Logo
FULL SITE MENU

Bad Gimbel bearing?

R

rickt

Member
We moved this spring/summer....just getting around to using the boat.........Can anyone help diagnose a noise that just started....I have a alpha 1 V8. Last night I started to hear a loud rattle in the engine compartment. It sound almost like I had a diesel instead of a gasoline engine. I pulled the cowling up...the engine sounded fine the noise was lower....I assume in the out drive. Does this sound like a Gimbel bearing....How can I tell for sure?

The noise was present sitting at idle (in nuetral) as well as in gear. Last year I felt some vibration.....thaought it was the U joints figured I would change them this summer...then we moved.....everyone was ready to get out so we did......

Thanks in advance....

Rick
 
gimble bearings usually growl, u joints rattle, especially if they have lost the bearings in the cap and you now have some play in the cross. time to pull the drive and take a good look, you can check the gimble then. you didnt say what year or the last time all your rubber was replaced, maybe do it all in one swoop
 
Roscoelab

Thanks for the reply, I am past do for a tear down inspection. I will keep you posted on what I find and get your advice.


I am reasonably mechanically inclided....I used to race motorcycles....do all of my own car repairs ect....but this out drive stuff is new territory.


The boat is a 1986 Four Winns. I have had it for about 6 years. Because of general busyness, work, graduations ect....I do not get out as much as I would like. I have not changed the u joints or gimbel yet....I don't have any idea when they may have been changed.


Thanks for the feedback I appreciate it.


Rick
 
Ujoints typically last a long time. They are the least replaced item unless not serviced properly or exposed to water but can fail, just not as often.

The gimbal bearing is a more common failure item and is more suspetable to the same causes, water and or lack of proper maintanence.
 
I would suspect you can.

But I ALWAYS reccommend OEM for components for repair and or replacement that take a lot of abuse or are critical.

It is your boat but if I was to do the repair I would buy from mercury dealer or online retailer selling qualified replacement parts.

This web site that hosts this forum sells parts............
 
Kghost

Maintenance? What mantience does the gimbel require? I am not trying to be stupid.......I know it may sound like it.........Also as part of winterizing do I need to pull the outdrive and grease the u joints....assumeing they have zerk fittings. I hope to pull it apart this evening. It may rain.....
 
Not sure which way you will end up going, but I have a list of auto part numbers I have accumulated from different forums online. Also not sure if which these are for Bravo or Alpha or if they are different, but maybe someone with more knowledge can help etc.

U-Joints
SPICER# 5-1306X
PRECISION (MOOG)# 315G
TRW (FEDERAL MOGUL)# 20030 / 20030P
 
Well......I got it pulled apart....thr u joint seem good very tight with zerks, clean no rust. Maybe it is the Gimbel.....I may be in over my head at this point....Any Idea what a boat mechanic would charge for this type of repair?
 
A few thoughts:

1- if it is the gimbal bearing, it's not that hard to replace. You can do it with the drive off, through the drive bell housing and boot. But inspect it first! Does the inside race turn smoothly? Any clicking or roughness is cause for rejection. Is there very little fore to aft end play? If you feel the need to replace it, you can get the old one out by using a slide hammer puller (available at Autozone through thier tool loaner program). There is a special tool to install the new one, but if you tap it slowly using a block of hard wood, making contact with the outer race only, it'll be fine. Just make sure the grease holes are lined up to the grease port on the outer transom housing.

2- don't discount the engine coupler as the source of your noise. That would require pulling the engine to replace. It bolts to the flywheel and to access it you have to remove the bell housing, which is also the rear engine mounts.

3- since you have the drive off, get an alignment tool and check the alignment. This is likely the smoking gun that started the problem.

4- a very remote possibility would be the bevel gears and/or bearings in the upper unit. You can take the top cover plate off and take a look. Just be careful, the top cover plate is also the bearing housing for the vertical shaft.

No idea what it would cost you to take it to a shop, but stand by for heavy seas!
 
Last edited:
Just a thought, if its kind of a clanking noise, could be an exhaust shutter. I'm not sure how easy it is to check on your boat, but my 93 mercruiser 4.3 is easy to get at.
 
Gimbals? does it roar continuously when engine started even out of gear? probably yes. If you have pulled the lower unit, reach up inside find hole stick 2 fingers in hole (sounds nasty) turn back and forth smooth no play good bearing (change anyway) crunchy and stiff (now u know what a bad gimball is).
 
Back
Top