40 hp yamaha won't idle

UA72

Cadet
Joined
Feb 23, 2003
Messages
8
I have a 40 hp yamaha outboard that won't idle or run good at slow speeds when in idle it runs about 15 seconds then shuts off at low speeds it sounds like it wants to bog but if you give it full throtle it will take off and run fine, back about a month ago I got some water in the gas at a country store once I narrowed it down I drained the tank .fuel lines and carb. I put good gas in it and unplugged the gas line and ran it till it ran out of gas but I stll have this problem can anybody help me thanks
 

99yam40

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Joined
Sep 7, 2008
Messages
8,851
Re: 40 hp yamaha won't idle

I have a 40 hp yamaha outboard that won't idle or run good at slow speeds when in idle it runs about 15 seconds then shuts off at low speeds it sounds like it wants to bog but if you give it full throtle it will take off and run fine, back about a month ago I got some water in the gas at a country store once I narrowed it down I drained the tank .fuel lines and carb. I put good gas in it and unplugged the gas line and ran it till it ran out of gas but I stll have this problem can anybody help me thanks


pull and clean the carbs
 

UA72

Cadet
Joined
Feb 23, 2003
Messages
8
Re: 40 hp yamaha won't idle

Is pulling the carbs the only way to get the water out can't something be added to the fuel
 

99yam40

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Sep 7, 2008
Messages
8,851
Re: 40 hp yamaha won't idle

pull and clean or end up chasing this problem for a while and even end up with more problems
 

AndrePSP

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Joined
Apr 24, 2010
Messages
27
Re: 40 hp yamaha won't idle

dont know if you got it fixed. but my 40 horse had similar issues. I rebuilt carbs ne,w gas tank/filter, and what ever. turned out it was my switch box.
 

mdawson28

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Joined
May 18, 2011
Messages
13
Re: 40 hp yamaha won't idle

dont know if you got it fixed. but my 40 horse had similar issues. I rebuilt carbs ne,w gas tank/filter, and what ever. turned out it was my switch box.

what is a switch box?
do you mean a cdi unit on the side of the motor?
 
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