OverRev

[georgiaborn73]

I just rebuilt the carbs on my 1985 70hp prop Yamaha. The tach is broken but soon to be repaired-hopefully. When starting the engine at idle it revs to WOT depite the throttle setting. Manually pressing the throttle to idle on the block doesnt seem to help either. Any ideas?

 

[fish4970]

Re: OverRev

double check the gaskets you may be leaking / sucking air

 

[georgiaborn73]

Re: OverRev

thank you will do. I just put new gaskets on. Any other ideas on this?

 

[fish4970]

Re: OverRev

did you sync the carbs after you re installed them<br />remove the air box and see that the butterflies <br />are all the way closed on all carbs<br /><br />it dosent take much of an opening to rev a 2stroke<br />with no load on it

 

[georgiaborn73]

Re: OverRev

yes i did that, the mechanic that cleaned the carbs was a mower mechanic but previously worked on yammy carbs for generators and bikes. He gave me a 7mm wire and said the butterflies should have that 7mm space/gap between the edge of the valve and intake throat when in the closed position. Might this overrev have anything to do with the pilot screw? The manual says to seat them then backout the specified number of turns. Seated to me means firm. Should I put the pilot screws in thill they stop?<br />Again much thanks for your time!