idle fast and slow

[lugo2214]

Hello;
got a YM2500 with a re-built engine and the shop cant get it to idle right. it turns on and it idles normal , then goes fast for a few seconds and then it slows down all without throttle movement.

they have gone thru the fuel pump adjustment according to the YM manual thet I provided them and are telling me now to replace the pump.

It did not do this prior to the repairs........

HELP??????

 

[HoyeTractor]

My money would be on a sticking or binding governor linkage. Could also be a sticky injection pump rack. There is a lot that actually goes on to maintain a steady idle. The governor is frequently adjusting the throttle up & down. A sticking linkage or rack causes those adjustments to become very noticeable.

Aaron
Hoye Tractor Parts
Contact Us
(940)592-0181

 

[deepNdirt]

Hello and Welcome......
I know this will sound like a dumb suggestion.... but has the fuel lines been bled free of air ? some times it can be the simplest of things, I let mine run out of fuel once and even though I bled the lines to what I thought was good I still had what you are describing high/low idle. I know it didn't do this before it ran out, I kept working with it timing it to just before it started to idle down then I would crack the bleeder valve the air was for sure there and purged out in bubbles, it took about 3-4 more times until I got it all out, idles fine now. i won't let the fuel run out ever again
again this is only a question/suggestion