How long would it take before I would see water coming out of the exhaust bellow? I let it run for about 5 seconds or so and shut it of fearing it would burn up. Did this a few times and finally gave up. Pump wasn't hot and impeller was still good. Wondering if I just didn't let it run long enough?
i've always gone by the 30 second rule. even a NEW or emptied for winter motor that must completely fill, 30 seconds should be long enough. if it hasnt begun pumping by that point, i turn it off and give it some time to cool while i double check everything. then i might give it a full 45 seconds. but it wont overheat in less then a couple of minutes. and if its not pumping with the hose hooked up, the impeller is probably bad already anyways. however, if you do even get it near warm, its already hotter then you think it is where the heat is produced, the cylinders, and where you have tight clearances on fast moving parts, the cylinders and pistons. and if it gets too hot, major damage is quickly done. BTW, service period on a merc impeller is always 100 hours or 3 years. or NOW, before the motor is damaged, if unsure of when it was last done. when the impeller is less then $50 (and about an hour labor, if paying for it) and a new motor is THOUSANDS, you cant replace it too often. dennis, you have NO clue. i suggest getting one before you ruin the motor in your own boat. and in the meantime, keep your bad advice to yourself.
This Site Might Help You. RE: 5.7 mercruiser water pump? How long would it take before I would see water coming out of the exhaust bellow? I let it run for about 5 seconds or so and shut it of fearing it would burn up. Did this a few times and finally gave up. Pump wasn't hot and impeller was still good. Wondering if I just didn't let it run long...
Mercruiser 5.7 Water Pump
Mercruiser Raw Water Pump
If you are raw water cooled it can take up to 3 minutes for the thermostat to open, and a little mist to start coming out. You should not run the engine out of the water, or without a flush attachment.
