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Archimedes
05-29-2010, 08:48 PM
So I ran my boat on the fake a lake today and I noticed that there was a steady stream of water running down the prop shaft. Not a huge gusher but a lot more than a drip - a solid stream. Is that normal? I may be losing my memory, but I don't recall that the last time. I thought it was supposed to be just a drip, or is it drip without the motor running?

Also, as usual, I ran the boat for about 20-30 seconds without water like the tard that I am...hoping I didn't destroy the water pump...

TMCNo1
05-29-2010, 09:13 PM
If it has the dripless shaft log, then water will come out around the shaft when ran in the driveway, because it is cooled with water from the raw water pickup hose by a small tube and that is where the water exits when at idle or at speed.
I would still check to see if the raw water pump impeller is OK anyway. If it's damages by running dry, replacing it will maybe save you a embarrassing time at the ramp or in the water.

Archimedes
05-29-2010, 09:15 PM
Yeah, I may just do that. It pumped fine after that, once I got the water going. I just hate pulling the impeller.

Thrall
06-01-2010, 07:46 PM
Stream of water out the propshaft is normal for a dripless seal.
20-30sec running dry, I wouldn't worry, aside from keeping a spare on the boat.
Unfortunately I durability an impeller last month, first time out with a Flush Pro installed and for some reason it didn't allow water thru. The boat ran for minutes, I'm guessing close to 10 min...dry.
I ran the rest of teh day on that impeller, no issues. Swapped it out and it was barely marred/melted, still in much better shape than I would have imagined.

Archimedes
06-01-2010, 07:53 PM
Stream of water out the propshaft is normal for a dripless seal.
20-30sec running dry, I wouldn't worry, aside from keeping a spare on the boat.
Unfortunately I durability an impeller last month, first time out with a Flush Pro installed and for some reason it didn't allow water thru. The boat ran for minutes, I'm guessing close to 10 min...dry.
I ran the rest of teh day on that impeller, no issues. Swapped it out and it was barely marred/melted, still in much better shape than I would have imagined.

Thanks, that makes me feel better. I'm a dope for doing it (second time I've done it - I think I'm starting to suffer from dementia), but I'm hoping 20-30 seconds didn't kill it. It was making a whistling sound though when it ran dry.

I'm gonna bring a spare impeller when we head out to the lake for the first time.

Thrall
06-01-2010, 08:04 PM
Mine started squealing..............hence the reason I turned around..........to see a little smoke rising from the engine hatch!:eek:
I still wouldn't sweat 20-30 sec. I'm too paranoid about getting water into the cylinders when running on a garden hose, so I always start it dry and then go turn the water on. Bet my boats typically run 10-15sec at least before getting water to them.

TMCNo1
06-01-2010, 08:18 PM
Mine started squealing..............hence the reason I turned around..........to see a little smoke rising from the engine hatch!:eek:
I still wouldn't sweat 20-30 sec. I'm too paranoid about getting water into the cylinders when running on a garden hose, so I always start it dry and then go turn the water on. Bet my boats typically run 10-15sec at least before getting water to them.

I have seen impellers burn up in less than 5 to 10 seconds when ran dry. Don't be mislead by thinking it won't come back to bite you someday. We had a owner in Cypress Gardens one year on Friday start his up dry to show people how his straight pipes sounded. I warned him he was going to burn up his impeller, come Sunday he had to be pulled in from a overheat on the Chain of Lakes, because his impeller was burnt up and he couldn't find a replacement impeller.
I have always turned on the water before starting the engine on ours now for over 21 years, so don't be mislead by someone else's lack of knowledge of internal combustion engine.
Unless your exhaust hoses have been totally blocked and the impeller is toast, you should never get water in the cylinders. A good impeller will prevent any water from entering the engine cooling passages and unless the block is cracked, blown head gasket and water gets in the cylinder while running. The combustion chambers and the cooling passages are two seperate paths and do not mix on a marine engine till the exhaust and water come together at the end of the exhaust manifolds and the start of the exhaust hoses and water cannot back up into the cylinders unless the exhaust hoses are totally stopped up between the transom and the manifolds.

JohnE
06-01-2010, 09:30 PM
I'd just change the impellor. Why risk it? Rubber chunks aren't good in your motor from what litttle I know about these things. If I were betting, I'd bet it'd be fine. But I wouldn't be willing to take the chance on my boat.