degray

My Feedback: (15)

My 140 quit shortly after take off resulting in damage to the engine as follows: High needle bent, carb to head inlet pipe dented and slightly out of round at the carb end, exhaust header rotated to max limit which resulted in creases in the teflon tube between header and pipe. Engine hit on spinner, prop not damaged.
Replaced needle and inlet pipe and repositioned header and removed the two creases in the teflon tube. Fuel clunk is fine. When I initially test ran the engine after the crash, it started fine and run up and idle were also ok. However, if the engine runs for a few minutes, it sounds like it could be lean. Richening it up does appear to help but not for long. I checked the exhaust system, hand cranking while holding finger on end of pipe and it holds pressure fine. The bottom line is that the power is only about 30% or so at full throttle. Don't recall this being the case when it quit on takeoff.
I was planning on leaving for a contest this Friday and would really appreciate and suggestions you guys could offer. Sorry to be so long but felt that some of the information may help your analysis. Thanks, Don

petec

My Feedback: (58)

Did you check the crank for run-out? If it hit hard enough to cause a dent on the back of the engine it may be damaged and causing problems once everything heats up.

degray

My Feedback: (15)

I don't think it hit that hard, but I have a dial indicator and will check the crank runout. Also, I mentioned that I replaced the HS needle, but with a used one I borrowed from my 110 (same YS part #). Did not replace the needle seat. I noticed today that the used needle has a small rub ring around a point about 1/8 in from the tip. Can't feel any roughness or grove and don't see anything using an eye loop. I now have a new HS needle assemply complete with O-rings and plan on installing it. Perhaps that could be part of the problem. Any thoughts? Thanks again for your suggestion. Don

petec

My Feedback: (58)

If you had a long extension on your HS needle it will wear and also wear the seat. Check the crank and put the new needle and seat in. Also make sure all your o-rings around the push rod tubes are in place properly, valve cover gasket is OK....you know the usual suspects.

Bustabloodklaart

Sounds like a leak in the plumming somewhere to me.
I'd you haven't already done so, I'd renew all the tubing.
Best of luck
John

degray

My Feedback: (15)

You were correct, it was the in the high speed needle assembly, most likey the seat. I replaced the entire assembly, needle, seat and O-rings. The problem has gone away. Thanks again for your help.

petec

My Feedback: (58)

Don,

Always glad to help and nice to meet you at D1-D2 Shootout.

Pete

degray

My Feedback: (15)

Same here Pete, thanks again for all your help. Have shortened the needle extension and I'm building a stronger nose ring. Don