No Water Circulation

Ok, I have the 78 power head attached to the 59 lower unit 6hp/5.5 lower end. My water quit circulating. I just finished puling the motor apart, the Vanes on the water impeller are intact, it was replaced 8 trips ago. part 323596. Worked fine till i put motor in barrel to flush last trip. No water coming out indicator fitting or at exhaust. Splines are in good shape, Drive shaft turns propeller so shock is not an issue, no scoring on aluminium impeller housing insert in the water pump housing. Motor shifts gears and prop kicks water like normal. I blew compressed air through the lower unit water passages, through the pipe that runs up to the power head. I blew air in power head passages and air seems to come out.

What could be the problem?? Is there a thermostat stuck closed? Seems like it should be working fine. Any ideas?

Thanks, Azog

Re: No Water Circulation

yep....blown head gasket.

Re: No Water Circulation

Wouldn't there be at least a little water from indicator with a blown head gasket? The motor still runs like it did without an obvious power loss.

Just came back from vacation or I would just get another motor so I have to try to get this one running again. I am an auto tech, we test for exhaust gases in cooling system on cars but what do I do to check head gasket on an outboard other than take it apart to inspect it?

Thanks for the help, Azog

Re: No Water Circulation

nope....nada....zilch....none when mine went out. The mechanic knew my head gasket went out when I told him that water was shooting back through the muffs when I was testing it. I thought it was impeller/plug water tube/thermostat.

Re: No Water Circulation

Going with the head gasket set. Anyone know the torque setting for the head bolts? Top end is Johnson 1978 6p 6r78b.

Thanks