Water pouring out of exhaust!

[Project_Mayhem]

In the never ending saga of issues with this boat I finally got my inboard working tonight. I was very happy to report that it fired up on the first crank after rebuilding the carb. The one unusual thing was the shear amount of water that was coming out of exhaust. It was comparable to a garden hose but a bit faster. There was a significant amount of smoke (or possibly steam) as well. It's a two stroke OMC saildrive. The idle speed didn't seem unusually high. It's been over a year since the motor has been ran for more than a minute or two

Full disclosure: As I was going through the engine I found that the water intake valve was only opening part way. The outlet of that valve was about 40% blocked. I believe the ID of that portion is 5/16". So I installed a new valve using standard brass plumbing parts. The original valve is no longer being manufactured but I can try reinstalling the one I removed. The amount of water still seems excessive.

If anyone has some insight I would greatly appreciate it

 

[JohnShannon]

So you put a bigger valve on it and you are getting more flow. Wasn't that the objective? I predict the board will have lots of issues with "brass plumbing parts" . Consensus is bronze not brass. If you want to cheap(ish) out there is Marelon which is glass filled nylon. I think maybe there are also issues with thread compatibility between plumbing parts and marine parts.

Maine sail has written about this, search around site for it. it is the closest thing you will get to the voice of god.

 

[Capt jgw]

I can't see how a malfunction could give you more water. The pump is going to put out whatever it's supposed to at any given speed. If it's less, that's a problem. Perhaps the old valve was partially blocked because the PO only had it partially open? As for the plumbing fittings, are you in fresh or salt water? Brass would be ok for a while in fresh, but will corrode pretty fast in salt. Marelon has some advantages. Usually cheaper than bronze, not quite as strong but no corrosion problems. If you go that way make sure the fittings are black. There are some white ones out there, they're not the real deal. Had one break off on my hand once, that got exciting.

 

[jssailem]

As I was going through the engine I found that the water intake valve was only opening part way. The outlet of that valve was about 40% blocked.

First. Water out the exhaust is your friend. think of it like air through your car radiator. It the radiator fins are blocked with bugs the engine over heats. So cooling water flow is good.
We had a good discussion about corrosion this spring. Brass corrodes quicker than bronze. You may be switching out you brass fittings much sooner. Note your in fresh water not salt water. MaineSail’s web site has pictures of what happens to brass on a boat. Not pretty.

 

[capta]

Two things. Never use brass. It will corrode away very quickly. Use marine bronze or SS.
The other is that your engine is designed ti run at around 180 degrees F. Too low and all the metal parts haven't expanded to their proper point. Have you ever seen semi tractors with cloth cover over the radiator? That's exactly why. They can regulate the amount of air cooling the circulation system.
When I've taken vessels from Frisco to Ak. I've often closed the intake seacock partially to keep the engine at the correct operating temp. It sounds like the PO had figured this out.

 

[Project_Mayhem]

Noted on the brass vs bronze. I'll take a look at the old fitting to see if it's tapered. The handle on the old valve broke a long time ago but I was able to open/close it with some vice grips. It only opened partway. The output from the valve to the exhaust riser is connected by a hose that I believe is 5/16 or 3/8". Here's a few videos to give you an idea of the amount of water coming out. Seems excessive to me for what's essentially an outboard engine mounted on on an inboard lower unit
2020-09-29 23.40.12.mov
2020-09-29 23.39.24.mov
2020-09-29 23.29.09.mov

I assume the large amount of smoke is due to the fact that the engine isn't warmed up? It was idling for 5-10 mins before the video was taken. Of course the large amount of water is keeping the temps down. Is some of this likely steam as well?

 

[jssailem]

You should see the water passing out of my boat at cruise.

Not seeing an issue. Note the engine will be hotter at the cylinders. My cylinder exhaust temp at the exhaust manifold runs about 190. The coolant temp runs about 155 which is displayed on the engine console.

Perhaps you are just used to seeing the 40% restricted flow.

 

[Project_Mayhem]

This is actually the first time I've ever seen it running on the water. I assume you have a diesel and its operating temperature would be different?

 

[jssailem]

Correct assumption. But pumps are pumps and the goal of water is to provide a cooling system to the boat. When the water does not flow through the system the cooling is
compromised. The size of the provided the water the pump and the size of the internal system determine the volume of water. Were there issues with the engine before you began to work in it?

 

[twalker H260]

All 2 stroke motors tend to smoke to greater or lessor degrees depending on the oil mix ratio and the type of oil mixed with the gas. 40 or 50 to 1 ratios smoke more than engines that call for 100 to 1. Be aware that many oils are designed for specific types of stroke motor - marine, motorbike, chainsaws etc.

 

[Project_Mayhem]

Correct assumption. But pumps are pumps and the goal of water is to provide a cooling system to the boat. When the water does not flow through the system the cooling is
compromised. The size of the provided the water the pump and the size of the internal system determine the volume of water. Were there issues with the engine before you began to work in it?

PO ran the engine on the hard for longer than it shouldve been when he showed it to me. It had been a few years since it was replaced as well. Started replacing pump, accidentally dropped pin into lower leg, wouldnt shift into reverse, installed outboard. Prior to lauching this year I inspected inside the leg for pin, none found, put engine back together, shifted fine but wouldnt run for more than a min, rebuilt carb, fired right up and here we are.

All 2 stroke motors tend to smoke to greater or lessor degrees depending on the oil mix ratio and the type of oil mixed with the gas. 40 or 50 to 1 ratios smoke more than engines that call for 100 to 1. Be aware that many oils are designed for specific types of stroke motor - marine, motorbike, chainsaws etc.

Outboard and inboard are drawing fuel from the same tank. 1996 outboard really only smokes when cold and at low speeds. Two stroke marine oil is TC-W3 certified