'87 Johnson 70 Burned Piston

[clint]

'87 Johnson 70 Burned Piston

Ouch! Looks like you were running with clogged non working carb. Too much heat too. Probably didnt take long with all the high temp and no oil reaching that bottom cylinder. Wire burned from heat generated. Your lucky you didnt lose the whole engine. Rebuild her and you will have a new engine again! Good Luck!
Clint :'love:

 

[ddcarter3]

Re: '87 Johnson 70 Burned Piston

Ok Guys. I received the manual. I am ready to tear into this. Getting the powerhead off does not look to bad. I will take pics and post as I get things done. First question, where do I get the part numbers and who is the best to order from? I tried looking up a cylinder head on iBoats and ended up with toilets!! Doom on me. Help! Thanks in advance.

 

[andy6374]

Re: '87 Johnson 70 Burned Piston

www.ishopmarine.com

 

[ddcarter3]

Re: '87 Johnson 70 Burned Piston

OK. Got the powerhead off. Took it over to Dad's and removed the electrical and fuel systems. Looks like we can get to the rod caps and remove them through the top. The OMC Torquing Socket #331638, is this a Torx socket or do I need to order this through the dealer? Any other specialty tools I will need for this? Any other tips? Looks like the other 2 pistons are ok. I think I will put new rings on them and replace the bad piston. It scored the cylinder, we are going to try just honing it, but if it goes to far I will most likely go either have it bored or just buy the rebuilt powerhead.

 

[ddcarter3]

Re: '87 Johnson 70 Burned Piston

Bump

 

[ddcarter3]

Re: '87 Johnson 70 Burned Piston

Went to the local Johnson Service Shop. They said the rod caps need a 12 point 5/16 socket. Get a good one. Dad pulled all three pistons. Bottom one burned. Center one ok and the top one had been slapping a little. I am going over tomorrow, we are going to check the cylinders.

 

[tschamp20]

Re: '87 Johnson 70 Burned Piston

keep up the good work.you can get it right.looks like ill be right behind you with a partial rebuild.good luck

 

[ddcarter3]

Re: '87 Johnson 70 Burned Piston

Just ordered the complete rebuild kit. Pistons, bearings and the lot. Gonna have the block bored .030 over.