White smoke or steam along with running hot.

[cfergu22]

Last season I was having problems with some smoke leaking out of the engine around the manifold. I took the manifold off and had to replace one of the studs. I put a new gasket on the manifold and it stopped that problem.

I'm not sure when the exhaust got this bad but this is what it looks like now.

http://m.youtube.com/watch?v=22fQijCxYXA&feature=plcp

[YOUTUBE]22fQijCxYXA[/YOUTUBE]

This is with the engine running in forward at about 3/4 power. It will reach temperatures up to 200 and above if I run it like this for longer than 3 or 4 minutes. I removed the thermostat and did an acid flush to try to increase the
Water flow, no help. I left the thermostat off and closed the bypass to force all the water through the engine, that didn't help. The impeller is new as of last fall. I cleaned the water lift muffler no help. The water output seems a little low to me, here it is at idle.

http://m.youtube.com/watch?v=OGCRIlBkIck

[YOUTUBE]OGCRIlBkIck[/YOUTUBE]

Oil pressure and level remain fine since last change around 3 engine hours ago.

In the first video You can hear a fast knocking or tapping coming from the engine. I think that is a relatively new sound. It only happens when the engine is under load at high rpms. I don't know if the sound and smoke are related. The engine smokes all the time, even at idle. The faster the rpm, the more smoke.

My first question is can anyone confirm, is this steam or smoke? I want to know what troubleshooting road to go down.

Does anyone think the noise and smoke/steam might be related?

Does anyone think the water output is low?

Does anyone have a good idea of what to check next?

Thank you very much, this sight has been a huge help in the past.

[Al Schober]

In the first video, I see no water. In the second, some water but not much. I think you have a blockage that you have to clear. Get this engine running cool, then we'll worry about the rest.
First guess for blockage would be the outlet of the exhaust manifold - but that's just a guess. Perhaps a systematic approach?? Disconnect stuff and blow through each piece - if it's not clear, you'll know it.
Is this a raw water engine, or is there a heat exchanger to worry about too?

[ndutton]

That looks like steam to me and the water volume looks marginal at best. I agree an obstruction is likely. The cutesy machined elbows are the first places to check. You'll find them at the water pump discharge, the manifold inlet and outlet.

You may be headed for sideplate removal and inspection of the water jacket and sideplate diverter. Elbows first though.

[cfergu22]

Al, it's a raw water cooled engine. Good idea with the blowing through lines. I'll try to work backwards through the system tomorrow afternoon and see if I can find a blockage. Thanks.

[Mo]

Here we go

It looks to be steam because it disipates shorly after exiting the boat.

Several suggestions...in this order. Leave the T stat out and by valve open 1/2 for now...not closed.

-do a compression check using a gauge...
-pull the plugs out after it has run like in the video, take a pic of them and post it...plugs say allot.
-check to ensure raw water intake valve is fully open.
-check there is not a restriction from outside the boat...a blockage of the intake by sea life etc.
-remove the hose from the pump where it goes to the engine...between the pump and the engine...see if there is debris caught up in the elbow there. Continue as far as you can and check all elbows for debris clogging them. Happens frequently.
-remove the hose of the rear of the manifold and see if you have a blockage / restriction there ...happens frequently as well. If the boat was winterized in cold climate pressure test the manifold while you are at it...a crack would put steam in the exhaust.

The ticking sounds like a valve...but that needs to be hunted down via listening closely with a rubber hose to your ear...or Dave's long screw driver. We can sort through that as we go along....I hear it and it's not a knock...so that's good.

[edwardc]

I agree with the guys. It's steam.

You're just not getting enough water flow through.

Mo's suggestion of something (sea life or other) obstructing the raw water intake is my number one vote. Especially if you have one of the "external grate" pickups that were common in that era.

You can easily test for that without getting in the water by disconnecting the pump from the intake seacock and sticking it in a 5 gal bucket of saltwater sitting on the cabin sole. If everything else is functioning , you should empty the bucket quickly, and see much better water flow in the exhaust as long as the bucket lasts.

I would try this first, as running the impeller starved for water probably isn't doing it any good.

[cfergu22]

I think the overheating problem might be resolved for now. Last night I systematically took apart all the cooling hoses and tested them for output at each point. Each time I removed a hose I would run a screw driver through the inside of the elbow to try to see if there was a blockage.

I started from the pump, I removed the output hose from it and ran a temporary hose to a bucket. It pumped out 3+ Gallons in a minute at an estimated 1000 rmp. That's supposed to be normal as I understand it.

I replaced that then went to the output of the Thermostat housing and ran that into a bucket. Same thing, 3 Gallons a minute.

Then I went to the output of the manifold and ran that into a bucket and got the same thing. 3 Gallons a minute.

Then I hung a bucket off the back of the boat to catch the exhaust water. I got the same thing, 3 Gallons in a minute.

I guess any blockage that was in there was removed by me taking the hoses off and running a screw driver through the fittings. I did notice that the initial half gallon or so of water that came out of each area was filled with black soot. Maybe this was stuff that was loosened up with the acid flush 2 days ago that was still caught in the engine yesterday. Anyway, Here is what the output looked like after all the test were complete. This is running under load at about 3/4ths power.

http://www.youtube.com/watch?v=fY-Psocv89w

[YOUTUBE]fY-Psocv89w[/YOUTUBE]

Does that look normal to everyone? After 20 minutes of running the engine temp was normal and there wasn't any steam, It seems like the problem is fixed for now. I'm going to take the boat out and run the engine more this weekend and make sure the overheating problem is over.

I'm going to start a new thread about the engine noise.

[Kelly]

That does look a lot better but please be leery of problems "just going away" without a real fix behind the improvement.

In any case, it does sound like you're ready for some on-water testing.

[JOHN COOKSON]

My $0.02 Worth

I guess any blockage that was in there was removed by me taking the hoses off and running a screw driver through the fittings. I did notice that the initial half gallon or so of water that came out of each area was filled with black soot. Maybe this was stuff that was loosened up with the acid flush 2 days ago that was still caught in the engine yesterday.

Maybe the cooling system was so blocked with "black soot" that was picked up somewhere, that the flow and cooling was compromised?

TRUE GRIT

[edwardc]

Good flow and no steam, looks like a winner for now.

But do heed Kelly's warning about problems that go away by themselves.

They usually come back by themselves!

[dthibaul]

That's exactly what my raw water exhaust outflow looks like.

Don