White Smoke while running on muffs

[jonnyquest67]

I have a 72 Mercruiser 165 that is in need of some TLC. This boat was in the water once last year, then pulled and left to sit outside (luckily, the weather in the central valley of CA is mild). It has had new plugs & wires, the oil and oil filter changed, and a new fuel/water separator filter. It was a little hard to start, but fired up after a while. It runs okay, but I seem to be getting more than a little white smoke through the exhaust. Is it normal to get white smoke while running on the muffs? I realize the answer is probably no, but I am hoping against hope here. We will be on a houseboat for several days over Labor Day, and would love to use this boat as our runaround.

Any suggestions or comments are greatly appreciated. Thanks in advance!

 

[Don S]

Re: White Smoke while running on muffs

It may be as simple as needing a new raw water pump impeller. If there is very little water flowing thru the exhaust, it will turn to steam quicker (aka white smoke), or maybe a plugged riser or manifold.
May also be water getting into the cylinders from a crack or bad gasket. Pull the spark plugs and see if any plugs look new, as in not run at all.
You could also do some other tests like compression & leakdown if you do have water in a cylinder.

 

[jonnyquest67]

Re: White Smoke while running on muffs

Thanks, Don. I just started it again and noticed it was running very hot, up around 200 - 210 degrees. This is way too hot, even for muffs, isn't it? Does this tend to point to the impeller? I doubt it has been changed recently...

How difficult is this to change? I guess its back to the dealer to search for a manual...

Thanks for the help. Obviously, I'm a newb with boats, but I'm pretty handy and an okay troubleshooter. More tools would help, I'm sure!

 

[Don S]

Re: White Smoke while running on muffs

You can down load the OEM service manual at the link below, if you have a fast internet service, it's just over 1GB in size.

http://www-alt.mercurymarine.com/mnetdata/SERVICE/CRUISER/Servmanl/01/cover.pdf

 

[Don S]

Re: White Smoke while running on muffs

Over 140? is too hot on muffs.
It could be impeller, exhaust, or several other things. First thing in any overheat problem on a boat is check the raw water pump impeller. It's between the upper and lower units of your outdrive.

Here is some other info on your drive and water pump.
http://www.mercstuff.com/howdoi.htm

 

[jonnyquest67]

Re: White Smoke while running on muffs

Thanks for all of your help. It looks like I have some serious work to do on this, before I haul it 4 hours away and try to run it for several days.

Two things I'm always lacking (like everyone)... time and money. Probably should have told the wife no about the boat!