1978 80 hpr mercury

[irishviking]

I have had this motor for almost seven years and have had no major problems with it untill last night. I started the motor and it did not sound write when it was running I went back to listen closer and it died. It madse a puff noise and it would not restart. it turned over vary hard like the battery was low. the voltage was at 12.5 volts. I took it home took the cover off thinking that maybe it was a bad ring or something of that sort. upon removing what i Thought was the head cover i found the pistons to be sealed. So i can not see anything to determine if it is a seal or ring. I did notice that there was water in the forth piston, counting down from the top 1 thru 4. Atleast there was water in the spark plug. THe motor will crank without spark plugs but not at the speed i think it should. Can anyone give me some possible ansews to my problem <br /><br /> Thanks Shawn

 

[mellowyellow]

Re: 1978 80 hpr mercury

check compression to start and post results.<br />sounds like you lost a cylinder 2 me.<br />good luck,<br />M.Y.

 

[tradin]

Re: 1978 80 hpr mercury

i have the same motor and as we speak it is in getting fixed because i also had water in bottom cylinder turns out it was just a blown exhaust gasket letting water in when it was running i could hear a banging like noise and thought the worst turns out i got lucky there was no internal engine damage the noise i heard was the water turning to steam or something like that basically it boils down to a new powerhead gasket kit and fuel pump kit the engine was cleaned in a tank and is being reassembled as we speak thankfully a buddy of mine owns a racing company and does this kinda thing for a living i would think you might have same problem hopefully with no damage but regardless if theres water theres a problem get a manuel and go from there but its going to have to be stripped down

 

[greasemonkeyozi]

Re: 1978 80 hpr mercury

Dont sweat it Irish, it dont take a rocket scientist to work on boat motors. Buy yourself a manual, read the part about power cylinders, and notice how simple it can be.