RE: Removing varnish on 4 strokes??
Here's what I did and here are my results...
I bought a cheap 2qt crockpot at Walmart.
No temp control, only on or off.
It cost $9
I used undiluted Prestone antifreeze.
I let it cook for about 16 hours.
The antifreeze evidently was too hot and caused a darkening of the finish.
Is it ruined?
No.
Do I wish it hadn't done it?
Yes.
It did remove a lot of the dirt but ignoring the deepening of the engine color it doesn't look new.
Was it worthwhile?
I think I'll write off the $9 crockpot as a failed experiment and go for one with at least two temp settings.
I have a couple other old engines I may try to clean up this engine so I'll probably try it again with diluted antifreeze and cooler temps.
JLK