Originally Posted by
LONGREDDOG
Well. I've gotten a lot of good advice here on this thread so far, maybe you can help with something else.
When I took off the piston the crown has a lot of very brunt on carbon. I had to scrub (with a scrubbing pad) and soak in a cleaner in order to locate the small mark that shows which end to press out the wrist pin.
I had tried to scrape it off with a wooden stick, but that did not do a thing.
The bottom of the contra piston is also covered in the same hard black mess. Is there any EASY chemical or other method of removing it?
I don't want to dismantle the engine any further if I can help it. Should I just leave it alone and run it as it is?
Thankyou, Ed Stout
i
Ed,
PAW advise to just scrape the stuff off the piston top with a hobby knife blade. There are chemicals available for cleaning but I'd be cautious risking your valuable piston fit by using them. I'd also be inclined to not worry about the stuff on the contra piston. Once you get it running with good fuel, PAW suggests that carbon buildup won't be a serious problem, most of it it'll blow out the exhaust. That's also my experience. It's ok to clean it off if you ever have to remove the contra but otherwise it's too much trouble on a well running engine.
I have quite a few of the .15 TBR GTS PAWs which share many components with your .19. They're great engines with an ultimate power almost reaching Nelson standards.