Minto 170

[Hotrod34a at aol.com]

    You know, I don't usually say to much and keep my mouth shut most of the 
time on this list, but it's time someone spoke up on this issue.  In the last 
several months there has been several thousand posts on this discussion group 
about 2 strokes, adjusting pipe length and tuning 2 strokes, bearing issues, 
sealed vs not, stainless vs not, after market vs standard factory bearings, 
gee, I got 200 flights on my stainless bearings vs 30 flights on the factory 
bearings, after run oil for 2 strokes, whether to use it or not, whether to run 
them dry after flying or not, dual plug heads vs single plug heads, and so on....
    In the last several months I have only seen less that a dozen posts about 
a YS engine, and most of those were how to type questions, not problem 
issues.  Last week there was one post about which port to hook up the return fuel 
line to, and Don Ramsey's problem with his YS.  How do you figure that you could 
not get a word in edgewise?????  I guess that when some folks start flying 2 
strokes, they forget how to count........As some would say....flame suit 
on.......Larry.....

Brian,
Interesting ying and yang here on engines.  2 stroke tuning problems don't 
arise that often, and last week you couldn't get a word in edgewise for all the 
YS blues!!

it's not common that the midrange would be lean, especially on the full 
Mintor setup.  I haven't seen that.  The pipe is an essential part of balancing the 
mixture in a 2 stroke and I know the Mintor pipe produces an even mixture, 
even if not top power.  Please check the engine cooling.  This can significantly 
affect performance.  Fly with the cowl off for comparison.  If there's a 
difference, then maybe you need more exit area, or another hole in the bottom of 
the chin cowl behind the engine.  
    If the engine is lean in midrange it will get very hot in the air and 
this is not good.  I've seen one engine where the owner decreased teh pump 
pressure so much that it went lean in midrange and he nearly burned it up.  Are you 
still at the factory pump setting?  If you've decreased the pump pressure, 
then increase it again.  If you are flying 10%, then increase to 15%.  Some 
engines of early vintage prefer a bit more nitro.  Another way to richen the 
midrange is to shorten the header.  This is not my first suggestion though, because 
the factory setup works fine, however I've experimented with doing this and 
found that the 170 will gain a lot more power on a slightly shorter pipe at the 
expense of a richer midrange.  Normally, this is a bad thing.
   I have had good luck with setting everything a slight bit rich on the 
ground.  This is not because I'm expecting it to lean out in the air, but because 
I think it helps the engine slow down faster and it doesnt' spool up on 
downlines.  

--Lance
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