00' 4.3 Mercruiser Wierd Engine Noise

[scottnpeter]

Alright so to start off I have a 00' Bayliner 4.3 mercruiser. To sum it up the engine idles and runs really well except there is some wierd noise. Its very difficult to describe it. It is a cross between a rattling and squicking noise. I just had the starter replaced, , spark plugs changed, timing adjusted, and carb rebuilt last year. Any help would be awesome.

 

[Don S]

Re: 00' 4.3 Mercruiser Wierd Engine Noise

Did it do this before all the work you listed? Who adjusted the timing? Do they understand base timing mode and Thunderbolt V timing? Does the timing advance work? How about the knock sensor system?

Your noise sounds like pre ignition/detonation/ piston melt down. so be sure about your answer.

 

[Bondo]

Re: 00' 4.3 Mercruiser Wierd Engine Noise

Its very difficult to describe it. It is a cross between a rattling and squicking noise.

Ayuh,... When,+ How is this Noise coming about,..??
Sometimes,..??
All the time,..??
1/2 throttle,..??
Full throttle,..??

 

[z284u2try]

Re: 00' 4.3 Mercruiser Wierd Engine Noise

Please tell me that you don't have a plastic power steering pulley.
Shott some belt dressing on the pulley and tell me if it goes away.

 

[scottnpeter]

Re: 00' 4.3 Mercruiser Wierd Engine Noise

I had the work done at the place I bought the boat from. I was confident that they knew what they were doing. The sound occurs all the time, although you cant really tell at full throttle with all the noise. I was thinking it might be something with one of the pullies too. I'm going to go ahead and shoot it with some belt dressing.

However I'm thinking the distributer might be the overall problem. The shop just adjusted the timing on it (after I had already re-built it). I'm thinking of replacing it if the belt dressing doesn't do the trick. What do yaal think?

 

[Bondo]

Re: 00' 4.3 Mercruiser Wierd Engine Noise

What do yaal think?

Ayuh,... Observation,+ Diagnosis is a Much Better Idea....
It saves a Ton of Money, rather than replacing Good Parts...

If it's the plastic pulley, No amount of belt dressing is going to do a damn thing...
It needs replacing...
And,...
I've never heard a Distributer make abit of Noise....

 

[z284u2try]

Re: 00' 4.3 Mercruiser Wierd Engine Noise

The belt dressing suggestion was to let you know if it quits up that you have a problem in your pulleys. No amount of dressing will fix a plastic power steering pulley. Do you have too much tension on the serpentine drive from the manual tensioner?

 

[scottnpeter]

Re: 00' 4.3 Mercruiser Wierd Engine Noise

Ya you are right, observation and then diagnosis is a much better idea. I didn't think that the distributer itself was making the noise but that the timing on it was casuing the noise. Is this possible?

Ill have a look at the pulleys this weekend and let you know if I find the problem. With that said, do you have any general suggestions for knowing if the pulley is shot?