1980 merc 20hp water pump?

[lodiwi]

I put a new water pump kit in and it still does not circulate water. Is it possible for blockage to occur within the engine? Is there a clean out on the engine like the lower unit? Any help appreciated. Second question this thing as an intermittent rattle around the fly wheel. It occurs with the cowling on or off. The flywheel looks to be in balance and I cannot see any wear marks on the exterior of the engine. The starter remains in the home position and is not contacting the flywheel while running. I know something is not right but do not know where to start on this one. Got to love old motors.

 

[Laddies]

Re: 1980 merc 20hp water pump?

If your not sure where the problem is with the cooling drop the lower unit and hook a drill to it, to make sure it pumps, then a water hose to the supply line to the engine once sure get back to us. Check the flex plate on top of the flywheel for cracks in the area of the center hub.

 

[7920hpMercury]

Re: 1980 merc 20hp water pump?

Good answer on the post above.

Also too, might check to see if starter pawls (assuming it is a manual) are rattling in the pull start housing. To verify, pull off and start with rope and/or grease up the pawls and see if sound changes.

Great motors, 20 Mercury!!!

 

[lodiwi]

Re: 1980 merc 20hp water pump?

Thanks for the suggestions. I ended up pulling the flex hose from the cylinder to make sure it was clear. There was some blockage by the exit end. I also put the cups on the lower unit instead of using a barrel thinking that water under some pressure couldn't hurt. Engine is pumping water now.

THANKS

 

[technitom]

Re: 1980 merc 20hp water pump?

I'm having the same or similar problems with the water pump.
I dropped the lower unit, pulled the waterpump housing, picked all the pieces of the old impeller out, turned it upside down and tapped it with a 2x4 to get any other debris out. installed new impeller, used a small amount of "waterlube" to butter the housing, put it back together.

went to install lower unit, this is where it starts going south....

I noticed the tube on the waterpump housing and the pickup tube are not even a close fit... is this normal???
took it to the lake, no stream out of the water port. Shut it down and took it home...

I dropped the lower unit, checked the impeller it was perfect... I thought maybe a piece of the old impeller may have gotten pushed up into the pickup tube. I used an old fuel line with squeeze bulb and slid it on the fitting on top of the motor to try and backflush the system... no luck there. I slid the hose on the end of the pickup tube where the waterpump attaches and squeezed like hell...

I finally got a little water to come out of the top but most of the water was running back down inside the shaft housing... whats up with that?

I slid a screwdriver into the tube and gave it a few gentle taps to makes sure the tube was seated all the way in and tried again... same results, most of the water runs back down the inside of the shaft housing. anyone got any advice?

 

[technitom]

Re: 1980 merc 20hp water pump?

sorry for the long post