A shear key, in general, is a rectangular piece of metal put into a slot cut
into a round shaft. The purpose is, should there be a major malfunction, the
key will shear off before some more critical part is damaged, which is what
could happen if the shaft is splined.

Other then a familiarity with the general principal of two strokes I am not
what you would call really up on the details of their operation so this is
more in the form of a question rather then a suggestion.

Reading what the Eddy has done to date I can't help but wonder, with dry
plugs, if there is some sort of "timing" problem involved. Some way that the
intake port is not open when the pistons are in the proper position?.

--
Mike G.
Heirloom Woods

www.heirloom-woods.net
"edwin van gorp" wrote in message
om...
Hi Guys,

Thanks for the tips.

I've checked and cleaned the jet again (was clean already) but this
carb doesn't have needle. So couldn't check that one. It has a valve
that opens up or closes with throttle movement.
There is fuel in the bowl and float seems to work fine.
Tried squirting fuel in the carb and related to the amount of fuel the
plugs still seemed relatively dry. I got one loud explosion which
seemed to come out of the exhaust.
Another thing is that the upper plug gets wetter than the bottom
plug?!?
Compression is fine. Not sure what a sheared key is (I'm Dutch)

Getting fitter and fitter with every tip. That's positive though
(bloody manual start ;-))

Eddy


Derek wrote in message
. ..
On 26 Jun 2004 06:40:21 -0700, (edwin van gorp)
wrote:

Dear Friends,

I'm trying to fix an old 2-stroke mariner 28 Hp and I keep running
into the same problem.

I have cleaned the carburator about ten times but when I try to start
the sparkplugs stay dry even with full choke and full throttle! It's a
manual start so I'm starting to look like schwarzenegger!

I've checked these points:
The fuelpump squirts out fuel when trying to start.
When carburator is open I can blow through the nozzle (no
obstruction).
Tried sheet of paper in front of air-filter - sucks in air.
Plugs spark (nothing to do with the fuel though).

And now..... I don't know any more.

Maybe you have some good ideas.

Thanks

Eddy

OK, here's my thoughts.

You have spark but the plugs aren't wet. Try squirting a little fuel
into the carb, see if something happens, see if plugs are damp.

If no joy, remove flywheel and see if key is sheared. If all seems
fine, I'd still suspect the carb, unless your compression is
non-exisant.