Bits of steel on sparkplug probably not good

[greasemonkeyjmj]

I have a 74 johnnyrude 50 horse. Twice i have pulled the bottom plug and have had small pieces of dark colored metal stuck between the electrode and the edge of my plug. Both cylinders have around 120 psi. Any ideas what the pieces may be ? I know they are steel because they will stick to my magnet.. Thanks

 

[Bosunsmate]

Re: Bits of steel on sparkplug probably not good

Rings or bearings possibly
Are they sharp edged?
Look at the piston through the plug hole you may see bits embedded on it.
If its bearings the dents are like little moon craters, with rings i find them normally to be sharp dents.
It may be something else too.

 

[greasemonkeyjmj]

Re: Bits of steel on sparkplug probably not good

I had looked at the piston earlier and didnt see any metal pieces or any spots on top of it. The pieces dont really have any edges, they are just kind of random shaped. Actually they look like rock bits

 

[boobie]

Re: Bits of steel on sparkplug probably not good

Hows the mtr run ??

 

[greasemonkeyjmj]

Re: Bits of steel on sparkplug probably not good

well at times it will run good. then at times it is only wanting to run on 1 cylinder. i have been at the lake since friday morning fighting with it, came home today and did a compression check on it. have 150 psi on top and 120 psi bottom cylinder. so it is looking to me like it is gonna be bits of piston ring. so it seems it is time for me to hunt for another engine.

 

[boobie]

Re: Bits of steel on sparkplug probably not good

With that difference in compression, pull the cyl head and take a look. You may be able to repair it for less than a different mtr.

 

[greasemonkeyjmj]

Re: Bits of steel on sparkplug probably not good

hi Boobie. i pulled the head and the piston is toast. so i pulled the powerhead, and tore it down, i have no bottom ring at all left on the lower piston. the block is in good shape with no damage. but the main bearings all sound rough, and the throws on the crank have some black spots on them that look like pitting. and the same thing with the rods. so i am not sure which way to go

 

[boobie]

Re: Bits of steel on sparkplug probably not good

IMHO, rebuilt power head or a different mtr.