Vibration

[miluemta]

Hi all,

I have a 12' aluminum boat with a 5hp mercury. I ran it for the first time the other day and the boat and motor vibrates something fierce. The top speed is about 5 mph. I ran the same motor on a 12' polyethylene boat and it went about 15mph with no vibration at all.

Is there a way to dampen the vibration or is there something wrong with the engine? It seems like I'm losing power to the vibration. I also noticed some small nicks on the prop, that wouldn't throw off the balance that much would it?

If I get a new prop and want higher top speed, what pitch should I move to? It currently runs a 8 3/8" x 7 pitch, 3BL RH aluminum.

Any help is greatly appreiated, thanks.

 

[miluemta]

Re: Vibration

This engine had sat in the garage for several (probably about 5 or 6) years but, was bought brand new and had only been ran twice before storing it in the garage.

We got it out, opened it up and it was still looking clean and new under the hood. We cleaned out the gas tank and fuel line, added 2-cycle mix and it started right up. It seem to run fine on the first boat then not on the second boat.

Could the spark plug be bad from sitting even though it hasn’t been used much? Is there anything else that might need maintenance (oil or greased)?

Thanks