Burnt piston and burnt cylinder wall, How should I repair?

[sandman]

Some of you have been kind enough to help me with my 1990 40 HP Johnson TJ40ELESR. I now have the power head off and found what I suspected. My lower piston is shot (burnt) and the cylinder wall is burnt. The cylinder head (cover) is also damaged. I am wondering what is the best repair? Do they make sleeves and over sized pistons for these? How much can you bore cylinder wall? Any thoughts are appreciated. Any suggestions for locating parts are appreciated.

 

[trevorcday]

Re: Burnt piston and burnt cylinder wall, How should I repair?

You will need to have the cylinder re-bored and an oversize piston fitted. If the scoring in the cylinder is beyond the max. oversize piston a sleeve can be fitted. Your best bet is to take the block to a suitable machine shop and have them machine it AND furnish you with the appropriate piston. Too many times I have ordered pistons, told the machine shop to make the hole 0.015 over only to find that it didn't clean up at 0.015 and it needed the next oversize...The long and short of it is that a good small engine machine shop will be able to figure this out for you.

 

[sandman]

Re: Burnt piston and burnt cylinder wall, How should I repair?

Thanks for the suggestions. I will call the machine shop to see when I can drop by to say hello. Any suggestions are appreciated.

 

[DJ]

Re: Burnt piston and burnt cylinder wall, How should I repair?

Sandman,<br /><br />If you are going to do the disassembly/assembly yourself, I would get machine shop recommendations from a Johnson dealer you trust. Tell them you'll buy the parts from them.

 

[sandman]

Re: Burnt piston and burnt cylinder wall, How should I repair?

Great Idea.

 

[wcyoung101]

I hate to post this on someone else's thread but I really need help with this. Does anyone have any opinions on the health of this outboard

 

[racerone]

I think you need a replacement block for that " big bore " model 235 / GT 175.----Your location ?