C bar

I got a used of a gpx4 I'm trying to tune this stock engine. When I start the engine it will not idle the rpms wil go up then come down to normal then go back up without messing with anything. Seems no mater what I twek the engine will not idle. There is a small cut in the exhaust couple could that do it? Any help would help.

Bundy_Bear

iTrader: (11)

Yes replace the exhaust coupler, also add a rubber band on your carby to close the carby as a fail safe. I have had a few HoBao engines that the carby action wasn't smooth causing me issues. Some people have replaced the carby to a Novarossi one as a solution and this has also helped with tuning. But remember this is a cheap engine so don't spend a heap of money trying to get it too run.

Andrew