Any ideas as to why water pump works only at high rpms?
Does not spit water out the back at idle, but when put into gear and revved up, it does.
A hand transfer pump was hooked to the water tube while lower unit was off and water pumped though it.
The drive shaft was turned while lower unit was off and water came up though the grommet.
A new impeller has been installed.
Thanks,
G
Worth a look to assure that the crankshaft to driveshaft splines are not worn out.
Maybe the little pin that keys the impeller to the driveshaft is missing or not engaging the impeller (short).
Impeller vanes not flexed in the proper direction when stationary.
Pump bottom plate worn excessively.
Okay, we ran the motor in the lake, still on the trailer, backed up far enough to submerge pump housing.
Same result.
Actually that was the initial test day before yesterday. Today we took it apart (got it down to 10 minutes) and it a new (different) pump housing. Clean and everything. Not pitted or worn.
Same result.
Var strange indeed.
Not splines.
Not bad impeller or improperly installed.
Tested roperly.
Not key or pin issue.
Not worn plate.
Var strange.
G
Is the impeller plate sealed against the gearcase housing? Is the air bleed hole in the top of the impeller housing open?
Those were going to be my next suggestions. But you said you already changed the pump housing so that sort of eliminates the bleed hole idea. What’s left? Plate sealed to top of gearcase (sucking air)
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