Please help with noise...video included

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4runneradam

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So I have this 1984 Chris Craft Scorpion 210 with Mercruiser 228. Been sitting since 2005. Previous owner supposedly kept up good maintenence, but was put in the hospital and could not use it so it was parked in 2005. Forward to a few months ago. I rescued it. Changed oil and fuel filters, cleaned out fuel tank, and looked it over real good. Ran good on muffs, except a ticking noise from the valve cover. Popped it off and found 2 pushrods bent. Straightened them out, reinstalled, compression was only 90psi. Still runs good. Ran her on muffs for a while, reved to 4k, rechecked pushrods and compression, still OK.

Took her out on the river, and it did great. No problems.

A week later, fire it up, and the noise happened. Its a loud clanking, coming from the rear of the engine, at the bellhousing. Can't be heard from behind the boat, just inside. Quiets down substantially above 2500rpms to where it seems like its gone. I first though it could be the exhaust shutters, but I took them out and its still there. I greased everything up really good, no change.

Here's a youtube link to the video. Sorry for the screwed up video half way through, my phone sucks. But the audio came through.



What could it be? Gimbal bearing? Something loose in the bellhousing?
 
Bondo

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Re: Please help with noise...video included

Ayuh,.... Private vid, can't see nothin',...
 
achris

achris

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Re: Please help with noise...video included

Yep, you need to go back into y-tub and change the status of the video to 'Public'....

Chris.....
 
achris

achris

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Re: Please help with noise...video included

ARRRRRRR, that sounds dreadful... Turn it off!!! Pull the drive and have a look... Run the engine without the drive... I SUSPECT the drive shaft housing gears are shot.... But you need to do more checking...

Chris.....
 
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4runneradam

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Re: Please help with noise...video included

Im new to inboards...but are you talking upper unit gears? Wouldnt i hear it from outside the boat?
 
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4runneradam

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Re: Please help with noise...video included

Im talking on the flywheel of the engine. How does the driveshaft hook up to the flywheel? Some sort of coupler i assume?
 
NHGuy

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Re: Please help with noise...video included

There are two sets of universal joints in the bellows, there is a coupler on the back of the flywheel.
Chris, who really does know this stuff, said to pull the drive and start the motor for a moment. If it's quiet as expected, then check the drive. He said maybe it's noise in the gears in the upper drive. I'd say he knows the quickest way to diagnose the problem.
 
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tinkerguy70

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Re: Please help with noise...video included

4runneradam said:
Im talking on the flywheel of the engine. How does the driveshaft hook up to the flywheel? Some sort of coupler i assume?
Click to expand...

Yes, the driveshaft is connected to the engine through a coupler. No, they don't sound like that when they go bad.
You must pull the drive before you go any further. It's really not hard to do at all.
 
NHGuy

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Re: Please help with noise...video included

The drive shaft is splined and it sticks through the gimbal bearing (in the transom) into the coupler. That's how it attaches to the coupler. The gimbal bearing acts as a carrier bearing. It's called gimbal because it can pivot to get a proper angle to the coupler.
 
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4runneradam

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Re: Please help with noise...video included

OK, I'm not trying to argue with anyone, obviously you guys know a lot more than me. But if the problem lies within the outdrive, then why cant I hear anything standing behind the boat looking at the outdrive? All the noise is inside the boat.
 
TheHunter990

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Re: Please help with noise...video included

If you have a bolt thats flying around in the bellhousing (which is what that sounds like to me), you need to pull the drive anyways.
You need the drive off to slide the engine forward to split the engine/bellhousing.
At the same time check the ujoints and gimbal as they are suspects as well.

Also with the drive off you can try to look through the gimbal bearing for any foriegn objects.

If it were me, I would have took the drive off before you even started it for the first time. 8 years of sitting is a long time.
 
RogersJetboat454

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Re: Please help with noise...video included

TheHunter990 said:
If you have a bolt thats flying around in the bellhousing (which is what that sounds like to me), you need to pull the drive anyways.
You need the drive off to slide the engine forward to split the engine/bellhousing.
At the same time check the ujoints and gimbal as they are suspects as well.

Also with the drive off you can try to look through the gimbal bearing for any foriegn objects.

If it were me, I would have took the drive off before you even started it for the first time. 8 years of sitting is a long time.
Click to expand...

Not only this ^^^
But pulling the drive is considered annual maintenance to check the bellows for water, check the U-joints, grease the drive shaft splines, check the gimbal bearing, and check the engine alignment. The drive needed to be pulled off.
 
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4runneradam

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Re: Please help with noise...video included

I understand all that. I should have mentioned, that I plan on tearing it down after this season to replace the gimbal and all bearings. I just wasnt planning on doing it right now.

I have driven the boat with this noise for several hours, the noise has not gotten louder or quieter. Seems to go away above 2500rpm.
 
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Gator1996

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Re: Please help with noise...video included

I had a similar sound, took the drive off and ran it again. No change, I finally determined that the starter gear wasn't fully disengaging after starting the motor. The only original symptom, before the sound was the starter had been dragging and was turning the motor very slowly. Replaced the starter, noise gone.

It wasn't quite as loud as yours sounds as I recall but was definitely similar and from the same area of the motor. I posted a video sometime back.
You might take a look. Good luck.
 
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4runneradam

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Re: Please help with noise...video included

Thanks! I watched your video and read your thread. I'll pull the starter and give it a once over.
 
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