2006 Yamaha 2 stroke revs up in idle.

[Chaser3]

Only happens occasionally and not necessarily when it is cold. Makes docking difficult when shifting into gear. It will then idle back down by itself. Frustrating. Thoughts?
Chaser3

 

[Grub54891]

Re: 2006 Yamaha 2 stroke revs up in idle.

Air leak,or dirty carb?

 

[Capt Ken]

Re: 2006 Yamaha 2 stroke revs up in idle.

How about more info like model number?

 

[Bamaman1]

Re: 2006 Yamaha 2 stroke revs up in idle.

I would start by having the carb. pulled, disassembled and cleaned. Chances are your problem will be solved. Just a can of carb. cleaner is needed--no carb. kits are required.

The engines using 90/10 gasoline really need carbs. cleaned from time to time, as it's causing so many running problems.

 

[99yam40]

Re: 2006 Yamaha 2 stroke revs up in idle.

06 50 hp 2 stroke will be a prime start model. It would be a good idea to post model # in main part of thread, putting it is a 50hp motor where you did may not show up very well.
Timing is advanced when cold starting along with the additional enrichment.

So the timing could be affected if the temperature switch that tells CDI motor has warmed up is not making a good connection.
Might monitor timing to if it is advancing above idle spec when idle RPM increases.

Might check to make sure stat is functioning properly also if the timing is moving, could be motor gets too cold due to stat sticking open

 

[cgman72]

Re: 2006 Yamaha 2 stroke revs up in idle.

i have a 96' 2 stroke merc, 30hp oil injected, practically a new motor (hardly used), same problem. runs perfectly smooth warming up, kicks butt across the lake, etc... its only when I come out of gear/ high speeds and into neutral, it'll idle down as it should, then it revs up about 1000 rpm for 5-20 seconds and returns to smooth idle... weird. dismantled the carb tonight, everything looks REALLY clean, will spray down and put new gaskets tomorrow, etc... if that doesn't do the trick, will continue the process of elimination. stay tuned...

Update: cleaned the carb & fuel filter. was hardly dirty at all, the guts were practically new inside. reassembled. everything seems to run very good in the yard. will put on water tomorrow for load test. stay tuned...