Shredded Impeller

[KJB]

Launched my 2000 Ski Nautique with GT40 and heater option today. Saw smoke at stern while under power. Temp guage went up to 220F, so I shut it off and smelled rubber. Obviously the impeller came apart. Besides replacing the impeller, what do I have to do to clean the rubber out of the engine - hoses, thermostat, heater core, exhaust manifolds, etc.? Thanks

[east tx skier]

Fried a brand new one on my 98 earlier this year when a belt wasn't reinstalled properly. (dumb user error). From talking to my CC mechanic, bits of impeller on the GT-40 tend to travel downstream rather than upstream. Check the hoses going to the transmission cooler and the screen on the cooler itself. All of my impeller bits were in the hose near the transmission cooler.

[DanielC]

If your impeller bits went down stream to the transmission cooler, there is a good chance you put the water pump on upside down. It is reversible, to accommodate right and left hand rotating engines.
Generally, a GT-40 engine, you put the screw head on the side of the raw water pump toward the engine. This is if the engine rotates clockwise, looking at the engine from the end with the water pump and alternator on it.

[east tx skier]

No, my pump is oriented correctly and marked for good measure and has been since the day I took possession of the boat. I shredded the impeller (which was brand new) because I didn't get the belt back on correctly after installing it. I noticed it quickly before the temp spiked and shut down. I got the belt on and put it back in. Apparently, the pump housing got hot enough for the impeller to gain a little traction and when I cranked after getting the belt on, it ripped it to shreds (looked like a hockey puck).

Replaced the impeller, retrieved the bits from the hose just pump side of the transmission cooler, found nothing upstream, and it has run like a top from that point on.

The person who told me to look downstream was a certified CC mechanic with many years of experience. I would not have looked in that direction had it not been for him. I agree it doesn't seem logical, but I have first hand experience that they tend to end up down there for some reason.

[DanielC]

OK, I am really curious on how it is possible to put the belt on wrong.
Maybe if the engine gets hot, steam pressure blows the impeller bits backwards?

[east tx skier]

It starts by having a two year old. Then you start having lots of brain farts. Then, I either forgot to put it on or got it on where it was not on around the crank pulley on the part I couldn't see when I was sitting over by the water pump. Probably the former. Yeah, I felt like a moron. On the upside, I had the good sense to raise the motorbox and have a look around right after I started it up the first time when I was on the water. I immediately noticed the belt and it was a very short trip (about 600 feet) from the launch to the lift.

The way the water pump is oriented on a PCM (versus an Indmar) the water enters the pump housing through a hose oriented vertically. When the impeller shreds, there are no vanes left to move water upstream with any sort of force. So the little bits of impeller fall down the hose. Or, if they did get a little above the pump housing, they fall right back down, there are not much in the way of vanes to keep them from falling through, and they settle somewhere in the hose near the transmission cooler.

Yes, my original plan was not to be terribly specific about my stupidity. The last time I messed something up, I didn't get the plate lined up right. Impeller survived that oops fortunately.

[DanielC]

"It starts by having a two year old."

That explains a lot, and I do not even have children.
Aggravations now will quickly be forgotten the first time the child get up on skis, or a wakeboard.

[east tx skier]

No doubt. Our now almost six year old was on skis when he was 3 and a half.

So far, my mistakes have been small ones and I rarely make them twice.