I have a 1998 Sugar Sand Mirage with a 175 hp Mercury SportJet engine in it
(basically an outboard power head mounted to a jet)... I've been having a
problem with it that seems to make me think that oil is being injected into
the cylinders after the engine has been shut down... When I try to start the
engine, it won't fire unless I spray a lot of starting fluid (ether) into
the air intake... Doing this will eventually result in the engine starting,
but it takes a couple of tries... Once it does start, it smokes a lot
initially, but after awhile, it runs normally... I have verified that I have
good fuel (drained the tank and examined it in clear bottles)... I have
pulled the plugs before using the starting fluid and they have quite a bit
more 2-cycle oil on them than I would expect was normal... They come out of
the engine looking like they had been dipped in 2-cycle oil... This would
explain the smoking after it finally starts using the starting fluid...
After it has run for awhile, I can restart it immediately after a shutdown
and there is not a problem... If I wait an hour, I had better have a can of
starting fluid with me... To say the least, this does not give me much
confidence in my engine and thus I'm extremely hesitant to shutdown the
engine until I get back on my trailer at the end of the day...

Has anyone encountered this sort of problem before?

Mercury says in the engine manual not to pre-mix the oil and gas, but rather
to use the oil injection tank... Since it has an inboard tank and a fuel mix
is likely to stay in there for a period of time and I've always heard that
you should not use a 'stale' fuel mix for 2-cycle engines, I'm somewhat
hesitant to go the pre-mix route...

Suggestions?