sneeze and stall on 9.9 yamaha

[danberlin]

My 1998 9.9 two stroke yamaha is sneezing and stalling at idle.I have cleaned the carb twice using carb cleaner and compressed air.I also changed the fuel filter ,primerbulb and gas line,and switched tanks emptying the spare one out and refilling with fresh fuel.Still sneezing .It runs good above idle.There was some black crap in the old filter.Thats why I changed all the other stuff after the first carb cleaning.
I don't know if it matters but it wasn't coming up to temp while I messed with it ,the head was cold after idling for a while (it will idle with the choke).So I probably need a thermostat but will that cause these symptoms?
Thanks for any input
Dan

 

[yanker]

Re: sneeze and stall on 9.9 yamaha

Dan,
I have similar problem with my motor. When I was washing it down, it made squeak noise then stopped. When I was talking to local boat mechanic, he said it is caused by thermostat not closing and does not let the motor get warm. He called this "lean sneeze". It also causes motor to run lean. He said thermostat is only really used when idle. All rest of time it is wide open. I've ordered thermostat and gasket for my motor and just waiting for UPS to deliver it this week. I hope this helps.
Ron

 

[danberlin]

Re: sneeze and stall on 9.9 yamaha

Ron
Thanks for the reply.Thats good news actually because I was about to tear my carb apart for the third time.Where did you order your thermostat from?My local dealer quoted me $31 which seemed steep.
Thanks
Dan

 

[yanker]

Re: sneeze and stall on 9.9 yamaha

Dan,
I guess thermostat cost must be in that range, because mine is costing me $33.85 from Browns Point. They are located in NJ and they handles suzuki parts. After driving around and going to various local boat repair places, they don't really stock the parts. They said that they can order parts for me, but would seems easier ordering it myself. I'm hoping this thermostat gonna fix my problem, so can go out fishing again.
Ron

 

[danberlin]

Re: sneeze and stall on 9.9 yamaha

Ron
You made my day! New thermostat did the trick.The motor idles great. Hope it works for you as well.
Thanks
Dan