digifox

what can i do inside the engine to clean up some surf-es rust?

wcmorrison

My Feedback: (2)

What kind of engine, 2C or 4C? Does it just look bad or is the rust from the bearings? Generally the crankcase is aluminum, that being the case (no pun intended), remove the piston, con rod, sleeve and crankshaft and cook it in a crock pot filled with anit-freeze for 8 or so hours. It will make your crankcase look like new inside and outside. A 4C has more parts, more to disassemble and reassemble. Takes more time and effort (and care) but then you may know that.

But if you have serious rust, your bearings may be shot (source of rust). Time to replace them and do the clean up job also.

Cheers,

Chip

w8ye

My Feedback: (16)

Generally, the rust is down around the crankshaft and bearings. The bearings will need to be replaced. The rest of the rust will need to be removed with a oily cloth. Or you could crock pot it like stated above.

Enjoy,

Jim

Sport_Pilot

Is it rust, or just redish brown stains? The latter could be from castor oil on the hot bearings.

proptop

My Feedback: (8)

I was given an older O.S. four stroke .61 that got dunked in the lake and not dried out completely...
The inside was sort of a burnt orange color[X(]
Never seen rust that bad inside an engine...

Anyway...I use fine wet-dry paper with oil...
600-1000 grit is what I use, and try not to remove any material but the rust. You will have pitting in some areas if you have a bad case like I did.
(The little 1" dia. wire wheel Dremel attachment works well to get into some of the nooks and crannies too )

Check the wear / bearing surfaces closely with a jewlers loupe or strong magnifying glass. Look especially at the crank-pin, wrist pin, and cam if 4 stroke for pitting.
I had one h*ll of a time getting the wrist pin out of that engine, because it was sooo rusted...(had to use penetrating oil, heat, and an easy-out )

broke_n_bummin

A place I used to work had an aparatus that worked like a sandblaster, only it used baking soda instead of glass bead. It was used on a machine that did gold plating on things like phone plugs, RJ45 connectors and airbag modules. I was sitting down looking at my oilstained 120 one day and decided to see if I could mimic that process. I adapted an airbrush ... well ... adapted is pretty strong. I used corn starch instead of paint ... that is until I found out that the dust created from corn starch is highly combustable. So, now I use baking soda. It's not quite as instant as glass bead, but it does work, it's cheaper than antifreeze, takes less time and you don't have to fight with your wife over that new crockpot you just bought her for Christmas.

red_guy

bought a brand new MAGNUM 25. Both bearings and crank shaft had rust on them. Wll never buy another mag .25 again. its the second I have problems with.
I do not say magnums are bad engines. my 46 its a very good engine. but the 25s and the 28s just s$$k.

red