1985 454 V8, Model 340, started blowing white smoke out of the exaust upon starting

justtls06

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Jun 12, 2006
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I have a 1985 Chris Craft Commander that has been well taken care of with regular maintenance oil changes etc. Unfortunately it has not gotten a lot of use for the last couple of years. I have however started the engines and let them come up to running temp a couple times a month and I have not had any issues whatsoever. Yesterday both engines started up easily as usual but the starboard engine starting smoking immediately out of the exhaust, mostly a white smoke. I added some marine fuel stabilizer thinking it could be moisture but it didnt help. Within a few minutes the engine was overheating and I had to shut it down. I checked the oil and it looked actually cleaner than the other engines oil and had no sign of water or milky quality at all. All I can think of because it appeared to happen right from the start is that the head gasket is just old. Also a quick note, the compression on this (Starboard Engine) is about 20% lower than the (Port Engine) This boat is or was in really good shape, any help to get it back up to par would be greatly appreciated, thanks.
 

hivoltg

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Re: 1985 454 V8, Model 340, started blowing white smoke out of the exaust upon starti

I would first check to make sure you dont have a leaking exhaust riser. When you remove the riser from the manifold you can check for the tell tale rust streaks. You can also pull the sparkplugs and check for rust on them. I would verify that isnt the cause of the white smoke before I checked the head gaskets. This wouldnt cause overheating tho...hmm.
 
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justtls06

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Re: 1985 454 V8, Model 340, started blowing white smoke out of the exaust upon starti

Also, the oil looks ok, thanks for your time.

TLS
 

Bondo

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Re: 1985 454 V8, Model 340, started blowing white smoke out of the exaust upon starti

Ayuh,.... Welcome Aboard,... it Overheated, so start there,...

It must have a raw water impeller pump,... Pull it, 'n rebuild it,..

Pull the risers, 'n Check the exhaust manifolds too,...

Water has to get Into the motor, 'n then Out, through the exhaust,...
 

NHGuy

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Re: 1985 454 V8, Model 340, started blowing white smoke out of the exaust upon starti

Yah, to explain. IF there's a water pump failure or supply failure the little water that is in the motor gets turned to white steam as the motor goes hot. You might be lucky and that's all you need to deal with, there's every chance that the raw water pump has failed.
Don't worry about the head gasket(s) yet. It's not a pressurized cooling system like a car. When a head gasket fails with a pressurized cooling system, coolant can get in the combustion chambers and cause white smoke.
 
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Volphin

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Re: 1985 454 V8, Model 340, started blowing white smoke out of the exaust upon starti

Yah, to explain. IF there's a water pump failure or supply failure the little water that is in the motor gets turned to white steam as the motor goes hot. You might be lucky and that's all you need to deal with, there's every chance that the raw water pump has failed.
Don't worry about the head gasket(s) yet. It's not a pressurized cooling system like a car. When a head gasket fails with a pressurized cooling system, coolant can get in the combustion chambers and cause white smoke.

Uh, no. If he is running a closed cooling system the coolant will be under pressure at operating temperature. I'd do another compression test and verify the numbers are not 15% away from each other and check the pump operation as well. It doesn't matter if the compression is slightly lower on port vs starboard engine. What you are looking for is if they are all somewhat equal on that engine only.
 
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