I've got a mower that's about 30 years old now, was in the trash when
I got it, up and running now. What I found was it really, REALLY
wants 91 octane gas. With 87 and ethanol contamination, it kind of
sputters along. If the thing is really old, you might want to invest
in some lead replacement additive for the valves, unless it's a 2-
cycle. Engines with an unknown service history tend to get a lot of
oil changes at first, no telling how many hours it was run with the
original fill. I try not to run too many solvents through old
engines, no telling what will dissolve unexpectedly.
I use Yamaha "Ring Free" addative in my 225HP 2-stroke outboard. It is
supposed to stop carbon build up and stuck rings. It does seem to
I had an old snowblower with a flat head (valve in block) B&S engine.
Because of the flat head the cylinder head was easy to remove so I
pulled it just for the heck of it. There was fairly heavy carbon
especially around and on the valves. I ran a "shock" treatment of Ring
Free and pulled the head again. The carbon was cleaned up pretty darn
Only downside is the price of the stuff but considering the price of a
new O/B it's cheap insurance.
Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here.
All logos and trade names are the property of their respective owners.