spring vapor lock?

[Scott Danforth]

The exhaust ports look rust free. The elbows have some buildup inside, but not messing with the mating surfaces.

post a pic of the mating surfaces. That may be the source of your hydrolocking

 

[ShoalSurvivor]

I see no rust inside. The mating surfaces are covered with the foil/lead gasket. They scrape off fine. There is no rust inside the ports.

 

[ShoalSurvivor]

And, I don’t know that it’s Hydrolocking. That was an early guess.

 

[ShoalSurvivor]

If you store outside try to support & water proof the cover & jack up bow with plug out

Yep - that was my gaff. Bow was up. Cover failed. plug was in.
I had it garaged since 2013. new car took its spot, out outside it went.
learning lessons, now.

 

[nola mike]

Lastly, after the engine is shut down, there is occasionally a sound of a small motor coming from the engine. I think It must be the fuel pump, but was unable to capture video or isolate sound. there is a hissing sound with it. I looked carefully for excess fuel. none. I will inspect the carb before restarting. my instinct was fuel pump - but please direct me. thanks.

Fuel pump should be off with the ignition off always.

 

[Lou C]

Your exhaust ports look OK to me, did you fog this engine before storage?
If not I wonder if all that moisture, slightly corroded the cyl walls in storage?

 

[nola mike]

And, I don’t know that it’s Hydrolocking. That was an early guess.

Sounds like it was. You still shouldn't have enough fuel in the cylinders to geyser out of the cylinders, no matter how much you pump the throttle. Don't know how much of that was mixed with water versus straight gas.

 

[nola mike]

.

Are procedures for post flood maintenance listed anywhere?

Haha, I can write a book on it at this point. Most things need to be done quickly, however I would for sure pull your drive, likely you have water in your bellows and the accompanying mess of that. Also, if youre starter, alternator, trim pump were submerged, there's a good chance of failure. Although likely less with fresh water submersion

 

[ShoalSurvivor]

Sounds like it was. You still shouldn't have enough fuel in the cylinders to geyser out of the cylinders, no matter how much you pump the throttle. Don't know how much of that was mixed with water versus straight gas.

It didn’t geyser, But we’re mincing words.
I don’t believe there was water in the cylinders. Only the exterior of the plugs had rust.

No leak from manifold.
I didn’t fog.

My challenge is that I have to take it back to the yard while I order new gaskets for the manifolds and lower unit.

I don’t want to leave the ports exposed … plugs are still in. Manifolds are off. Lower unit still on. Should I fog the port holes and tape them up while I’m waiting?

 

[nola mike]

It didn’t geyser, But we’re mincing words.
I don’t believe there was water in the cylinders. Only the exterior of the plugs had rust.

No, distinction is important. If the cylinders were filled with gas, that would indicate that your carb is overflowing and gas is causing the hydrolock.

No leak from manifold.
I didn’t fog.

My challenge is that I have to take it back to the yard while I order new gaskets for the manifolds and lower unit.

I don’t want to leave the ports exposed … plugs are still in. Manifolds are off. Lower unit still on. Should I fog the port holes and tape them up while I’m waiting?

Stuff a rag in them, tape, whatever. Wouldn't bother fogging. Take the lower off though, if the level was that high in the bilge your bellows are full of water, and you're looking at gimbal bearing/u-joint replacement at a minimum.

 

[Rick Stephens]

This is weird. The fuel pump potentially running is a big strange. I don't see signs of any water in the exhaust. And we would, when water is present in the combustion, it will quickly burn off carbon deposits in the exhaust. They all look perfect and not cleaned off.

 

[Lou C]

What did your spark plugs look like? Water would bleach them white and you might see some rust on the electrodes. It is possible for a hydrolock to happen because of a leaky carb float. I've never had it happen but certainly possible if the needle valve totally fails. If you've been running rich, they could be black. Another possibility is if someone wired up an electric pump with no safety circuit to cut the pump when the engine is not running.

 

[ShoalSurvivor]

No, distinction is important. If the cylinders were filled with gas, that would indicate that your carb is overflowing and gas is causing the hydrolock.

Agreed. and I now think the gas IS causing a hydrolock. I described a small motor and hissing sound that ran after the engine stopped. I suspect this was the fuel pump, filling the cylinder again, and causing another hydrolock. After that, As I mentioned, the starter engaged, but didn't budge the shaft/cylinders. But after a few tries, it did fire right up. I didn't have to remove plugs to clear the cylinder that time.

