Vibration from Merc 260

[jpopp]

Have 23' Chris Craft with Merc 260. All of a sudden had problem with noise/vibration heard down in cabin. Took it out and couldn't plane or get above 3000 rpm. Two days later changed cap, rotor, plugs and might have found that a wire was off. Took it out and was able to plane and drive fine but noise is still there. Wondering if something could be loose (motor mount?), kind of new to engines and boats but learning a lot as I go. Do have new fuel filter/water separator that I am going to install but can't explain what might be causing vibration.

 

[McKenzie]

Re: Vibration from Merc 260

Is the prop damaged at all? Is it on tight? A prop once came loose on me and drove me crazy trying to figure out the problem.

 

[greasemonkeyozi]

Re: Vibration from Merc 260

Yes this guys right, check to see if your prop wobbles. If so, check your sheering mech. Normally if the whole boat vibrates, its gonna be the prop.

 

[jpopp]

Re: Vibration from Merc 260

I should have added to my original post that vibration and noise is really only noticable when engine is idling in neutral, so I figured the prop wasn't the problem since it is not rotating when I am hearing the noise

 

[McKenzie]

Re: Vibration from Merc 260

Does the engine shake a lot at idle? What year is the engine/boat?

 

[jpopp]

Re: Vibration from Merc 260

The boat and the engine are a 1985 and yes it shakes/vibrates at idle. Don't notice it much once underway.

 

[flashback]

Re: Vibration from Merc 260

jpopp, do a compression check, sounds like you may have a cylinder not fireing.... also pull the plug wires one at a time and listen to the engine. pull a wire, listen, if engine runs roughly then that cylinder is working, if not, then replace spark plug and try it again. only pull one wire at a time if it makes a difference in the sound then that one is ok. go on to the next until you hit the one that does not make a difference, that one is the problem........