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View Full Version : White Smoke / Leaking Exhaust Manifold? <Pictures included>


snivesatgt
10-12-2008, 11:40 AM
I have a 88 prostar 190 and when it's running - there is white smoke that is coming out of the back. Before it would only happen when it got hot from a full days worth of running. Now it happens (and keeps having a small amount) after about 1-2 sets.

I am worried my exhaust manifold gaskets may be leaking water into the engine ignition - causing it to burn off as steam. I'm not sure if this even makes sense though - I am not too familiar with the indmar setup for manifold cooling.

Here are pictures of the two exhaust manifolds. The rust stains make me think there is a leak.

Any thoughts on either confirmation of the idea - or suggestions/comments on that it may not be that and other ideas.

Thanks,
Ben

JimN
10-12-2008, 12:02 PM
First thing I would look at is the raw water pump impeller and the oil cooler. The motor really shouldn't go past normal operating temperature when it's running, even if it's a full day. If the temperature increases over time, I would say that the cooling system isn't working correctly. If the water was getting into the culinder(s), you'd have a power loss but if some reaches the hot exhaust sooner than normal, The exhaust manifold leaking could cause the symptom.

snivesatgt
10-12-2008, 01:43 PM
Where and how do I check the oil cooler?

I check the fresh water intake quiet often - and that is good to go.

While the boat is running it's staying in the 160's or so (plus or minus 10).

After doing a set and turning it off, it will sit for a bit and right when it starts - be around 200-210 and quickly go down to 160.

I always asssumed this was normal since it's running around 2300 RPMs wakeboarding for 15 minutes and then is turned off.

Thanks,
Ben

JimN
10-12-2008, 01:45 PM
The oil cooler is the black metal cylinder near the hull fitting where raw water comes in and has two hoses connected to the transmission. You would need to loosen the hose clamp on the hull end and slide the large hose off, then check for twigs, leaves, weeds, etc. The part where you're checking the fresh water intake is the oil cooler.

The temperature rising after it's shut off is called 'heat soak' and is normal.

TMCNo1
10-12-2008, 01:53 PM
I have a 88 prostar 190 and when it's running - there is white smoke that is coming out of the back. Before it would only happen when it got hot from a full days worth of running. Now it happens (and keeps having a small amount) after about 1-2 sets.

I am worried my exhaust manifold gaskets may be leaking water into the engine ignition - causing it to burn off as steam. I'm not sure if this even makes sense though - I am not too familiar with the indmar setup for manifold cooling.

Here are pictures of the two exhaust manifolds. The rust stains make me think there is a leak.

Any thoughts on either confirmation of the idea - or suggestions/comments on that it may not be that and other ideas.

Thanks,
Ben



Yes, it appears the manifold to riser gaskets are leaking badly, need replacing and can be found here, http://www.skidim.com/prodinfo.asp?number=OSC992-MK

snivesatgt
10-13-2008, 08:19 AM
...The oil cooler is the black metal cylinder near the hull fitting where raw water comes in and has two hoses connected to the transmission...

This obviously just cools the tranmission oil and not the engine oil, correct? Is there anything that cools the engine oil and does it make sense to get something aftermarket that does?

TMCNo1
10-13-2008, 10:29 AM
This obviously just cools the tranmission oil and not the engine oil, correct? Is there anything that cools the engine oil and does it make sense to get something aftermarket that does?

There is no reason to add a engine oil cooler, as these marine engine already run much cooler than the street versions due to the constant cool water flow and a lower degree thermostast that is factory installed..

flipper
10-13-2008, 10:34 AM
Is it white smoke, or steam that's coming out. Is it using oil? Have you checked the compression?

snivesatgt
10-13-2008, 04:21 PM
Hmmm - This may be a amatuar question, but how can I tell the difference between steam versus white smoke. It doesn't smell too potent. I don't notice any blue/black tint to the color so assumed water.

As my above statements suggests, I'm not to sure though - is there an easy way to quickly tell the difference?

It goes through a small amount of oil, but not tons. I have not performed a compression test - would this quickly rule out the chances of the white smoke being oil burning? Or is it usually blue enough to tell that it's oil versus water?

Thanks for all the responses - like all the ideas/suggestions - going to test them out next few days.

Ben

JimN
10-13-2008, 07:47 PM
It'll smell like burning oil if it was that and all you need to do to find out what that smells like is drive your car or truck and put a few drops on the exhaust manifold- you'll immediately smell it but if the white cloud doesn't have much odor, it's water.

flipper
10-13-2008, 08:05 PM
Also, if the white cloud trailer you for a little while, it's oil. It it disappears almost right behind the boat, it's steam.

JLeuck64
10-13-2008, 09:41 PM
Yup, I had to replace the riser gaskets on my little hot rod this summer too. They were just leaking a little bit outside leaving stains on the manifolds. Although not as bad as YOURS! Dude, you should swap yours out!!! Especially if you think they are leaking water into the exhaust.

I found exact replacements at my local NAPA. They have a marine catalog with all kinds of stuff for our boats in it. New gaskets ran about 7 or 8 bucks apiece as I recall...