Water Pump Impeller Blues

[rickalan35]

Well, after having been spoiled for a number of years, the gremlins have resurfaced. Two week-ends ago, I ebulliently posted onto this site, my anchored location in a forested bay along the north shore of Big Rideau Lake. Life was great.

The next morning we had a leisurely breakfast and pulled anchor for Westport, eight miles further on and one lock away.

We arrived in Westport only to discover the place was full to overflowing and so we phoned Indian Lake Marina (three lakes further on) and made reservations for the night. We luckily managed to book ourselves the last remaining slip.

Four miles out of Westport in the middle of Upper Rideau Lake merrily on our way to Indian Lake, I glanced down at the starboard temperature gauge and almost fainted when I noticed it was up over 220.

I cut the throttle and shut down both motors.

I scrambled down into the aft cabin where the engines are located and sure enough it was full of smoke and the smell of burnt rubber. Aaaughhh.

Starboard water pump impeller had burned out.

Limped back home sixteen miles and one lock on one engine.

Next, this past week-end, with new water pump impellers installed in both engines we blithely sailed away and later on while cooking dinner, we managed to burn out the impeller in the Onan generator. Smoke. Thank goodness for that exhaust manifold temp gauge cut out.

Results 1: No, I had not ingested weeds. Turns out that the impeller on the starboard engine was at least four years old and should have been replaced as part of my seemingly fictional preventive maintenance program. My bad.

Result 2: The Onan generator water pump impeller was a different story. It had already been replaced this spring. When the yard opened up the pump today and pulled out the impeller, it looked good as new but it turns out that it had spun on itself. By this I mean that the metal core had come undone from the outer rubber flanged part. Thus the core was turning but the rubber section was sitting still, hence no cooling water to the engine.

Yes, I have learned my lesson and will be replacing impellers every second season.

Rick

[prowlersfish]

I got almost 5 years out of my last set ( I put the covers and insp them at least once a year) replaced them last year (still looked ok )and the new ones cracked in a year . you can win .

[captainmaniac]

Glad you managed to deal with the situations before they became critical, but you have also convinced me to get off my arse and deal with mine. I usually don't let things go 'un-done', but I have had the boat for 10 years and have NEVER changed impellers. As soon as its hauled out this year, new rubber is going in.

[rooferdave]

impellers? IMPELLERS???? uh oh

[k9th]

Glad you were able to limp back home and get her fixed. I know that feeling when you look at the temp gauge and it is pegged.....in the wrong direction.

New impellers are inexpensive and I keep two sets of spares onboard just for that reason.

[DaddysGirls]

WOW... Well, what happened to you is a lesson for me. As a new "bigger boat" owner I was un aware that I should check these. Sorry to hear about your misfortune but thanks for the tip.

[BobCT]

at least carror a spare on board with the tools to do it. If you're handy, this is an easy "roadside repair".

If you're not, at least you'll have the right part on board for someone else to help you.


Bob

[captainmaniac]

I know some people who religiously pull their impellers at the end of every season, inspect them, and store them in a container filled with (I think) mineral oil over the winter to reduce the amount of 'set' the veins take on.

[sehord]

I just changed both mine as a PM to prevent that from happening to me. Since they are a little Spendy, I just keep my old ones in a parts box on board, that way if I loose on while away I do have an emergeny spare to put in its place. Be carefull not to break the teeth on that little oblong grate when you pull the old one... that little gem runs over $70.00.... (i had a hired hand learn me that a few years ago...before I started doing it myself)

[Big D]

Hey, you guys are lucky, I have 2 on each engine to do all the time!! Maniac, may I suggest you replace them before launch next spring instead.

[davescarrs]

87 Trojan 10 Meter Int Crusader model 350 (454's) sherwood pump.

I seem to be running a little warmer on the starboard side, about 180 to 200 degrees, but the port side is running just below 180 degrees.

I changed the impellar and it may have helped a little. The impellar looked pretty good though. However, they were stuck in the bent position, but not torn up at all. I'll do thermostat next. Then I guess look at the heat exchanger etc

What should she be running at? 160 degrees at cruising? Or is 180 degress acceptable? 200 too much. i think there is a little more steam than I've noticed before too (now I'm making myself crazy with all of this). I'll be checking the intake and incoming water for restrictions too.

[ready123]

FYI putting in new thermostats (160 deg) dropped my temps from area of 180 to 160.

[sehord]

454 (350 HP) should have 160 thermostats in them and your temps should be about that. Check your h20 exhaust flow and see if it looks about the same on both engines, and for about $60.00 every boater should have a thermal temperature gun. (pick one up at your auto supply store) take it and look around each cylinder area each exhaust area and temp sending unit area and compare it to your other engine and gauges. it'll save a lot of time hunting blocked heat exchangers, blocked elbows, clogged oil coolers, barnacles on the pick ups....( lets see what other thousands of places have i had to hunt over the years!)

[ready123]

$30 gets you this:

http://www.horizonhobby.com/Products/De ... dID=PXTPE1

[prowlersfish]

Temp gun is a great thing to have but remember the out side of the engine will read lower then the inside due to heat loss , figure about 10 deg.