Yamaha 15-hp outboard stalls at idle?

zhengpeng

Recruit
Joined
Oct 13, 2011
Messages
2
Hi,

I have a Yamaha 15-hp 2-stroke outboard. Last Sunday it started stalling at idle speeds. It had no problem if put in gears (this model only has Forward/Neutral/Reverse) and throttled up. What could be the problem?

What I did was pulling out the choke knob and giving the starter handle a full pull. It worked well to this point. And then I pushed in the choke knob and the it stalled a few seconds later.

An interesting thing I observed was: if I pulled out and pushed in the choke knob frequently when the outboard is at idle speeds, it did not stall (or took much longer time to stall).

I shifted it in Forward and ran it for about 30 minutes (with the choke knob fully in its home position). No problems. But when I put in back to Neutral, it still stalled.

Is it because of the temperature? I am located in the New England area and the temperature is around 50-60 degrees during the day.
 

zhengpeng

Recruit
Joined
Oct 13, 2011
Messages
2
Re: Yamaha 15-hp outboard stalls at idle?

BTW, last Friday, some friends used the outboard and they used 1:25 oil/gas ratio. Could this be a problem?

I later used a fresh tank of gas with 1:100 ratio but still had the idle stalling problem.

Any ideas?
 

pscrabber59

Petty Officer 1st Class
Joined
Apr 12, 2010
Messages
246
Re: Yamaha 15-hp outboard stalls at idle?

idle stalling problem may be a carb related issue. Have you fooled with the carb idle settings recently?? On the other hand that mdl. motor runs usually on a 100:1 mix so when your friends ran 25:1 it might have fouled the plugs, check them and if fouled replace them. I just bought a 1995 Yami 6hp two-stroke and owners manual states run 100:1 gas-mix.
I was going to run 50:1 on this motor but i tink i will stay with the 100:1 mix so i wont have any problems. The orig. owner said he always used 100:1 mix.

Gd. luck
 
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