On Sat, 05 Jan 2008 23:33:50 -0500, Dixon wrote:

A friend sent me this post from a personal watercraft tech chat site. If
this guy is for real he should make Darwins list;

Porting trouble


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Hey guys, I've got a 93 Superjet. I've had a pipe and modded ignition
for a while and wanted to get more performance. I was recommended to
port and polish the intake and exhaust ports. We found out they used
abrasive material to do it like gritty sand. So I got with my friend
that tunes Fords and we decided to try it ourselves. We got a bag of
sandblasting sand and hooked up into the intake and started the ski with
it hooked up to the flush kit. We had to hold the gas so it would run.
He wanted to let the engine suck in the sand through the intake so it
would port it out and then push it out the ehxaust so it would port the
exhaust port and manifold.

I was worried that it might cause problems but he figured it'd be OK as
long as we added a little more premix than usual. After running it and
letting it suck in sand we got about quarter way through a 25 lb bag.
The engine was bucking and kicking and sounding really weird. We stopped
and hooked the F/A back up normal and took off the sand supply. We tried
to start it again and it was really hard. Once started it couldn't idle
and kept making weird noises. We just kept trying to run it to blow more
sand out but it started to make scraping and knocking noises.

Help! Can anyone tell me what to do! My buddy only does Fords so he
doesn't know much about Yamaha pwc motors.
__________________
650 Superjet

(Can anyone actually be this stupid?) Dixon

Yes, they can. When I was younger I worked in production, mold-making,
and sales for my dad's company (http://www.wescottsauto.com). After a
while I realized that there's one of the main symptoms of the differences
between men and women is that a woman will happily profess to being
mechanically ignorant, while a man will happily demonstrate it to you, on
his own equipment.

I have seen friends, customers, co-workers, and customers car builders do
things to cars that go well beyond anything that I could imagine doing,
both in the 'stupid' and 'clever' directions.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html