bertram31.com

I'm hoping you guys can steer me in the right direction developed a new noise in the trans it sounds like when a bearing goes bad I thought it might be a cutlass bearing but it's in the trans.Before I have it yanked anything I can do or check.Shift in and out of gear no problem running no problem.As allways thanks for any input. Bill G.

If this is only at idle, check that all the cylinders are firing.
Al

only in gear

Bill G. wrote:only in gear

Yes, but does the rattle come at idle only. If you bump the rpm up 100, does the noise stop? I don't know anything about trannys, but that rattle at idle speed says to me that a cylinder is not firing.
Al

Didn't try that but the noise is not a rattle more of a bad bearing noise

Could be the drive plate on the flywheel.....springs broken.....and a misfire will amplify the problem.

Do you have metal in the oil???

Harry

Harry thanks ,I change the fluid every year it's clean no metal that I could see.

For a bearing to be making as much noise as you described you should be seeing some metalic flakes or particals in the oil.

H

Maybe this will peek someones memory...but I believe I have had a squeal come from the gearbox on two different occasions. I think it was those trannies...

One was a hose was being squashed not allowing the fluid to flow until RPMs came up and put some pressure in the hose.

Second was an issue with the Shifting Shaft. The lever the cable gets mounted to is attached to a shaft. I do not recall if it was worn...had a bad seal or what...but when shifting it would squeal at low RPMs. I believe it entailed removing a cover held in place by two or three 1/4" bolts and pulling the shaft out. I ordered a new one, installed and that was that.

Can you hear it when idling in gear vs neutral?

Try taking the engine up to 2,000 rpm with the gear in neutral. If the noise persist with the gear in neutral it may be an internal bearing issue.

The difference is thrust loading. The only time the bearings have no thrust load on them is in neutral. The thrust load is created at the prop and transferred into the gear via the shaft. The thrust may be loading the bearing, and stopping the noise....but when there is no load on it, the ball bearings rattle around between the race and the cage.

It is not uncommon for bearings to rattle under no-load conditions, and stop once they are loaded up.

Good luck

Thanks Scot the noise is while in gear

Hey Harry good call it is the damper plate and a broken spring TXS for the help...........Bill G.

When a spring went in my damper I thought the tranny / motor was coming apart. Last thing that came to mind was a bearing. Guess its different from boat to boat.

Glad Harry put his finger on it.

Gotta love this place.

Cool deal! ! !

And THANKS for the follow up......

Glad you got it fixed

H

We'll call this one "Harry knows best". Glad you found the problem.

I need to add to this discussion because I just lived this scenario a few days ago.

Last month, I had some friends down from the west coast. We drove down to the keys for a few days and a couple of days before they left, I took them for a howdy cruise up the Caloosahatchee river to the railroad trestle. One the way back down the river, I wasn't paying attention and strayed out of the cannel between the sticks and found myself shining my props in the mud. No physical damage and I got us back between the sticks and brought her home. A week later, I went to Alaska for two weeks, so when I got back I put the Bertram in the water and fired her up.

There was a hell of a racket coming from my port engine hold and didn't get much better as she warmed up. So I listened and concluded that the noise was coming from the tranny and thought the worse about running into the mud.

So I checked the fuel filters and then took the cover off the intake and found carbon galore. Then I put my scanner on and found no errors, but the rpm was all over the place. The plugs were almost new and were the latest platinum tipped and I had new wires on too.

I put some Sea Foam into the tank and fired her up and poured about a cup into the intake then shut her down for 10 minutes. I repeated the process twice more and the engine ran like she should. With the engine running smooth, the transmission was quiet. The noise only came during idle, but now she idles smooth at 620 rpm where before she was at about 575.

Now I just need to find out how it got that way in the first place. My guess is ethanol.

That's my story and I'm stickin with it.

Dick

Dick
I'm gonna first say that I am strictly GUESSING here but......I can only imagine that carbon formation in the intake would be coming from crankcase venting into the intake or some exhaust recirculating back thru the intake.

My take on the tranny noise is just as Al stated, the engine was either misfiring or for some reason running roughly causing a worn drive plate to generate noise.

The good thing is that drive plates are not very expensive......just a pain to change in our Bertrams

H

Harry,

The outside of the air filter on the intake where the vent tube from the valve cover is attached was covered with carbon. Your guess is probably correct. I hope to get back to it this afternoon and see if I can find out why there is so much carbon in the vent.

Dick

Might not be carbon........

Check the "Stuff" on the air filter to make sure its what you think it is......I had a similar problem but my "Flame Arrestor" would get covered with Belt Dust.

I removed my old rusty pulleys and installed new aluminim ones and my belt dust problem went away.

Material coming out of the valve covers should be just an oily mist but not viewed as carbon.

Harry

Harry,

You are either a genius or you've had everything imaginable happen to you. I got to thinking about the belt on that engine and your comment about belt dust. It has been noisy for a long time and I've been babying it all along for the past three years. Every time it squeals, out comes the can of belt dressing.

Anyway, I looked at the situation and removed the aluminum Mercruiser filter and took it to my utility sink and hosed it down with K&N cleaner. It was filthy with black. A lot of it was carbon, but most of it was little black particles that would not smear like carbon.

So I looked at the path of this stuff. Mercruiser has this cover that goes over the intake from the heat exchanger forward to the distributor on the rear. All the air going through the air filter comes from either the back or forward. So I looked at stuff forward of the filter and sure enough, there was a lot of belt residue. It was also all over a starboard fish cleaning station I kept down in that engine hold.

I figure that the belt dust clogged up the filter and then the engine ran rich and eventually coated a lot of the intake with carbon.

So I replaced the belt since I had two of them below deck among other things and hope that this little episode will be long remembered.

I'm taking a trip up the river in a couple of days to continue running the Sea Foam through the engines.

Thanks for the tip. This is the greatest site.

Dick

Dick
Check your pulleys. If the pulleys are steel, rough and rusted, they will eat your new belts in pretty short order.....then your right back to square one.

Good luck

Harry