1965 merc 1000

hello all i have a 1965 merc that i put new plugs in and when i removed plug 1 it was smashed so i put new plugs in all 6 and was running ok fixed a couple wires and seemed better. took to local fishing hole and started it and it sounded like someone throw a screw driver in the engine and then turned it off anf started again and ran fine. so i bring it home and put the clamp to clean motor and started it and it was runnin fine then all of a sudden that noice again and then nothing. i tried starting it and it makes the sound to start for maybe half a sec then nothing. took off top cover of engine and was able to manually turn the crank shaft. what happened please help thanks eddy

Re: 1965 merc 1000

if your pistons are hitting your plugs, either your plugs are too long....wrong plugs, or you have much bigger problems. how bad was the plug smashed?

Re: 1965 merc 1000

it was not to bad it pushed the top in to the electric trode and it has only done it to piston number one and i figred out not 5 min ago on y i thing the motor stopped. i took off the top cover which has the pull start up there and was able to turn the motor over by hand. so i put the plugs back in and it crancked just fine with out the pull star on, put new plug in number one also. then i reattached the top cover and it stoped again had to turn key like 6 times to make it crank again cause it was stuck, but once it moved it keep on movin tilit jamed up again so tomorrow when i have help i will check that . as for the plugs i am usein, they are what came in the motor when i got it and they are acdelco r45. are thse the right plug? eddy

Re: 1965 merc 1000

If the plugs were too long all the plugs would be destroyed, sounds like a bad con rod bearing. Invesitgate it before you detrroy the entire engine, stop cranking it - determine if there is play by using a wooden dowel.