yamaha 40 hp wont idle NEED HELP PLEASE

rcurran

Recruit
Joined
Aug 22, 2011
Messages
3
i have a yamaha 3 cylinder 40 hp outboard that wont idle. one day in ran fine the next day it wont idle. i cleaned the carb changed the spark plugs and clean the fuel system. does anyone know what could cause this ??
 

ChrisMA

Seaman
Joined
Jul 6, 2006
Messages
67
Re: yamaha 40 hp wont idle NEED HELP PLEASE

Do you have a shop manual? Poor idle could be caused by a multitude of issues including the carbs low-speed being too lean or too rich or the timing could be off. What do you mean it doesn't idle? You start it and it immediately dies or will it idle for a while then die? Does it run at high throttle speeds? Does it run on muffs?

Chris
 

rcurran

Recruit
Joined
Aug 22, 2011
Messages
3
Re: yamaha 40 hp wont idle NEED HELP PLEASE

Hi Chris
It will run at high idle 3000 rmp or higher but it won't run below 3000 rpm or idle. Pump the gas a few times it may idle 15 secs at most then die. Right now it is running at high idle on muffs. Basically one day it was running fine the next day it won't dle.
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,851
Re: yamaha 40 hp wont idle NEED HELP PLEASE

Check the fuel pressure/vacuum and inspect the pump for leaking into crankcase,
Check timing.
what is the motor model # ?
Is it a prime start or choke?
 

rcurran

Recruit
Joined
Aug 22, 2011
Messages
3
Re: yamaha 40 hp wont idle NEED HELP PLEASE

Model number f40ltrz. You can prime start but it does have a electric choke by pushing the key in.
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,851
Re: yamaha 40 hp wont idle NEED HELP PLEASE

This may be a 4 stroke motor 2001 if the model # is F40TLRZ not f40ltrz
There is a big difference between the prime start models and the ones with electric choke and the TLRZ has prime start according to the parts look up.
I would have to say you need to clean the carbs properly and then have them adjusted properly and that will require a service manual and the proper equipment(Multi channel Manometer) from what I have read on the 4 strokes
 
Top