White Vapour / from Exhaust

[Mpeters]

My raw water impeller went last fall and I got my boat hot...gauge went to 200.. I immediately shut down, but It did smell a little like melted rubber or melted Fiberglas ... I limped back to the dock making sure not to get it back up to 200 .. I changed the impeller and now it runs 160 to 180... My problem is since then I have a lot of white smoke or steam coming from the back of the boat .. I never noticed it before but it may have been there... I might just be hyper sensitive to it now since then... Any one else see this in their boat?? ( 2001 sun setter VLX)

[Stevo]

Are you sure your boat isn't a Mastercraft?

sorry, i have nothing here

[teamerickson]

Are you sure your boat isn't a Mastercraft?

sorry, i have nothing here

Not helpful, but hilarious!!!

[REHinH20]

I have steam pretty regularly, it's common since the coolant (water) is expelled through the exhaust. I wouldn't consider 200 to be excessively high, and probably the rubber smell you noticed was actually the chewed up and melted impeller.

[t a]

I never notice it on mine but seems common on all the new boats I've been on

[saxton15]

Never noticed any steam on my boat, and I'm running the standard flappers.

[Stevo]

Yeah it's probably just Doc's boat.

[Mpeters]

Thanks for the feedback ( even Stevo for the comic relief)

[Lance B. Johnson]

i get small amounts of steam hovering around the swim step. Nothing to worry about, water is used to cool the exhaust. The 6.0 also has a small line that discharges in the transom that expels really hot water....I haven't traced it yet to find out what it is but its a nice feature to wet your wipe down towel if you need to.

There was some discussion around the steam being caused by rich fuel mixtures. I don't believe this is the case and its far more likely that it comes from the fact that water is used to cool the exhaust system.

Edited May 20, 2015 by Lance B. Johnson

[Steve B.]

First, check to make sure there is nothing impeding the flow of water from the pump into the engine. Old impeller pieces get stuck on the incoming side to the transmission cooler. Take off the hose going into and out of the tranny cooler and clean out.

After you are sure it's clear, start it up, with water, in the driveway or wherever. Make sure water is coming out both exhausts.

After that, let us know.

Steve B.

[GreenMan]

There is always some steam in the exhausts. Sometimes you will just notice it more.

If there was any damage that matters from the overheat, the most likely symptom would be water in the engine oil. Just make sure the oil on the dip stick looks nice and clean and not milky.

If it was from over-fuelling / too rich, the vapour would be black(ish).

[Mpeters]

Thanks GreenMan .. Ive been checking the oil quite regualarly to see if I cracked the head or burnt up a seal but it looks good.. Ive also had it in to the dealer.

I dont know how to upload vids or I would put it on ... Just seems like excessive steam.. Thanks for the input

[jrvs23]

Is it the first time running it for the season? If so it may just be a little excess fogging oil burning off. Get it on the water with the swim platform on and you won't notice it anymore!

[justgary]

It is also related to the water and air temperatures and even humidity, so maybe you are noticing it more because of that (plus you are watching for it now).

You had to be here to fully get the Mastercraft joke. It's buried deeply in the Pork Butts, etc. thread in the Off-Topic section. Read it tonight and give us a full report by tomorrow morning.

[Mpeters]

Hahaha.. Will do

[Kalamazoo]

It's typically cold in Canada. what you see is possibly due to the air temperature and will disappear magically in the summer.

[Woodski]

@Mpeters: I would suggest a leak down test to verify the head gaskets are still sound and piece of mind. Assuming the impeller incident was the last run on the boat prior to now observing excessive steam from the exhaust, and the boat has not run fine in between, a bad head gasket or combustion leak in to the exhaust will create additional steam. If the water level dropped below or there was no water on the temperature sensor when you limped back to the dock, you will not know how hot the engine actually got. It is typical for an overheated engine when losing water to register a lower temperature at the gauge when there is no water / coolant in the system and the engine is actually much hotter than the gauge reads. A key thing to check, did you burn any of the paint off the exhaust manifolds, engine components as that will be a good indicator of excessive heat. If you smelled burned rubber and fiberglass, I would do a thorough examination of the exhaust system as the pipes might now be quite brittle or have internal parts broken off.

[Lance B. Johnson]

Good info Woodski. I have only one thing to add.

Keep in mind that Leakdown or compression tests will not always reveal blown head gaskets...only in more extreme cases. Cylinder pressures are just so much higher under running conditions that we can't mimic that in a test.

[Brodie]

I too get a lot of white vapour. It doesn't smell like exhaust fumes, so I am hoping that it isn't, especially when I am surfing.