill motor).
The main needle has a flat end. I'm assuming the main needle is not damaged, but really don't know for sure.
I can get it to pop when cranking, and I've tried all main needle settings, but just can't get it to run on it's own. Even has an occasional puff of exhaust smoke.
It's got the Carb that says K&B on the front, with a throttle barrel and stop. The main needle is on the end with the throttle arm, and the idle needle is at the fuel inlet.
Seems to have really good compression.
Some things I haven't tried are: different fuel, replacing carb needles, moving fuel tank closer. Any other ideas?
Is it possible to get vacuum leaks at the bearing seals?
Is it possible the cordless drill doesn't crank it fast enough?
Are these things inherently hard to start?
Any help is greatly appreciated!