Yammaha 115 two-stroke start/idle problem

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I'm new here, so I apologize if this is a tired question. I searched this forum pretty thoroughly, but I couldn't find a thread that addressed my exact issues, so maybe someone out there can help me out.

I have a 1996 Yamaha 115 two stroke that runs like a top, EXCEPT....

At idle, or at very low rpm when in gear, the engine frequently cuts out. There is a little "sneeze" from the engine when this happens. Also, the engine usually needs to be fully choked to start, even when it's warm. Is this just a carb adjustment problem? Running a little lean, maybe? I'm reluctant to mess around with it without some sound advice. Thanks

 

[JUSTINTIME]

Re: Yammaha 115 two-stroke start/idle problem

time to rebuild the carbs and get a sync and link

 

[spinner]

Re: Yammaha 115 two-stroke start/idle problem

time to rebuild the carbs and get a sync and link

This engine only has 152 hours on the clock, and the previous owner, whom I know personally, always took extremely good care of it (stored inside winters, tune-up every spring, etc.), despite the fact that he hardly ever used it. The boat sat in storage all of last year, so the carbs might be a little gummy due to the long period of inactivity, but should a rebuild be required after so few engine hours?

 

[Ray Neudecker]

Re: Yammaha 115 two-stroke start/idle problem

The rebuild has more to do with the condition of the carbs rather than age.

 

[wvstriper]

Re: Yammaha 115 two-stroke start/idle problem

I agree with others that you may need some carb work. However, I have a few questions for you. How old is the gas in the tank, and do you pre mix your gas ( c115 motor)? I have a '97 c115 and never had a problem with it until this spring. I decarbed the motor this spring (before I had run the boat normally) and started having similar problems as yours. I thought the decarbing screwed things up, but after running through last years gas (which was treated with stabil in November), adding a Yamaha mini micron-10 filter, and adding a fuel treatment (Startron) it is back to running just fine. What was actually wrong? I really don't know. The fuel I added in the fall was 10% ethenol. It may have 'cleaned' my 10 year old tank of some crud (I premix). Maybe the decarbing plugged up something in the carb (jets, ect.). Maybe I just had a bad batch of gas. It could be combinations of multiple things. I'll never know for sure, but after investing $40 in a filter assembly (which I wanted anyway), $10 for fuel treatment, and a tank of fresh fuel I'm back in business. I just followed the KISS principle! After 20 hours I plan on replacing the filter and cutting open the old one to look for crud. Hope this helps.

 

[Ray Neudecker]

Re: Yammaha 115 two-stroke start/idle problem

The most common problem with carb motors which have set up. Clean fuel is the life blood of the engine. That filter will save many headaches. lot easier to change it than build carbs.