What do you think is going on here?

[Russell Clifton]

Last year the overheating safety device shut down my generator. After checking a few things, I removed the hose and determined the thru hull valve was plugged. Got out some wire and tried to open it up, then used my shop vac to blow air down thru the valve. Nothing worked so I re-plumbed to a unused thru hull and carried on. A few weeks later while in the engine room I opened the valve and water flowed freely thru it, so reconnected to it with no problems until last week. Same thing happened again a few days ago. The next day we cruised to another location and I checked the valve. It was once again working fine.

So it gets plugged up, can't free it up, cruise a day or so, and it is cleared out. Very strange. Almost like there is a vacuum created while under way that clears it out? What do you think?

 

[O C Diver]

Do you have a strainer screen on the outside of the hull and which way does it face?

Ted

 

[Russell Clifton]

Yes there is a slotted grill on the hull. No sure which way it is facing.

 

[RT Firefly]

Greetings,
Mr. RC. Thru-hull gnomes perhaps?

 

[C lectric]

Probably not this but I will mention it regardless.

Could be the screen has caught something that covers the intake from time to time.
A friend had this with one engine. It would have high temp problems periodically and drove him nuts. Finally in desperation since nothing worked he hired a diver. THe problem was a bag got caught in the leading edge of the grill and would sometimes block the grill.
Removed the bad, no more trouble..

Yours may not be the bag trick but if the T.Hull flows and then doesn't flow maybe something on the outside is blocking it.

I will venture that mussels or the like in the through hull may cause this. You might try rodding the T.hull out with a stick even though there will be lots of water.

A wire may be too small to be very effective.

 

[Ken E.]

Here's a WAG...something is trapped between the slotted grill and your genset sea strainer, maybe got there somehow through the slots in the grill. Its size and shape is such that periodically it will lodge and prevent flow, and then will dislodge and flow returns for a while. The grill doesn't allow you to ram a substantial rod down the hose and through the seacock to clear it. Maybe pull the grill at your next haulout and see what you find behind it

 

[PM]

It sounds to me like a leaf or seaweed got into the grill. Also sounds like you will need to send a diver down with a piece of wire with a hook bent into it.

pete