Old Merc Alky stuck with castor oil

[MTECHMARINE]

I acquired an old Mark 50 alky modified powerhead that sat for years with castor oil and is thoroughly stuck. It's a really trick block and worth restoring. Anyone out there that can tell me what will soak thru and cut this stuff without beating the poor thing to death??

I'm going to try some MEK on it today - -

[Skoontz]

I acquired an old Mark 50 alky modified powerhead that sat for years with castor oil and is thoroughly stuck. It's a really trick block and worth restoring. Anyone out there that can tell me what will soak thru and cut this stuff without beating the poor thing to death??

I'm going to try some MEK on it today - -

Two things. first try Krol, it is a space age type rust cutter that crawls uphill. About $15.00 a can but well worth it.

second, stuff the ports with paper and put the covers back on. Then make yourself a 14mm spark plug insert with a grease fitting. After a thourough soaking, pump a cylinder with grease and see if you can get anything to move.

I've unstuck the stickiest stuck motors with no damage using this method. If grease does not sound good to you, after soaking with Krol, try a little persuasion from the blue wrench and a wooden drift and slight taps on the piston tops....Oooops forget, its a Merc that ones out....

Try the grease fitting if the Krol won't unstick it.

[brichter]

Castor is soluble in alcohol obviously so I would start there. I had a powerhead stuck with castor once and I soaked it in alcohol. You can buy denatured alcohol at any hardware store reasonably. It took a while to soften it and I had to use pressure (as Skoontz describes) but the powerhead I had did come apart after being securely "glued" by the castor. Good luck with the project!

[Bill Van Steenwyk]

If the engine was not run on gasoline and oil prior to storage, the problems may not be all "castor stuck". As is common knowledge, alky will attract moisture right out of the air, and if humidity was high where the motor was stored, rust and/or corrosion could also be a problem. I have never used the Kroil product myself, but have heard very good things about it, especially from gunsmiths to free up rusted firearms. If you do get it freed up, might not be a bad idea to check the rod and main bearings before trying to run it to see if they do have some rust on them. If so they would not last very long and could cause more damage to an otherwise salvageable engine if not taken care of before attempting to start. It would not take that long to drop a rod cap to see if the bearings and/or bearing surface is rust free. If not, you can pretty much figure on rust throughout, requiring rebuild. In addition, if moisture was present, rings could be rusted to the liners, possibly making hitting piston tops with anything harmful.

I heard of several engines in this condition brought back to rotating condition by soaking in a 55 gal drum with enough automatic transmission fluid to cover the powerhead, but with the price of fluid these days, that would not be cheap.

There is a person who posts as Mark 40-H or similar on HR who seems to have much experience with rebuilding older engines. Perhaps he could be of some help. I think he posts on BRF also but don't remember what he uses for a name here.

Good Luck

[MTECHMARINE]

Thanks for the replys.

I am tearing the motor completely down, have the crankcase cover off and pulled the upper end cap so far. There are no signs of any rust at all. Rods are free on the crankshaft, I can move them side to side. This thing was sitting in central Nebraska so the external environment was dry and friendly.
Just being cautious, don't want to ruin it.

I think you are referring to Doug Kay as the 40-H posting party. He has done some work for me it is totally AWESOME!

[Mark75H]

I've tried alcohol and Kroil and not had any success

[Original Looper 1]

The best thing I've ever used http://www.seized-engine.com/



Paul

[Skoontz]

Sam:

Seems to me and correct me here that if you introduce alky with any pentrating oil you are kind of defeating the purpose.
The oil lubricates and separates, the alky dries things out. thats why if you dose if with the lube, then pump a cylinder with grease it works so sweet. I've got a could electric grease guns by Lincoln we use out in the field that work great for that.

[Mark75H]

After you push the motor apart you still have a lot of pieces stuck together by the polymerized old castor. Its less than half the battle.

[MTECHMARINE]

I have some of this product and have applied same to this motor. Will try the zerk in a spark plug after it soaks for awhile. Motor stopped at TDC (or was set away after timing) so one cylinder is at BDC, that one will have to "meet the press" it appears. I'll give it a week or 3 to marinate.