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86 Merc 25 Water Flow Issue

J

jmatura

New member
Recently purchased an 86 Merc 25 and replaced upper and lower adapter gaskets, inner and outer exhaust manifold gaskets, head cover gasket, and new water pump impeller.

There is no thermostat housing on head cover.

When running mtr in test tank and water a few inches above cavitation plate barely any water comes out of pee tube, I could spit more. Along with blue smoke exhaust.

I have ensured impeller is not slipping on hub and little flat key is in place. Any ideas where to start?
 
racerone said:
Water level MUST be 6 " above the pump.----These pumps are not self priming.
Click to expand...

Thanks for the help! I did increase water level and reved up mtr in neutral and much more water peeing out, but not a solid stream as expected. But important to note plastic smaller orifice in bottom cowl gone, just exiting 1/4" tube... Does this sound right?
 
Get a new pisser for the end of the hose and see if you get a steady stream. It could be exaust gas bubbles getting in the water jacket?
 
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