This piston is out of a 115 1981 johnson V4 that came off a boat that i bought, im rebuilding the motor and was curious why the piston did this. And if i should look into why this happend and make sure it doesnt happen to the new pistons when i install them.<br /><br />if you look at the piston from the top you can see one edge of the dome looks burnt off, and all around the edge of the piston its very rough. Also it looks like there is melted metal flakes like on top of the piston.<br />
<br /><br />If you look at it from one side you can see that the wristpin is recessed a little bit and some of the ring is actually gone. also there a lot of scratches in it.<br />
<br /><br />on this side of the piston it shows the wristpin out to the edge of the piston. there is also a cavity that you can see better from this angle than you can from top that actually goes behind the top ring. I think this is why i was getting 10psi. compression on that cyllinder =).<br />
<br /><br />Anyways i hope someone can fill me in on what i should look for and do before i put this motor back togather, i decided to just bore it .064 over and do all 4 pistons. This piston caused a pretty major scuff so i think i gotta go all the way on the boring =(.<br /><br />Koltar
![pistontop.jpg](http://zagg.freewebspace.com/piston/pistontop.jpg)
![piston0.jpg](http://zagg.freewebspace.com/piston/piston0.jpg)
![piston1.jpg](http://zagg.freewebspace.com/piston/piston1.jpg)