Yeah you're right about 2-strokes and compression tests (picky picky,)
however it's a rule of thumb I have followed simply because I want to
be consistent in what I do and it does indeed make a difference in
4-strokes. I didn't think about it when I said it... but I feel it
remains a good "rule of thumb" anyway.

Also with regard to discolored paint on the block; you're right
although one of my engine blocks has slightly discolored (gold) paint
and it's still perfect despite the fact it overheated once for about 1
minute before I shut down. While the paint on the block isn't pretty,
everything inside is (I pulled the heads and inspected thoroughly.)
Discolored paint on the head is a clear warning sign that there MAY be
problems. If I were buying a new engine and saw discolored paint or
anything else that indicated overheating, I would want to pull the
heads before I bought it. What's the cost of a head gasket compared to
a total rebuild? Another thing to look for is melted or disintegrating
insulation on the wires around the head (anywhere on the wiring
harness.)

I agree that old engines can be worthwhile - I have a 1972 Evinrude 85
that runs like new and outperforms my much newer Suzuki DF115. Of
course comparing any 2-stroke to any 4-stroke is a little bit of apples
vs. oranges, but I'll take my old oil-burner over a much heavier
4-stroke any day. I will say I like the quietness and lack of smoke
from the zuki thought.

Jeff


Billgran wrote:
"Chehalis Jeff" wrote in message
oups.com...

Remember,
always do compression tests with the throttle wide open.



Just for kicks, take a compression test on a two-stroke motor with the
throttle closed, throttle open, and your hand over the carb blocking off all
air flow. You will find that the compression numbers are all very close. Why
you ask? Because the exhaust port is open to ambient air until the piston
ring closes it off. On a two stroke, the compression only builds when the
exhaust port is closed off by the top ring. Try it, if you don't believe.

Bill Grannis
service manager