Burned up new raw water impeller

[jpstevens]

I like "Speed Seal" and a little lubricant at start up.

[Squanderbucks]

Doesn’t matter if strainer is above or below waterline. This only matter if you want the strainer to self fill when the top is open. These pumps will self prime and fill the strainer up to about 10 feet of height. Most boats are a foot or two at most.
If hoses are open on both ends it will pump. There are a number of more rare or unusual things like not fully sealing the gasket (letting sealer get into the faceplate screw holes and not cleaning out - preventing screws to fully reseat) or excessively worn cams or faceplates. These pumps are normally bullit proof. Usually operator error with the shutoff valve.
All these things such as profiling strainer are nice but should not be the cause of pump not pumping.

[basssears]

+1 for a bunch of glycerine lube on impeller after installing (gooey mess if you do before installing )... protects on startup and helps it prime.

-- Bass

[Rough Magic]

Second vote for Globe run dry impellers. But still use glycerin lube on the impellers.

[KWISPEL]

After hulling the boat out the water or replacing the pomp or impellor is there aire in the system. By somme boats wil the air stay if you give not a few seconds a higher RPM to bleed the air out the system.

[kmacdonald]

Rubber impeller pumps are self priming. There is no need to fill strainers or anything else for that matter. Just open the sea cock and start the motor. Fin position doesn't matter either, it will set to proper position when started.

[rocnrichy]

Thanks again for all the tips. Went over to the boat this morning and put the new impeller in, lubed it with dish washing liquid, and fired her up, and watched it pump water like new. Thinking there was a bubble in the system even though the strainer was filled. At any rate monitoring the water discharge will be a part of the engine starting procedure.

[JOHNMARDALL]

Very sorry to hear about this problem, and sadly,my comments are going to make it worse. If the engine ran long enough to make the dry impeller pump that hot, then you had red hot (500 -800 F) exhaust gas passing through the exhaust system for some time, and it's a safe bet that the exhaust system is damaged. There may be no visible damage, but the exhaust hoses, waterlock, etc are almost certainly burned on the insides and if so, must be replaced. Taking a chance on this puts everyone on the boat at risk, especially crew asleep at night when if an exhaust leak opens up, smoke may not be visible until it's too late.

As you've already checked that the sea cock is open and the scoop not blocked, my guess is that the pump is not priming itself, either because the O ring on the impeller pump face place and/or on the top of the strainer is not sealing, or the geometry of the raw water intake system is making too much head for the pump to pull when it's dry. What works for me is to pack the body of the pump with non-grit/non-pumice gel hand cleaner once the new impeller is in place, and also use that hand cleaner as a lubricant on the O rings, which will distort if they're dry when you tighten down on them. That will keep the pump pulling until water gets to it.
Lastly, the best $100 you will ever spend is for an exhaust gas temperature sensor and alarm, which straps on to the exhaust hose just below the mixing elbow and will sound off as soon as the exhaust temperature rises in a no-water- flow situation. If you shut down immediately, the exhaust system will be saved.

I hope this helps -please send me an email if you need more information

Good luck, hang in there
John Mardall
Vetus Maxwell Group

[Olddan1943]

Originally Posted by JOHNMARDALL

-----

Lastly, the best $100 you will ever spend is for an exhaust gas temperature sensor and alarm, which straps on to the exhaust hose just below the mixing elbow and will sound off as soon as the exhaust temperature rises in a no-water- flow situation. If you shut down immediately, the exhaust system will be saved.

I hope this helps -please send me an email if you need more information

Good luck, hang in there
John Mardall
Vetus Maxwell Group

John, please tell us the specifics for the exhaust gas temperature sensor and alarm.... ie, make, model and price.
Thanks, Dan.

[Madehn]

raw water failure alarm $79 from Borel manuffacturing-- can also get an optional remote alarm to go with it for additional 28 bucks easy to put on - easy to wire

[thunderhoof]

The Volvo Penta (and clone) impellers come with glycerine as a lubricant. As this is water soluble this cannot last more than a few minutes once the pump is primed. I guess this does the job. Why not supply petroleum jelly or something that would last a little longer?

[Olddan1943]

Originally Posted by Madehn

raw water failure alarm $79 from Borel manuffacturing-- can also get an optional remote alarm to go with it for additional 28 bucks easy to put on - easy to wire

Madehn, thanks for the information. I did a search and came up with the following URL

Wet Exhaust Temperature Alarm by Borel Manufacturing Inc.

Great insurance!! I shall call them tomorrow. I am going to assume they include calibration instructions. Just straps around the muffler ???

It says, the installation requires a 2 inch hole for the remote. Now, where did I put my box of 2 inch holes. SMIRK

Currently, I do not have any alarm on my generator. Why you might ask? I have been told repeatedly, the generator will protect itself. Yea, shuts down after the impeller comes apart.

[Steadman Uhlich]

Originally Posted by thunderhoof

The Volvo Penta (and clone) impellers come with glycerine as a lubricant. As this is water soluble this cannot last more than a few minutes once the pump is primed. I guess this does the job. Why not supply petroleum jelly or something that would last a little longer?

Water soluble is recommended.
Don't use a lubricant that may adversely affect the "rubber" or neoprene impeller. If you are unsure, contact the impeller manufacturer, as opinions among sailors may be mistaken.

How long should the lubricant last on the impeller? Seconds.
The cheap KY Jelly or other glycerin based lubricant only needs to last until the pump is pushing water through itself, which should happen in a few seconds.

If you don't use the KY Jelly (or similar) glycerin lubricant, liquid dish soap would work.

[a64pilot]

Originally Posted by thunderhoof

The Volvo Penta (and clone) impellers come with glycerine as a lubricant. As this is water soluble this cannot last more than a few minutes once the pump is primed. I guess this does the job. Why not supply petroleum jelly or something that would last a little longer?

Petroleum jelly dissolves some rubber and could possibly lead to some blockages further in the system as it isn’t water soluble.
In truth you really don’t need any lube, cause after the first start, where is the lube then? Some will say after first start there is water in the pump, and there should be.
If you have no lube and want something, then KY jelly or plain ole dishwashing liquid works fine, both are water soluble.
I put a tie wrap on the impeller and squeeze it smaller to make installation easier, The tie wrap has to be slid off during install, but does make it easier.
Don’t worry too much about getting vanes backwards, it happens all the time, I’m sure you have seen a Diesel turn backwards sometimes on shutdown, well when it does that, it turns the vanes backwards and it doesn’t seem to hurt them.

[basssears]

Originally Posted by Olddan1943

Madehn, thanks for the information. I did a search and came up with the following URL

Wet Exhaust Temperature Alarm by Borel Manufacturing Inc.

Great insurance!! I shall call them tomorrow. I am going to assume they include calibration instructions. Just straps around the muffler ???

It says, the installation requires a 2 inch hole for the remote. Now, where did I put my box of 2 inch holes. SMIRK

Currently, I do not have any alarm on my generator. Why you might ask? I have been told repeatedly, the generator will protect itself. Yea, shuts down after the impeller comes apart.

A good early warning system can be built with these guy's temp sensors:
http://enginewatchdog.com

I now have one dual and one single unit onboard and am very happy with them... easy install, warns me of heat whether water is going past my coolant temp sensor or not, alarms, great piece of mind. Blog posts of mine on subject:
http://sailing.pictureofnectar.com/some-like-it-hot-and-other-mods
http://sailing.pictureofnectar.com/spring-work-all-about-the-power

-- Bass