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Vp 57 270 overheating

M

mrproduxn

New member
have sw cooled 5.7 with new im

have sw cooled 5.7 with new impeller.completely removed rusty thermostat.cleared out all coolant lines of broken impeller parts.can blow air from outdrive up to impeller pump.motor hits 220 degrees quickly.checked all hoses and clamps.intake tube on transom looks good.not getting good flow thru pump.with outdrive submerged in water tank appears to be no water pickup.tried priming pump and hoses and got a brief splash of water.does this require closed thermostat to create pressure for impeller system or is there possibly a deeper problem.never had any overheating issues except the seasonal impeller breakup.please advise.it is 96 degrees and my boat is in the driveway.what a waste.}}}}
 
"The most common source of air

"The most common source of air ingress (other than a faulty impeller) is the hose connector in the outdrive being wasted away. Make sure this is not your case.

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replaced that connector 1.5 ye

replaced that connector 1.5 years ago.this overheating just developed after replacing impeller.am going to put new o-ring in impeller housing tomorrow as new one did not come with impeller.re-used old one after cleaning which may be air source.one question i do have is does the impeller seat tight inside body or only where cam is located-the one sold to me appears to have 1/16" gap at 90 and 270 degrees (without shaft inserted) from cam location.seems that this would prohibit pressure.the round body cavity is 2-7/16" and the impeller dia is also 2-7/16".then the installed cam is approx 3/16" or more creating an egg shaped bore.i assume that pressure only matters at the water entry and exit flow orifices.
regarding the schematic you showed is there any simple way to access the inside area of the grids to remove any missed chunks of old impeller.i have been fishing out pieces with small tools.
 
"To access the grids you have

"To access the grids you have to remove the lower gear housing. I am surprised that you have bits of the old impeller down there, but obviously this seems to be the case."
 
believe it or not there were 2

believe it or not there were 2 complete fins from the old impeller down there.had to use pliers to get out.got a couple of large pieces in the weep hole under the lower unit also.when parked and flushed in december ran for an hour in the 160 degree range prior to removing block plugs for winter.started it memorial day weekend and thats when it ate impeller and temp jumped up to 220+.knew then that was bad because water was escaping all around my flush ears which had never happened.major impeller grenade blockage.attempted to run and cool so much today that pulled and inspected the new impeller.needless to say the lubricant had baked off but fins look ok.hopefully new uncrushed o-ring will fix it.but just in case please send all suggestions.
 
"problem found-lower intake ho

"problem found-lower intake hose for impeller pump had tiny tiny pin hole.replaced hose and clamps.lets go fishing !!!!!
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