Recommisioning boat-impeller tip

[LarryandSusanMacDonald]

Friday, a friend of mine here in the yard told me he was de-winterizing his boat and couldn't get any water out the exhaust from his generator.

Asked me what to check first - and I said 'probably the impeller.'

The head mechanic at the yard was nearby so I asked him. He said a lot of times the impeller blades simply stiffen up and don't conform to the pump - and thus just spin without pumping. He said the first thing to try is a heat gun or a hair dryer on the body of the pump. He said that usually softens them up and they spring right back into place.

It worked! I had never heard of doing that so though I would pass it on to the net - for you guys who are busy re-commissioning your boats for the spring.

[FarCry]

Nifty trick thanks for passing it on. For the amount of time it would take to do that I would probably just put in a new impeller. Using heat for a diagnostic tool makes sense though.

Don't most people who haul their boats during the winter replace the impeller as part of re-commissioning in the spring?

[LarryandSusanMacDonald]

Nifty trick thanks for passing it on. For the amount of time it would take to do that I would probably just put in a new impeller. Using heat for a diagnostic tool makes sense though.

Don't most people who haul their boats during the winter replace the impeller as part of re-commissioning in the spring?

Some do, some don't. The axiom "If it ain't broke, don't fix it." may hold some sway here.

If you can change your impeller faster than you can heat up the housing, more power to you. For many of us, just getting to the cussed thing is a challenge. A friend of mine, currently cruising in the Bahamas, e-mailed me for advice on changing his on his Yanmar. I put it to our expert mechanics, one of whom had worked on his boat - he said you had to remove an engine shoe (foot? what ever you call them thar thangs) to get to the back of it - or remove the entire pump. Fahgedaboudit! On my previous engine - a Perkins 4-108 we dubbed dieselbub - I changed the impeller once in about six years. I inspected it frequently, well, once a year or so, but didn't change it if it looked okay.

In any case, I'm not a mechanic. Engines have been known to cringe and back away when I approach with so much as a screwdriver (or a Bloody Mary). SO take my personal advice with a grain, nay, a block of salt. But when I relay info from the pro's, well, listen, I have great respect for these guys.

[FarCry]

I may be fortunate in having good access to the water pump bolts on my Yanmar. Having never actually tried to heat the housing with a hair dryer on the body of the pump housing, I assume it takes a while. Heat gun would be much faster. Hopefully I will never need to find out.

[T34C]

I gotta agree with Farcry- if the pump isn't moving water then its time to change the impeller. If you heat it and it starts moving some water you still don't know if all the blades are intact. If it takes a set in one direction, it likely isn't going to be working at 100%.

BTW- My yard, like many has a fixed rate for a lot of work, ie... there is a fixed price for impeller replacement. If it is that hard to get to, let the pros do it. Their price isn't adjusted because yours is hard to get to.

[petegingras]

impellers, reminds me of a certain necessary item on the fairer sex. I replace them once every year to 18 months, both the engine and the generator. Then i take the old one rub it with olive oil and bolt in near the water pump. That way i've got two, sea weed has clogged my intake more than once over a short trip or long weekend hear in the northeast.

[TrueBlue]

Regardless of condition, I've bought a new water pump impeller every year, along with the shaft zinc - replace it during Spring commissioning and have never had any water circulation issues.

I've also never thrown them away, boat's toolbox has amassed quite a collection of one-season impellers - but, at $17.50, it's cheap insurance.

[coondogger]

Or you could spring for a new impeller.

[sailortjk1]

Originally Posted by T34C

BTW- My yard, like many has a fixed rate for a lot of work, ie... there is a fixed price for impeller replacement. If it is that hard to get to, let the pros do it. Their price isn't adjusted because yours is hard to get to.

We pay by the hour. The $10 price for the part can come easliy with a $200 labor bill.

[sailingdog]

I think replacing the impeller once at the beginning of the season is cheap insurance. They're not very expensive, and if the blades break off, taking the cooling system apart to retreive the pieces will take more time than the impeller is worth. As TB said, they're only $20 or so.