Gunk removal

[old islander]

Hello all,
Restoring some old evinrudes from the 70's. When I removed the power head from the base that the cowling sits on I can see up into the exhaust chamber of the power head. It is caked with old nasty burnt on carbon, sort of like burnt tar. I want to clean that all out of there. Whats the best solvent to use along with gentle scraping to remove it all? I wont be able to sleep at night if I put it back together dirty.

 

[nwcove]

clean it up a bit by hand, put it back together.....then feed it some seafoam. jmo

 

[Scott Danforth]

spraying mercury 2-stroke cleaner or carb cleaner has worked for me in the past. Oven cleaner would work on steel parts, however it tends to pit aluminum parts.

you can also spray seafoam deep creep, let it sit for about 30 minutes to soften the buildup.