1993 40 yamaha idle problems

bassstrat

Cadet
Joined
Dec 1, 2008
Messages
13
My 93 40 yamaha outboard is having problems idling. It will chirp/sneeze over and over and if I don`t throttle it up,it sometimes shuts off especially when I put it into gear. I`ve adjusted the idle screw next to the carbs and have cleaned the carb jets and it does`nt seem to do much good. If I run the motor and then recrank it within a few minutes,it does`nt give me much of a problem,otherwise it`s very hard to get going and keep running at lower speeds.Once up to speed it runs like a charm.Any suggestions? Thanks, Bassstrat...P.S. I forgot to mention that the motor had 70 carbs on it when I bought it,but it now has the 40 carbs.It also has a 50 exhaust tube on it at this time.....
 
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biggs

Recruit
Joined
Aug 16, 2009
Messages
2
Re: 1993 40 yamaha idle problems

My 93 40 yamaha outboard is having problems idling. It will chirp/sneeze over and over and if I don`t throttle it up,it sometimes shuts off especially when I put it into gear. I`ve adjusted the idle screw next to the carbs and have cleaned the carb jets and it does`nt seem to do much good. If I run the motor and then recrank it within a few minutes,it does`nt give me much of a problem,otherwise it`s very hard to get going and keep running at lower speeds.Once up to speed it runs like a charm.Any suggestions? Thanks, Bassstrat...P.S. I forgot to mention that the motor had 70 carbs on it when I bought it,but it now has the 40 carbs.It also has a 50 exhaust tube on it at this time.....

any resolve to your problem( i'm having that same issue)? i don't want to rebuild the carbs ,but i think it just may be the problem. i've already troubleshot the easy solutions
 

Doh

Petty Officer 2nd Class
Joined
Aug 12, 2008
Messages
193
Re: 1993 40 yamaha idle problems

I would adjust the Idle Air Screws. A Slotted screw jet on the top left side of the carbs, close to the engine.

Now these are Air Screws,so they are oppisite to jets, turning them in will enrichen the mixture. They run from 0-1/4 throttle. Give them about 1/4-1/2 turn in.
 

bassstrat

Cadet
Joined
Dec 1, 2008
Messages
13
Re: 1993 40 yamaha idle problems

Will this give the carbs more fuel? It seems that if I don`t choke the engine after a 5-10 minute period(while fishing or whatever) the motor won`t start. It seems to be starving for fuel????Thanks,Bassstrat
 

BEH

Cadet
Joined
Jul 27, 2010
Messages
10
Re: 1993 40 yamaha idle problems

I have the 30 hp 3 cylinder. Each screw has a different factory setting . Are you suggesting turning in all 3 screws, the same amount???
 
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