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DeepFrz · 26-09-2013, 10:56

When was the last time the injectors were rebuilt/tested?

rlg · 26-09-2013, 11:18

Never by me and Ive had the boat since 2000

westwinds · 26-09-2013, 11:22

Quote:

Originally Posted by rlg

...
when I fill with coolant, some does leak out cap after engine is warm, then it stops. I may not be losing any coolant.

From my experience, the last thing I worked on is usually the problem. I just cant figure how the exhaust maniflold/coolant "tank" is causing the problem, maybe its not

Coolant gets hot so it expands and overflows a little. If you look at a coolant recovery tank on a car for instance, you will see a hot and cold mark on the tank. If you overfill above the mark, you will loose coolant on a car. Same for a boat. Overfill the coolant tank and you will loose coolant for sure.

If you are getting normal flow of raw water out the exhaust, the only think I can think of is the heat exchanger has a lot of scale, but then the temperature gauge would be high. If the thermostat is stuck in a slightly open position restricting flow on the engine side, then the temperature gauge would also show higher than normal temperature.

If there is a crack in the head from combustion changer to cooling passage, then maybe you could get what looks like steam in the coolant tank without elevated engine temperature. It looks like overheating because the exhaust in the coolant seems like steam and overheating. Pressure testing the engine cooling system; however, would usually detect this. To be sure, get a crack testing kit from an auto supply house which checks for carbon dioxide in the coolant tank. If you find carbon dioxide, you know you have a crack. Do you see any coolant in the oil? Sometimes it settles in the oil pan so you need to drain or maybe pump some oil out of the bottom of the oil pan with a hand transfer pump and see if there is any coolant. Depending on the type of detergent oil, you will also get an oil emulsion that looks milky.

Water getting into the combustion chamber can work its way past the piston rings into the oil so that's why you look for coolant in the oil pan. Be aware that antifreeze in the combustion chamber will form acid that attacks the bearings, so do not wait too long to check on coolant in the oil pan.

It might be you temperature gauge is not very sensitive. You could purchase something like this: General Tools IRT207 Heat Seeker 8:1 Mid-Range Infrared Thermometer. I just bought one from Amazon and like it for checking automatic transmission temperature after pulling a boat out of the water on a trailer. Do not want that temperature above 250 degrees Fahrenheit on an automatic transmission. The infrared thermometer could also be used to check for engine temperature.

Charlie · 26-09-2013, 11:22

Not sure that the injectors are the problem but you can get them tested for a pretty cheap price if you bring them into an injection shop.

rlg · 26-09-2013, 11:30

Heres a video of the smoke

westwinds · 26-09-2013, 11:30

Quote:

Originally Posted by Charlie

Not sure that the injectors are the problem but you can get them tested for a pretty cheap price if you bring them into an injection shop.

Good idea since bad injectors can cause severe cylinder wear and having the injectors checked would remove the item from consideration. I would have injectors checked every 1500 hours and rebuilt by the shop if needed.

rlg · 26-09-2013, 11:35

No coolant or water in oil.

Video is too large Im guessing

Snore · 26-09-2013, 11:35

Is the smoke at the dock or just under load?

If just under load could it be stress smoke from a dirty bottom or new/bigger prop?

Cheechako · 26-09-2013, 11:42

Quote:

Originally Posted by rlg

thanks for all the replies!

djmarchand, I will check the raw water intake and strainer but there seems to be the usual amount of water with exhaust, not excessively hot...
The temp gauge does not fluctuate once engine warms up.

Im not losing a lot of coolant, ran the motor for 40 hrs over a week from florida to NY without overheating or adding coolant, just some smoke, never used a lot of rpm..Never has the engine taken more than a cup or so of coolant.

when I fill with coolant, some does leak out cap after engine is warm, then it stops. I may not be losing any coolant.

From my experience, the last thing I worked on is usually the problem. I just cant figure how the exhaust maniflold/coolant "tank" is causing the problem, maybe its not

Maybe it is just injectors then. Is there a way for the raw water in the manifold to get into the exhaust at the head outlet area?

sailorboy1 · 26-09-2013, 11:48

Quote:

Originally Posted by rlg

Now she smokes white above 2000 rpm, only after fully warmed up.
If I keep revs lower, she'll smoke less, to nothing at 1200 or so.

It is a fuel and/or a fuel burn problem.

How old is the fuel?
Have you tried adding some fuel treatment to the tank?
Have to you run the engine under full load for for a period of time (15 minutes at least) and if so did the smoke go away?

If you have enough white smoke to be very noticeable and are not losing coolant, and since it doesn't smoke till the engine is warm, it probably isn't a fresh water system leak.

Since you say the seawater flow is "normal" it would seem unlikely that it is vaporizing seawater in the exhaust as the seawater flow rate is much more than what is needed to cool the engine. But since it only "smokes" once warmed up it could be a temperature related issue, but I wouldn't start there.

I would start with adding some fuel treatment and running the engine hard a while.

Jesse · 26-09-2013, 11:59

I had the same symptoms from my 4108. It was steam, forming in the exhaust system due to a reduced raw water flow. If there is no liquid water exiting with the exhaust there is a possibility you are cooking the inner lining of the exhaust hose. That will cause it to peel and plug the system at higher RPM's. It sounds to me like the new exhaust elbow isn't passing enough raw water to cool the exhaust properly.

westwinds · 26-09-2013, 12:22

Quote:

Originally Posted by Jesse

I had the same symptoms from my 4108. It was steam, forming in the exhaust system due to a reduced raw water flow. If there is no liquid water exiting with the exhaust there is a possibility you are cooking the inner lining of the exhaust hose. That will cause it to peel and plug the system at higher RPM's. It sounds to me like the new exhaust elbow isn't passing enough raw water to cool the exhaust properly.

No water in the oil so my thinking comes back to reduced raw water flow even though the OP states that raw water flow is normal. I missed that about a new exhaust elbow. Could there be a restriction at the raw water injection point? I think it quite possible "the new exhaust elbow isn't passing enough raw water to cool the exhaust properly".

rlg · 26-09-2013, 12:24

Quote:

Originally Posted by Jesse

I had the same symptoms from my 4108. It was steam, forming in the exhaust system due to a reduced raw water flow. If there is no liquid water exiting with the exhaust there is a possibility you are cooking the inner lining of the exhaust hose. That will cause it to peel and plug the system at higher RPM's. It sounds to me like the new exhaust elbow isn't passing enough raw water to cool the exhaust properly.

Im hoping its this but you can see the water coming out of the exhaust in the video...

Going to check the raw water strainer anyway.

I realize the injectors are overdue for service but I want to get to this water vapor smoke problem. Im pretty certain it isn't a fuel problem at this point.

thanks again for the input everybody

Jesse · 26-09-2013, 12:32

I just watched the video and there is plenty of water in the exhaust so that takes my idea out of play. It's past the recommended interval to service the injectors so doing that would be a positive and couldn't hurt anything. You could check the system with a I/R laser thermometer for excessive temps but your vapor trail does not look excessive, it's a common sight in Northern latitudes.