Vibration/Rattling - HELP

[mmcguire2002]

I took my boat out on Saturday and noticed she has a severe vibration and rattling when running on the open water. I have not hit anything or fouled the prop. When I pull the throttle back to 7 knots or less it runs normal. The minute I push the throttles to get on plane and cruise, this noticable rattling and vibration happens. Any ideas what this could be...?:huh:

 

[skolbe]

When - I had a prop that hit a log - that was the exact same scenario - I experienced.

 

[mmcguire2002]

WHat had to be done to fix it and how costly was it? Thanks.

 

[sbw1]

When is the last time you inspected your running gear? Are you in salt water?

 

[mmcguire2002]

I am in salt water. A diver goes down on my boat every 3 weeks to clean it, so if there was something obvious, he would spot it.

 

[skolbe]

I had to pull the boat and have the prop redone. The haulout was more than having the prop redone. I ended up having both props rebalanced. It was the smoothest the boat ever ran. It was under $1k - haulout was a big part of my bill.

 

[mmcguire2002]

I assume you had to haul it before you confirm this was the issue? How long did the process take?

 

[sbw1]

Before you pull it, have look the alignment and the shafts where they go through the hull. Are you getting leaks? Is everything connected with no missing bolts? If nothing looks amiss you'll just have to haul and look at cutlass bearings, props, shafts and go from there. I had my boat hauled a couple of years ago because of the same symtoms you describe. When out of the water we pulled a piece of landscaping plastic off the shaft. I had been anchored in a small shallow lake and while pulling up the anchor, we some how picked up the plastic and it go wrapped around a shaft. Cost about $90 to pull the boat out of the water and it was back in the water in five minutes after removing the debris.

 

[mmcguire2002]

Wow...$90 to pull the boat is fantastic. It will cost me $500+ here. I think if there was something wrapped up on it, my diver would see it. I'll check the shafts and bolts as you suggest. Thanks for the input.

 

[osd9]

Has your diver been under the boat since you noticed the vibration? You could have picked up a bag or a small line just idling out of your slip.

 

[mmcguire2002]

Good question...the diver has not been down since this weekend.

 

[Hampton]

Check to make sure your tabs are working - still attached firmly and cycling up and down correctly. I had a buddy lose the bolts connecting the tab to the cylinder. His symptoms were the same. We used a line to tie the tab up while on a trip in the ICW. No more vibration. He has a 420 with diesels. The tab flapped with the movement of the prop at higher RPMs until we tied it up.

 

[mmcguire2002]

Interesting....hadn't thought to check the trim tabs. I'll look at them tomorrow and make sure they are in working order.