1986 johnson 150 gt piston rod failure

[Jl1958]

I have a 150 gt that has suffered a rod failure . Upon further investigation I found that the starboard head lower cylinder had a build up of substance the consistency of hard tar on it . There is a hole in the block , the needle bearings had melted to the crank shaft. There was the same buildup tar like substance inside the crank case on that cylinder as well as the underside of the piston . It is like there was a combustion occurring all around that cylinder. Any thoughts on this, all other pistons look good. Is there a way to post video to this forum.

 

[racerone]

Inspect the carburetor that feeds that cylider.----Perhaps a blockage.-----Piston was too hot.----Water pump maintained ?----Water diverters inspected ?

 

[racerone]

Should be lots of used parts ( crank and rod ) on E-bay.