Noise From Rear of engine At Outdrive.

M

Michaelbluewolf

New Member
Apr 4, 2011
35
Lumberton, NC
Boat Info
1970 Sea Ray SRV 190 I-6 250 CID I/O
Engines
Mercruiser 165
Hello To All,
I have recently replaced the engine in my 1970 Sea Ray SRV 190 with Mercrusier 165 inline 6 With pre Alpha outdirve. Since I have never ran the boat [project boat had blown engine], I am not familar with normal or abnormal noises. The engine runs fine has 20 PSI oil pressure at idle and runs 160 Degrees on earmuffs in the yard.
Note all the engine covers and rear covers are out of the boat. The noise is in the area at the rear where the engine coupler is and is quite loud rotational sound. The gimbel bearing looked new and P/o Owner claimed it was new. The engine coupler came with the used Mercusier engine looked fine, no cracks in the rubber.
I lubed every thing with red grease, outdrive ujoints, All zerk fittings on the outdrive. I may be overreacting to the noise. I was wondering if someone else could share thier experience in the matter.
Thanks Again for your Help, Mike
 
could you make a video of the noise? Hearing it would make identifying the source much easier.
 
Hello 270win,
I don't have a good video camera. I only have a small camera with built in sound thats not very good.
I am thinking of taking the boat to my local Marine Mistro here in town and see what he thinks. He has many decades of experience and I agree after 30 plus years as a Automotive Tech noises are something you have to hear to diagnose.
I do appreciate your response and Thank you helping me make a decission concerning this noise. I am a little OCD since I installed the engine and had a problem getting the outdrive to slide back into the engine coupler and gimbel bearing. Finally after many adjustment to the engine mounts, the outdrive slide home.
Thanks Again for the response.
Mike
 
I would guess an engine alignment issue where the coupler isn't pefectly aligned if the sound seems rotational
 
Michaelbluewolf said:
Hello 270win,
I don't have a good video camera. I only have a small camera with built in sound thats not very good.
I am thinking of taking the boat to my local Marine Mistro here in town and see what he thinks. He has many decades of experience and I agree after 30 plus years as a Automotive Tech noises are something you have to hear to diagnose.
I do appreciate your response and Thank you helping me make a decission concerning this noise. I am a little OCD since I installed the engine and had a problem getting the outdrive to slide back into the engine coupler and gimbel bearing. Finally after many adjustment to the engine mounts, the outdrive slide home.
Thanks Again for the response.
Mike
Click to expand...
Hey Mike,
Did you use an alignment tool when you installed the drive?

is the sound rhythmic like a bad U joint might make on a car? Or is it constant like a dry bearing sound?
 
Hello Again,
I used a spare drive shaft end that I got from the guy I bought the Mercrusier engine from. I adjusted the rear and front engine mount till the shaft seemed equally centered in the gimble bearing and then installed the outdrive. I used a lot of grease on the input shaft on the outdrive, I stuggled with this for quite awhile, untill the O/D finally slipped in enough and then tightened the 6 retaining nuts and torqued them down.
Does this sound like this could be the problem. Could the O/D C/V shaft be causing this noise and if so what would be the next move.
Thanks to 270win and moparlvr4406
P.S. The noise is a consant rotational sound, More like a drive shaft support bearing that going bad.
 
Last edited:
Michaelbluewolf said:
Hello Again,
I used a spare drive shaft end that I got from the guy I bought the Mercrusier engine from. I adjusted the rear and front engine mount till the shaft seemed equally centered in the gimble bearing and then installed the outdrive. I used a lot of grease on the input shaft on the outdrive, I stuggled with this for quite awhile, untill the O/D finally slipped in enough and then tightened the 6 retaining nuts and torqued them down.
Does this sound like this could be the problem. Could the O/D C/V shaft be causing this noise and if so what would be the next move.
Thanks to 270win and moparlvr4406
P.S. The noise is a consant rotational sound, More like a drive shaft support bearing that going bad.
Click to expand...
IMO- The alignment tool is a much have, from the sound of it you got it close, but had to torque it the rest of the way, any binding due to mis-alignment could cause an issue. There could be another issue like a bad coupler, but without using the alignment tool you just won't know if it's an alignment issue or a defective part. I've always been able to get my drives on completely and then torque the retaining nuts once the drive is mated to the bell housing. The constant sound would indicate a coupler to me. But proper alignment would be my first step.
 
Good luck, post what you find out.
 
I would say check alignment with an alignment tool as 270win stated.
Hopefully it's something simple like a coupler or gimbal bearing.
Just throwing this out there but could it be a rear main in the engine?
 
I've never heard a rear main make a constant sound, usually they're very rhythmic, loud and deep knocking.
 
That doesn't sound like flappers to me...sounds deeper and metallic.

I like the idea of running it with the drive off since you'll be doing that to recheck alignment. Just remember to create an alternate incoming water supply since you pick up cooling water through the drive that won't be there.

If it's quiet with the drive off, I'd be looking at drive shaft u joints first with the coupler next. You said that the coupler looked good from the standpoint of the rubber, but did you inspect the internal splines for wear?

As mentioned, if alignment is correct you shouldn't need to draw the drive into final position using the nuts. That's a red flag.

Buy or borrow an alignment tool and read up on how to use it. Getting that right is a two man job that can take time. It's no place for a shortcut.
 
The water flapper was actually missing. Would my sound be because of the missing flapper?
 
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