5.0l mercruiser 2003 670 hrs puffer

[Frank514]

Hello just purchased my boat without knowing shes a puffer on cold start. Smokes for about 40 seconds and then stops. Does not burn alot of oil , i believe its a drop or 2 threw a stem seal. What would you recommend to stop this issue?
Oil additive or change oil type? I currently run with 25w40. Thanks in advance.

 

[Bondo]

Ayuh,..... Welcome Aboard,..... Do a compression, 'n leak down test to see what it's general condition is,......

If it's valve seal/ valve guides, get the heads rebuilt,.....

Changin' to a different oil, or addin' snake oil won't fix anything,....

 

[Frank514]

Ayuh,..... Welcome Aboard,..... Do a compression, 'n leak down test to see what it's general condition is,......

If it's valve seal/ valve guides, get the heads rebuilt,.....

Changin' to a different oil, or addin' snake oil won't fix anything,....

I got a great hearted honest mechanic the engine runs like new its just on start-up it puffs 80 percent of the time compression is good.. I wanted to fix that problem and my mechanic said not to worry bout it. Its not worth the cost of doin a fix told me to live with it you would be happier lol . Just trying to find if there is any other way with everyones knowledge. Thank you for your reply much appreciated.

 

[Lou C]

If it does not smoke enough to foul spark plugs then you can use it that way but it is possible to replace the valve seals on a Chevrolet small block without removing the cyl heads, there are a few different ways to do that, if you search on you tube you will see.
I put a pair of reman cyl heads on my Chevrolet V6, cost was about $450 for both, gaskets about another $100, in this case if you have good compression I'd try valve seals first.

 

[Frank514]

If it does not smoke enough to foul spark plugs then you can use it that way but it is possible to replace the valve seals on a Chevrolet small block without removing the cyl heads, there are a few different ways to do that, if you search on you tube you will see.
I put a pair of reman cyl heads on my Chevrolet V6, cost was about $450 for both, gaskets about another $100, in this case if you have good compression I'd try valve seals first.

Thanks much appreciated

 

[Scott Danforth]

agree on the compression numbers and leakdown test

stock valve seals on GM motors really do suck. I would simply swap them ($30 plus your time) takes a screw style valve spring compressor

or pull the heads and have them refreshed at about $150 each.

 

[Frank514]

agree on the compression numbers and leakdown test

stock valve seals on GM motors really do suck. I would simply swap them ($30 plus your time) takes a screw style valve spring compressor

or pull the heads and have them refreshed at about $150 each.

Thnx. I live in montreal quebec and it seems like there is no real motor heads willing to just fix this issue without charging me for a whole engine job thats not really needed. Thnx for the feedback.

 

[matt167]

At heart, it's a small block Chevy. It could be in a 1932 Ford hotrod or a Corvette, but it's in a boat hooked to some marine parts.. You will find guys if you search and find someone open minded. It's a job that can be done by pulling the valve covers and applying shop air to the cylinders... BUT lots of SBC's smoke at startup. I have an '85 Corvette with 88k miles, yup it smokes at cold startup. Let it warm up and it's all good.

 

[Lou C]

Thnx. I live in montreal quebec and it seems like there is no real motor heads willing to just fix this issue without charging me for a whole engine job thats not really needed. Thnx for the feedback.

Look up Nicks Garage (Indy Auto) in Laval QC if he can’t do it I’m sure he can refer you to someone who can.

 

[Scott Danforth]

Thnx. I live in montreal quebec and it seems like there is no real motor heads willing to just fix this issue without charging me for a whole engine job thats not really needed. Thnx for the feedback.

they sell tools in montreal. do it yourself and save money.

https://www.amazon.com/OTC-4573-Universal-Overhead-Compressor/dp/B000F5HUUI

or if you prefer adds from your local auto parts store https://www.princessauto.com/en/universal-overhead-valve-spring-compressor/product/PA0008261604

then all you need are GM valve seals for a Gen 1 SBC