Pontoon vibes in Harris 24'

[destes]

I have a 93 24ft Harris Floatbote with 3.0 L/LX Mercruiser
Vibes initiated when hitting waves or boat wake. Can be stopped by reducing throttle. Been to shop several times with no solutions. Is there a harmonic between the boat and engine drive or prop being activated when the toons impact the waves?

 

[ahicks]

I have a 93 24ft Harris Floatbote with 3.0 L/LX Mercruiser
Vibes initiated when hitting waves or boat wake. Can be stopped by reducing throttle. Been to shop several times with no solutions. Is there a harmonic between the boat and engine drive or prop being activated when the toons impact the waves?

I worked at a dealer selling new Harris boats in the late 80's, and I can tell you there was a very noticeable difference in the vibration between the OMC and Merc I/O's from the time they were new. The OMC was a lot smoother and quieter. Point being your complaint is no surprise here.

I would check the prop shaft and prop, than give the engine a good going over to make sure some goof ball didn't bypass the vibation isolation (motor mounts) somehow. If that all checks out, it is what it is.....

 

[destes]

I worked at a dealer selling new Harris boats in the late 80's, and I can tell you there was a very noticeable difference in the vibration between the OMC and Merc I/O's from the time they were new. The OMC was a lot smoother and quieter. Point being your complaint is no surprise here.

I would check the prop shaft and prop, than give the engine a good going over to make sure some goof ball didn't bypass the vibation isolation (motor mounts) somehow. If that all checks out, it is what it is.....

Thank you. Great feedback. Just completed several engine items, runs great. The shops did confirm motor mounts were good. Prop replaced last year with a Solace 3 blade, same specs as old one. Do you think a 4 blade might make a difference? I will check the shaft just in case. This vibe has been around for several years. Never felt like it was going to come apart but embarrassing with passengers. Being an x helo pilot I really dislike vibrations.

 

[ahicks]

I can't relate to full scale helis, but the RC heli's can be pretty sensitive as well.

You may be able to kill some of the vibration noise a little here and there. The alum. skin for example, where it's riding in a channel big enough to allow it to rattle, can be pretty easily silenced to reduce/eliminate that noise source.

 

[destes]

Thank you. Great feedback. Just completed several engine items, runs great. The shops did confirm motor mounts were good. Prop replaced last year with a Solace 3 blade, same specs as old one. Do you think a 4 blade might make a difference? I will check the shaft just in case. This vibe has been around for several years. Never felt like it was going to come apart but embarrassing with passengers. Being an x helo pilot I really dislike vibrations.

 

[destes]

Got a few of those noises also. Guess we all start rattling and making odd noises as we get older. Thanks again Capt.

 

[oldboat1]

It sounds like the 3.0 is struggling at the top of its range. Perhaps it is running too rich.