Nasty, grimy exhaust soot in leg

[wiscoboater]

Hi Guys,
Just tore down a Mark 55 for a restoration. After pulling the power head and the lower pan the leg is full of that black grimy baked on exhaust carbon. Over a 1/4" thick in spots. I’m scraping as much out as I can but getting inside the leg is troublesome. What kind of solvent works best on that crud that I could spray in there, let soak and rinse out.

[beerman57]

Scrape out as much as possible, then OMC power tune / Valvtect de-carbon, both can be sprayed inside from the ends of the midsection and are strong stuff. Spray some twice a day at first, let it sit without rinsing, maybe find a brush like a big pipe cleaner brush.

[wiscoboater]

I already found a big brush. I hope the wife does not want to clean the toilets for a few days till I can get her a new one…..

[chris-p]

Wonder if oven cleaner would work well?

[wiscoboater]

Well… at $13 bucks a can for power tune, I’ll try the $5 a can oven cleaner first.

[david-bartlett]

Oven cleaner will probably do it, but may do too good a job and attack the aluminum if left too long! Try it and let us know how it works.

[crosbyman]

the spray stuff to clean my wood granule (pellet) stove Windows work pretty good

just Google for the stuff… soot/creosote removers

tons of liquids available but will it eat into aluminum..??

Joining AOMCI has priviledges 🙂

[joecb]

Oven cleaner does a good job. I have used it to clean up the grunge on "as found" motors. Just be cautious, it will lift paint, decals and if left on to long begin to attack aluminum.

Joe B

[beerman57]

Valvtect is about half the price of OMC PT. Exact same stuff, check your local auto parts stores.

[20mercman]

I recently had to clean up two Mk-20 mid-sections and the power heads with some very heavy carbon build-up, also on our 54 Corsair. Oils in those days were really not very good! I sprayed it down over a few days with some good penetrating oil and let it soak. Every day I would give it another spray. When it was time to clean it up, a putty knife, screw driver, etc., then used Super Clean and they look like they were bead blasted. Not very expensive also. One word of caution on the Super Clean, it will permanently discolor paint, so be careful of where you let it drip or sit. If you have a serial plate that you want to preserve, tape it off.

Steve

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