What did your spark plugs look like?

relatively clean, 1 was dripping with fuel.
note: when I cranked the engine without plugs, I did not see gushes of water or fuel. My battery cover was sitting next to the spark plugs hole and there was some fuel spray on it afterwards. It looked like fuel only, no water.

Once I put the plugs back in, it started right up.

the more I learn, the more I suspect the fuel pump is the culprit, and the rest of this is just cleanup from a bad outdoor storage cycle.

I will remove the lower unit and inspect. I ordered gaskets to reinstall.
I'm going to clean all the manifold matings today, and if clean, I will reinstall.

questions:
1) read a post about spraying motor oil into the cylinders through the spark plug holes and cranking. is this something I could or should do to prevent rust in the cylinders while im diagnosing/repairing? or do I need to wait until the manifold is back on? Is this precautionary or unnecessary if there's no water leaking into the engine?

2) Does the post shutdown "motor/hissing hissing" that I heard sound like a fuel pump or carb issue? How do I diagnose?

Thanks, everyone for your support!

 

[Rick Stephens]

First priority is to chase your fuel pump wiring. There should be no power to the pump unless one of two conditions exist:

1) The starter is cranking. During cranking the starter powers the Purple/Yellow wire which goes to the fuel pump.

2) The motor has built enough oil pressure to activate the oil pressure switch, which also powers same Purple/Yellow wire powering the pump.

Without either of those condition there should never be power to the fuel pump.

 

[ShoalSurvivor]

First priority is to chase your fuel pump wiring. There should be no power to the pump unless one of two conditions exist:

1) The starter is cranking. During cranking the starter powers the Purple/Yellow wire which goes to the fuel pump.

2) The motor has built enough oil pressure to activate the oil pressure switch, which also powers same Purple/Yellow wire powering the pump.

Without either of those condition there should never be power to the fuel pump.

Is there any other small motor/hissing sound that I could be mistaking for a fuel pump?

Would a bad oil pressure switch close the circuit, or leave it open? I will test to see if it's stuck closed?

 

[nola mike]

Is there any other small motor/hissing sound that I could be mistaking for a fuel pump?

Probably. Hard to say without hearing it. You need to actually go to the engine compartment and listen to where it's coming from

Would a bad oil pressure switch close the circuit, or leave it open? I will test to see if it's stuck closed?

It could do either, but unless you're either cranking the engine or the ignition is in the on position, the switch has no power going to it

 

[ShoalSurvivor]

It could do either, but unless you're either cranking the engine or the ignition is in the on position, the switch has no power going to it

The oil pressure switch leads test open (no conductivity) with no power. I didn't test the sender.

fyi, The motor/hissing sound (possibly fuel causing hydrolock) is intermittent. It only happened once after shut down. I cannot recreate to capture or identify, but my guess is that it was coming from the carb and it sounded like spraying.

Do I need to have the engine runable (with manifolds) before testing the fuel issue any further?

Now that I presume there no exhaust manifold leak, Should I do anything further to inspect/lube the cylinders, or just replace the plugs (because they are corroded on the exterior).

Also, I pulled the drive and it's clean and lubed. no sign of any water. Gimble looks happy. I will change the water pump and reinstall.

 

[Rick Stephens]

What you might do is connect power to the purple/yellow, which will spin up the fuel pump, and then look in the carburetor without the engine running and see if there is any fuel leaking down the intake while it is just sitting there without the engine turning over.

 

[ShoalSurvivor]

What you might do is connect power to the purple/yellow, which will spin up the fuel pump, and then look in the carburetor without the engine running and see if there is any fuel leaking down the intake while it is just sitting there without the engine turning over.

Thanks, Rick. that makes sense.

I had to return her to the yard today or my neighbors get fussy.

I will check this in a few days.

 

[ShoalSurvivor]

one year later...

I apparently didn't get around to finishing the job. Where I left off was diagnosing a starting/fuel/carb issue.

Upon inspecting the carb, I found corrosion. I have never maintained it, but I'm certain this was "clean" when I put it away. Despite surface corrosion, the parts that move with the throttle are moving, but the choke flap is not. Should I be able to flip that open/closed with my finger?

I'm not experienced with carbs, but my instinct says this needs rebuilding.

Comments welcomed. thanks.