Hot 20hp Mercury- how bad

[merc20]

I recently replaced the impellar on my 1980 model 20hp Mercury. Everything has been fine until this morning when I looked back while running and noticed no water pumping. I immediately cut it off and it had gotten pretty hot. There was steam coming from the exhaust. I finally got back to the ramp (paddling). I pulled it a couple of times and it it tried to start. I guess I just wanted to see if it was locked up. Got home and pulled the foot. Some weeds had stopped up the tube that pumps water to the block. I cleaned it out.<br /><br />I'm afraid to try to start it-- what should I look at for potential damage?<br /><br />Thanks in advance--

 

[JB]

Re: Hot 20hp Mercury- how bad

Any damage would be to cylinder walls and piston rings, I think, Merc20.<br /><br />You can do no (further) harm by cranking her up in a tank or on muffs and running her for a few minutes. Then run a compression check.<br /><br />That is a pretty tough engine. I doubt that you have done any permanent injury.<br /><br />Good luck.

 

[merc20]

Re: Hot 20hp Mercury- how bad

I feel better. I was already calling around trying to find a replacement. Thanks..<br /><br />I was about to change my user name to Nissan30

 

[andrewkafp]

Re: Hot 20hp Mercury- how bad

A good investment to save you looking at that telltale whilst trying to operate your boat is a water pressure gauge. I have an 81 Merc which has one fitted. If the needle starts moving and increases with acceleration. you know that the pump is working without having to keep watching the telltale. There should be a small connection between the cylinders to attach the tube.<br /><br />BTW Merc20 I am interested to know what your 1980 looks like? Does it have Light/Dk blue bands and silver "Mercury" with a red "20" ?