91 Yamaha 8hp won't idle

I

iainthardtofind

Cadet
Joined
Jun 30, 2003
Messages
9
I bought this motor from a guy who ran (started 1st pull) it on a flusher for me. It idled great but the impeller was bad so there was not much water output. His fuel mixture was the factory rec, 100:1. I replaced the impeller and surrounding gaskets.<br /><br />Using my own tank I get gas and end up with roughly a 62:1 gas/oil ratio.<br /><br />(Running in tub)<br /><br />I fire(Started first pull) the engine up after the impeller replacement but now the engine dies after a few seconds. To keep the engine running at idle I must crank it to high idle. If I try to engage in gear there are not enough RPMs and it stalls.<br /><br />The only way I can get it in gear is to pull the choke a little to raise the RPMS, then change. Once in gear it runs fine, until low rpms, then it will stall.<br /><br />I replaced the plugs and tried again but I'm still having the same problem.<br /><br />I also decided to change the gas/back to 100:1, so I did the math and added gas.<br /><br />SAME PROBLEM, Motor will not idle
 
T

trumpetbucks

Petty Officer 2nd Class
Joined
Jun 2, 2003
Messages
140
Re: 91 Yamaha 8hp won't idle

Have you tried adjusting the idle mixture?<br /><br />If you have a manual, this is an easy procedure to follow.
 
H

Harry Usher

Recruit
Joined
Jun 29, 2003
Messages
3
Re: 91 Yamaha 8hp won't idle

Mine always smokes when idling, but not when running - I always think a bit of smoke at idle is a good thing as it means you have oil in the mix, and are therefore lubricating the engine. You might have dirt in the carburetor - either drain via small screw on bottom, or take off and clean out which takes about in all about 10 minutes
 
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