3.0 mercruiser smoke from rocker breather

[jon middleton]

Hi

I have got a 3.0 mercruiser and have recently changed the head gasket and the boat runs great now but there is some smoke coming from the rocker cover breather is this normal or do i have a problem?

Any help would be great

thanks
Jon

 

[Bondo]

Re: 3.0 mercruiser smoke from rocker breather

Ayuh,... Odds are the Rings are tired,... Run a compression test to tell...

 

[jon middleton]

Re: 3.0 mercruiser smoke from rocker breather

the boat is 2002 year would the rings be worn it that year engine? Would adjusting the tapits help as they making a bit of a noise?

Jon

 

[Bondo]

Re: 3.0 mercruiser smoke from rocker breather

the boat is 2002 year would the rings be worn it that year engine?

Ayuh,... It'll depend on how it's been Abused over the last 7 years...

Would adjusting the tapits help as they making a bit of a noise?

The valves have to be properly adjusted to stop the clatter, but it really doesn't have much to do with Blow-by.....

 

[jon middleton]

Re: 3.0 mercruiser smoke from rocker breather

the boat has not done that many hours, as it is only used from May to September, it did not have the smoke before I changed the head gasket, Could i have done something when changing the head gasket to cause the problem, or could it just be excess oil in the tube getting hot ?

thanks
Jon

 

[Bondo]

Re: 3.0 mercruiser smoke from rocker breather

the boat has not done that many hours, as it is only used from May to September,

Ayuh,... 1 good Overheat is enough,... regardless the total hours...

it did not have the smoke before I changed the head gasket, Could i have done something when changing the head gasket to cause the problem, or could it just be excess oil in the tube getting hot ?

Did you have the head Checked,+ rebuilt,..??
Excess oil in What tube,..??
Why were you changing the Headgasket,..??

 

[jon middleton]

Re: 3.0 mercruiser smoke from rocker breather

Hi

We changed the head gasket as plugs 1 and 2 were cleaning, and sure enough the valves on cylinder on 1 and 2 were white when we took the head off. The head was check and no cracks.

The tube is the one going from the top of the rock cover and has a flat metal piece that attaches to the top of the carb , I guess that is the breather ??

Thanks
jon

 

[Bondo]

Re: 3.0 mercruiser smoke from rocker breather

or could it just be excess oil in the tube getting hot ?

Nope....

Looks like We're back to a Compression Test...

 

[jon middleton]

Re: 3.0 mercruiser smoke from rocker breather

thanks I'll get the compression check done tomorrow and see what is tells me

Thanks for your help so far

Jon

 

[CharlieB]

Re: 3.0 mercruiser smoke from rocker breather

Any chance that this boat has been used in SALTWATER for most of those seven years?

When you changed the head gasket did you inspect the old gasket and find signs of leaking?

If water was 'cleaning' 1 & 2 you may need to pressure test the exhaust manifold to be sure that is NOT leaking water back into those cyl's.

I seriously doubt that changing the head gasket has contributed to your b;ow-by, you are just now paying more attention to the motor and noticing how much b;ow-by it has.

Some blow-by is normal and progressively worsens as the motor ages.

A compression test is the first step in determining if you have a potential problem growing, if the numbers are falling, nearing 100 psi, then follow up with a cyl leak down test to determine the percentage of leakage past the rings.

Are you still able to maintain WOT RPM?

 

[jon middleton]

Re: 3.0 mercruiser smoke from rocker breather

Hi Charlie,

The boat has been in saltwater for seven years , when I changed the head gasket there we definite wear on the gasket hear the water passages and the head bolts were very easy to undo and were definately not tighened to the correct torque. I am hoping it is not the manifold as i replaced that and the elbow at the same time.

The boat still go very well and maintain WOT RPM easily

Am I just being paranoid?
Cheers for any help you can give

one other question is ? the breather pipe is that the yellow one that goes into the carb, the one that has gas/smoking coming out of it just bolts to the top of the flame arrestor?


Thanks

Jon

 

[bruceb58]

Re: 3.0 mercruiser smoke from rocker breather

I am hoping it is not the manifold as i replaced that and the elbow at the same time.

Charlie can correct me if I am wrong here but I think what he was suspecting was that your original problem was not the head gasket at all but it was the manifold leaking that was causing the cleaning.

I wouldn't worry about the smoke. It is very normal and the reason the tube goes up to the carb in the first place.

 

[jon middleton]

Re: 3.0 mercruiser smoke from rocker breather

thanks for all your helps guys im off to the boat today so I will have another look and let you all know the outcome

thanks
Jon