Yamaha F100 - poor starting and rough idle.

Racerteb

Recruit
Joined
Jun 4, 2003
Messages
1
At the end of last summer the motor began to idle very rough and often stall at slow speeds - ran fine at higher revs. This spring I had plugs and fuel filter changed. First time I tried to start the motor, it refused. After spraying starting fluid into the intake area it started immediately. Then after approx 20 seconds it would run rough again until I sprayed more starting fluid - then would would run parfect. After getting it into gear and throttling up, it runs fine - when I back down on the throttle it quits. Any ideas?<br /><br />Engine is four stroke - 1999 w/about 200 Hrs.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Yamaha F100 - poor starting and rough idle.

She is not getting enough gas at start or idle.<br /><br />What happens if you pump the primer bulb? You may have a weak fuel pump or fouled idle circuits in the carbs, but it is more likely just out of tune.<br /><br />Start with a Service Manual. Set up the carbs and idle speed according to the book.<br /><br />Good luck. :)
 

Yamafan

Cadet
Joined
Oct 20, 2000
Messages
16
Re: Yamaha F100 - poor starting and rough idle.

Where does one buy this service manual. I have a problem with a stumble at 21-2900 RPM otherwise fine.
 
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