yamaha 115hp 2 stroke spring surprise

[bayrat]

9th season with my engine. First problem. Started her up yesterday and she started and idled fine. As I increase RPM above the 2000 rpm range she misses. I changed plugs, water seperator filter, and have fresh fuel and yamalube in the tanks. I cant tell yet if it's one cylander missing every time or if it's random. I rely on steady maintenance since i'm not much of a mechanic to keep things running. This problem
has me stumped. Any suggestions or advice? Thanks in advance for any comments or help. Jeff

 

[bayrat]

Just a maintenance amt of ring free, not an overly strong concentration. I'll try the carb cleaner, and hopefully that will clear it up. I'll let you know if that does the trick. Thanks.

 

[POGE]

another vote for carb issue.
If the cleaner does not solve the issue, might be a bad float in the carb issue.

 

[bayrat]

How about this for an answer. It's normal for the engine to miss when in neutral and above 2000 rpm for a few minutes, due to a lack of a load on the engine. I'm not a mechanic but engine timing is apparently different when in neutral as opposed to under a load (in gear). I will test her on the water within a week or two and see if this is the case. I hope the mechanic is correct!

 

[striperon1]

I have this problem. The shop tech and I worked for more than an hour diagnosing the problem. Turns out one of the carbs needs to be rebuilt ('98 130 Yamaha V-4). Have to order parts and fix it next week.

We got it running (poorly) without the motor cover and carb cover. Then we hand choked it and worked the throttle. On one carb the engine would slow from flooding. On the other carb, nothing happened. Those two cylinders were starving for gas.

The high speed jets were plugged and the bowl had a brown mixture in it from water, gas and oil mixing. The engine was winterized by the marina, and a new separator filter was installed before winterizing.

 

[bayrat]

Good luck! My engine runs fine in the water, so I'm feeling relived. I hope your problems are resolved soon. At least you know your problem and your solution. Not knowing those two things can make for a frustrating time!