1998 5.7 srartup

[Myride85]

Sat for a month. First start up. After watching the video. I should have smelled it. But didn't. Would this be normal the smoke? It did go away after 15-20 sec or so. Or 30 sec.
Motor less than 500hrs.

 

[ScottinAZ]

Sat for a month. First start up. After watching the video. I should have smelled it. But didn't. Would this be normal the smoke? It did go away after 15-20 sec or so. Or 30 sec.
Motor less than 500hrs.

appears to be bluish in color, if it did it after sitting for a month, you could be starting to get leaky valve stem seals/guides (some have seals, most do not). if the engine is otherwise healthy, its more a nuisance than a problem at this point.

 

[achris]

appears to be bluish in color, ... leaky valve stem seals/guides ... its more a nuisance than a problem at this point.

Took the words out of my mouth...

 

[Drcoffee]

Exhaust vlave stem seals will harden faster over time than intake seals, due to the higher heat over time and let oil leak into the cylinders. Blue smoke on start up is the sign of oil in the cyl. I’ve replaced valve springs and stem seals before. Its very doable for diy. Once the locks are removed, the seal pops off, pop on a new seal, replace locks, and release the spring. 16 per side on a v8. Use compressed air to keep the valve closed. You can do just the exhaust valves, but might as well do them all. Another option is adding marvel mystery oil to your next oil change to help clean off the coked oil on the seals. Might make it smoke more if the old oil is actually part of the sealing surface. LOL or something like AT205 to help rejuvenate the seals and make them pliable again. Both are temporary of course.

 

[Lou C]

Just keep an eye on oil consumption, does it foul spark plugs?

 

[Myride85]

Sorry forgot to mention. I'm looking to buy this. 1998 sea ray 250 sundancer

 

[Drcoffee]

Was it fogged prior to being put away? Or just sitting for a month after normal use?

 

[Myride85]

He said it was last used about a month ago. I did watcha video of another 5.7 at start up and it did the same thing.
But the engine in question ran so smooth. No shake, shimmy, or rattle or pop. Ran cool as can be. Risers were actually cool to the touch.

 

[ScottinAZ]

if its the original engine, its 24 years old. Not unusual for the seals to have become plasticized in that timeframe, and are no longer up to the job at hand. If the engine otherwise runs good, and shows minimal other signs of age, it wouldnt bother me, as long as the price reflects the condition of the boat. As stated earlier, its more a nuisance than a major issue, as long as it isnt causing other issues (plug fouling for one) YMMV of course

 

[Myride85]

Thank you all for the responses. It's a good price and in great condition. Understand it's 24yrs old. It's not brand new. But bought a 22ft four winns last year that ending up effin me in the end. So I'm very cautious now.
This would be my dream boat

 

[Scott06]

Thank you all for the responses. It's a good price and in great condition. Understand it's 24yrs old. It's not brand new. But bought a 22ft four winns last year that ending up effin me in the end. So I'm very cautious now.
This would be my dream boat

Does the engine have decent compression, and no water in The oil? Would water test it before buying.

 

[Myride85]

Tha

Does the engine have decent compression, and no water in The oil? Would water test it before buying.

That didn’t get done on this visit. He is willing to take me out on the river and test drive it. Ummm yea!! LOL

 

[Drcoffee]

Thats a lot of heavy smoke. I would pass on it if it were me. My 5.7 has 550 hrs and only smokes on seasons first start up When it clears the fogging and even then the smoke is more white. That much oil will foul your plugs and run poorly. Plan on rebuilding it.

the first thing I did when I bought my boat was to send the motor oil out for analysis. It came back clean and the oil that was in it was black as night.

 

[Myride85]

Thats a lot of heavy smoke. I would pass on it if it were me. My 5.7 has 550 hrs and only smokes on seasons first start up When it clears the fogging and even then the smoke is more white. That much oil will foul your plugs and run poorly. Plan on rebuilding it.

the first thing I did when I bought my boat was to send the motor oil out for analysis. It came back clean and the oil that was in it was black as night.

Never heard of sending oil out for analysis. Intrigued

 

[Drcoffee]

Never heard of sending oil out for analysis. Intrigued

Oil Analysis | Blackstone Laboratories

Learn what's going on in your engine with oil analysis. Our free kits are easy to use and we explain the results in plain English! Since 1985.

www.blackstone-labs.com

Its about $30

 

[Lou C]

Very good to do if you’re thinking of buying

 

[stang32]

its a 25 year old boat, it will have some oil burning issues. as stated prior, is all else is good, just accept it, if the engine runns smooth, has plenty of power and the price is right, go for it

 

[Drcoffee]

Might want to take a multimeter next time. You are a high idle but the volt meter is low at 13v. Should be at 14v at that rpm. Either a weak battery or alternator issue.

I keep watching the smoke video, that is too much smoke for too long to be valve seals. That looks more like bad piston rings. A compression test really should be done. When it comes down to it, a bad power plant can turn this boat into yard art. Nothing in boating is cheap or easy.

 

[achris]

.... Nothing in boating is cheap or easy.

And we usually find out the hard way...

 

[tango13]

My old carbed 5.7 would smoke like this for several minutes until the choke opened while warming up…. otherwise I never had issues.