Replacing impeller when stopcock seized

[Pete7]

Originally Posted by HopCar

Don’t forget the problem could be caused by a blockage somewhere in the intake system.

This ^^^^^^

[kmacdonald]

Originally Posted by boatpoker

Didn't your surveyor check all your seacocks ?

Again..... this forum needs a "LIKE" button.

[Time2Go]

Originally Posted by Sustainablecam

Thanks Paul,
I *think* that the water inlet is in the sail drive leg so I don't think that would be an option at this stage. My mate was suggesting that next time I have it out of the water that I redirect the water inlet to a new or existing through hull fitting and make sure that it has a good strainer on it. Certainly considering doing that but again that would have to wait until the next time she comes out of the drink.

Cheers.

Water intake on sail drives just plain suck
We sucked in a plastic bag and it was a nightmare
fishing out all the bits and pieces
First thought it was the impeller which would have been easy but no joy there
Cheers
Neil

[pcmm]

Originally Posted by Sustainablecam

Hi folks,
It's time for the first service for my recently acquired Farr Phase IV with a Volvo Penta D1-30 inboard.

I want to change the impeller but have discovered that the stopcock for the seawater inlet in behind the engine is seized. I don't know how seized as I'm wary of trying to force it to find out.

My options would seem to be to pull it out of the water to replace the stopcock (really don't want to do as I just had it out when I purchased it) OR to try to loosen up and un-seize the stopcock somehow OR to crimp off the line somehow OR to just pull the impeller plate off and swap it out and stick the new plate on and hope that I don't have too much water run into the engine bay water sump.

Suggestions please?
Thanks in advance!

When you launched were all the seacocks not closed? How long ago did you launch? All the marina's I've dealt with have asked for seacocks to be closed at launch, then you hop aboard while still in the slings and open them and check for leaks....you're going to want to replace that seacock sooner than later. If its seized, then corrosion is definitely a factor in the condition of the seacock. I wouldn't be comfortable with stuck valves , but then I do tend to close all seacocks that are not in use (including the engine at the end of the day!)

[-bliss-]

Don’t you have a raw water- strainer? If you do, it’s most likely mounted above waterline. Removing the top cap lets air into the system and stops the siphoning. Then you’re good to go! (In the strainer you might as well find what’s been causing the problem..) After assembling the new impeller, it’s good habit to add some fresh water in the strainer, just to make sure the water pump is filled with water, just to make life easier for the new impeller the first seconds of its life.

Regarding seized valves: WD40 is your friend. Spray gently, let the oil penetrate for a while, repeat as needed and start moving the handle gently. Be patient. In a day or two you’ll be able to work them flawlessly.
Good luck!
-kjetil-

[mikecambrai]

Firstly you cannot put to sea if you cannot get at the Jabsco impeller. If anything is going to fail it is that impeller. I really don't know why they are fitted. There must be more reliable alternatives. In the old Perkins S6M's they had 2 fibre gears as you have in engine oil pumps and they were totally reliable.
Remove the pipe feeding the pump as has been suggested and check the flow for any obstruction. Then plug it and examine the Impeller. Carry the plug with you when you go out because at least you will have practised what to do safely if the impeller does give out.
But it is a fundamental of boats that the hull integrity is sacrosanct. All sea cocks must be in working order, the stern glands must be checked for any leakage and adjusted as required, and all filters regularly cleaned. If you leave the boat go 'dead ship' and turn off all seacocks. You will always know that they are working and you can sleep peacefully in your bed knowing that the boat cannot sink.

[Shrew]

The seacock is a critical piece of safety equipment. It is not a tool to make maintenance easier. There could be significant growth possibly restraining water flow and preventing the valve from being shut.

The prudent action would be to haul the boat, inspect the water intake system, replace the seacock, replace the impeller. Relaunch.

[sailah]

Also check your heat exchanger. My engine was running a bit warm and the raw water inlet on the HX was necked down from a 25mm hole to about 1/4 of that.

Just salt that had precipitated out. Cleaned out HX back to normal.

I'd go with: pull a hose from somewhere and be sure to have 2 methods of plugging said hose in your lap before you do. The cover plate (at least mine does) has a thin gasket and I can't imagine trying to fit this gasket in place, plus tiny screws with sea water gushing in.

My seacocks have 1/8" NPT threads in the body. Every spring I attach a grease gun whip hose to these threads and work the handle while pumping a bit of grease in there. I ensure all seacocks are operational before launching.

[Cadence]

Originally Posted by Paul L

Or jump in the water and stick a bung plug into the inlet.

A good idea for either problem. Fooling with the seacock or replacing the impeller. If replacing the impeller, at this time is not absolutely necessary.I would be more concerned with an nonfunctional seacock.

[Seas The Moment]

Google Seabung Youtube. It is rather costly (USD $75 for two and a plug). You insert through the open stop cock, plunder is held against the outer hull, you unscrew bad SC, screw on good one.

[HopCar]

I don’t think a Seabung will work if the pick up is in a Saildrive leg. They work great with regular mushroom head thru-hulls.

[t588143]

Redirecting the cooling water flow away from the saildrive is not such a good idea as this cooling water is also used for cooling of the saildrive itself. Reduced cooling water flow is most often caused by pieces of previous impellers getting trapped in the heat exchanger and blocking the flow of water to the exchanger tube. Sorry to say but the best option is to take the boat out and clean the entire system.

[01kiwijohn]

Unless you're planning an offshore trip, just squeeze (squeeze, not crush)the inlet hose with a pair of vice grips and replace the impeller.
I'd also carry one of these little gadgets, just in case.
Seabung - MyBoatsGear.com
Replace the seacock at next haul, or use a grid if there's on available.

[basssears]

Originally Posted by sailah

The cover plate (at least mine does) has a thin gasket and I can't imagine trying to fit this gasket in place, plus tiny screws with sea water gushing in.

With water still coming in the intake hose I envision salt water spraying all over the engine too while you're trying to fit the cover... not good.

[svJasmine]

what I would do is:

Remove the intake hose to the engine and have a short bit of cheap hose handy and a proper sized double hose barb. Quickly stick the hose in the hose barb that already has the other hose on it. Tie that hose above the waterline somewhere. take a sponge and wipe up the 2 cups of water that spilled.

replace the impellor and reassemble. wipe up the 2 cups a second time.

I have replaced shafts while my boat is in the water, and this would be easier.

Rich