1989 Cobra on 4.3 liter engine makes a funny noise

[rolmops]

While testing my engine I heard a funny noise coming like something rattling from in or around the outer unit. It sounds like a loose piece of metal banging against something. It is not bothering the engine or lower unit performance (as yet) and when I engage the gear it goes away. For now I will dig up my stethoscope and see If I can more precisely locate the source of this noise What could it be and what should I pull apart?

 

[Mc Tool]

Ooooh ! that sounds expensive . I would start looking at either the motor or the drive unit .

 

[rolmops]

I used the stethoscope to pinpoint where the noise is from and it is neither in the engine , nor in the lower unit or gear housing. So far , that is good news.
I'm hoping , maybe a loose screw or something that fell down when attaching the lower unit. The funny thing is that the noise is gone .

 

[Chris1956]

When I had my sterndrive in salt water, every spring there was small pieces of rusty steel in the bilge. Lots of non-critical items would succumb to rust. You might look around for some of that. Also, the cover over the ring gear, next to and down from, the starter can rust and rattle.

 

[rolmops]

I didn't consider that. thanks for the heads up

 

[Bondo]

While testing my engine I heard a funny noise coming like something rattling from in or around the outer unit. It sounds like a loose piece of metal banging against something. It is not bothering the engine or lower unit performance (as yet) and when I engage the gear it goes away. For now I will dig up my stethoscope and see If I can more precisely locate the source of this noise What could it be and what should I pull apart?

Ayuh,...... Did yer motor have exhaust shutters,..??
If so, I've found that burnt up shutters in ole Mercs can fall down into the y-pipe, 'n rattle,.....

 

[rolmops]

Come to think of it, I did replace the exhaust shutters. Although I don't think that I dropped anything down there but there is a fair chance that something fell down.
Anyway this sort of problem is very small change compared to the engine falling apart.

 

[rolmops]

So I found out why there was this nasty noise. Last year I had problems with the gimbal bearing slipping out of place. So I took it to a well known mechanic shop on Eastern Lake Ontario where they managed to put it in place. Upon taking off the lower unit I turned it by hand and it became clear this gimbal bearing was shot. I saw that they had put the gimbal in backwards, and, although they had told me that the one they put in was a non greaser bearing, It turned out to be one that needed to be greased. I had a very hard time getting it out. mostly because they had slammed it in not only backward, but also under an angle instead of straight. When I finally got it out with the help of a lot of unprintable words, I replaced it and now all the nasty noises are gone. The problem was a simple one and a cheap one, so I figure I got lucky.

 

[kenny nunez]

If water gets in the bellows all the grease gets washed out. The bellows must always remain dry to protect the bearing.
The fact that the bearing was not seated will defenitely make noise as it causes the joints to be over loaded and putting too much linear pressure on the input shaft bearings. I must say sometimes it is impossible to get the bearing squared up if the tolerance ring does not stay in place when the bearing is being installed.
Glad you finally got the noise fixed. Good job.