Ticking noise near drive shaft

[CMAC]

My mecruiser is producing a tick tick tick sound that appears to be coming from the area near the drive shaft going from the motor into the outdrive, but it is hard to identify the exact location. The rate of ticking increases as the engine rpm increase. At about 1500 RPM the ticking becomes hard to hear due to engine noise and increase frequency. It makes no difference whether the engine is under load or turning. Any ideas on the cause of this noise?

Thank you. Clint

 

[FreeBeeTony]

Re: Ticking noise near drive shaft

Maybe the exhaust flappers?

I had a similar noise...........was more apparent at idle though

 

[CMAC]

Re: Ticking noise near drive shaft

Maybe the exhaust flappers?

I had a similar noise...........was more apparent at idle though

 

[CMAC]

Re: Ticking noise near drive shaft

Maybe the exhaust flappers?

I had a similar noise...........was more apparent at idle though

 

[CMAC]

Re: Ticking noise near drive shaft

I'm not sure if my reply went through - I'm new to this computer forum.

I hadn't thought of the exhaust flaps. I was thinking the gimble bearing.

The noise is more apparent at idle.

Thanks,

Clint

 

[FreeBeeTony]

Re: Ticking noise near drive shaft

Is it a V8?.

Mine were pretty easy to check........

Could also be the lower shift cable hitting the coupler.

 

[CMAC]

Re: Ticking noise near drive shaft

It is a V8.

I will check the shift cable.

The exhaust flaps only have abour 80 hours on them. I recently put in a new rebuilt motor and dealt with other items like the flaps. The ticking was there from the get-go, but seems to have gotten worse with time.

What do you think about the gimble bearing theory? Is that off base?

 

[Don S]

Re: Ticking noise near drive shaft

80 hours doesn't mean a thing. All it takes is one overheat due to lack of water, and with the old style exhaust flappers the rubber burns off the SS flapper and they make noise. But, usually you don't hear a flapper above idle unless you have a leaky/stuck exhaust valve causing the engine to suck the flapper closed each time that cylinder goes to intake cycle.
Could also be a gimbal bearing. Pull the drive and check it. Any roughness could cause a noise. Same with the ujoints.
Could also be a chipped gear in the upper section of the outdrive. The noise would be heard from the back of the engine.
Could also be a noisy valve lifter.
We can't hear the noise, or hear where it's coming from. Best thing to do is start the engine, stick your head in there an listen. Use a mechanics stethiscope (less than 10 bucks from an auto parts store) to listen. Or use a long screwdriver with your ear on one end.

 

[CMAC]

Re: Ticking noise near drive shaft

Hi Don,

Thanks for the advice.

I took a pipe and listened around the other day. I was only able to isolate the sound to the general area around the drive shaft. I was unable to find the exact spot where the noise was coming from.

The sound seems metallic to me and has some rhythm, but is not perfect rhythm. Would the metallic sound eliminate the flapper as an issue?

I'll pull the drive to check the gimbal bearing and U joint in a few days.

Thanks.

Clint