yamaha 200hp two stroke vibration problem

[swan20]

Good day all,

I bought a used 1995, 200hp two stroke Yamaha couple of month ago, the engine runs great, however at low rpm and speed (probably less than10miles/h) I?m noticing high vibration but when I speed it up it runs smoothly. I took it to a Yamaha dealer for a checkup and they said nothing was wrong with it, the pressure is fine and sparkplugs are ok. Is this normal or not?

Appreciate it...

 

[robert graham]

Re: yamaha 200hp two stroke vibration problem

I believe that motor has a balancer device on it that can malfunction, or you could be loosing spark to one or more cylinders due to electrical problem. I would take the boat out on the lake and run it until it starts the vibration, stop and pull the spark plugs to get a reading on possible problem. The plugs can tell you a lot about certain problems. Good Luck!

 

[drakocy]

Re: yamaha 200hp two stroke vibration problem

i have the same issue, my mechanic friend has told me, my engine 200 ethl, is a high compression engine this was built for performance,, meaning high test gas and higher rpms then idleing, some may disagree, it does not idle well at all, i have a kicker motor, and a minn kota 24 troller with auto pilot, and copilot,
good luck

 

[99yam40]

Re: yamaha 200hp two stroke vibration problem

Your owners manual will tell you what octane fuel it is designed to use.
I think I remember something I read about some motors dropping out some cylinders at low idle but I have no idea if yours is one of them. What RPM is this happening and what RPM does it seem to go away?