Don,

I am sure getting lot's of practice removing and reinstalling the carb. What finally
worked for me is when I took it in to a really competent mechanic. He located a jet
I wasn't even aware of, the mid-range jet, which was hiding under a plastic cap. After
cleaning that, I was able to put the engine in gear without it dying out. I then ran the
engine in gear at slow speeds for about a quarter hour and it smoothened out
and seems to be ok now. This mechanic did not think much of the Sea Foam I used
in the gas tank because it was not backed by any engine manufacturer. He recommended a
product of Mercury called QuickSilver or QuickClean. One ounce
of that treats 4 gallons of gas. He maintained that using that product would keep my
engine trouble free. I too can now pull the carb in about 15 minutes. What worries me is
that I'm working over water and can easily drop something overboard. I put
a 'catcher' under the engine, just in case, but you know about Murphy's Law about
if anything can go wrong, it will. If any of the car manufacturers had this kind of
problem, they would be out of business. Yamaha sent me an email today about considering an
upgrade to their new line of 4-stroke EFI engines to save fuel consumption. If they make
those jets any smaller we will save lots of gas, but stew in frustration over the
maintenance. Makes me wonder if these engine manufacturers
are living in the real world, or some fantasy one.

Sherwin

Don W wrote:

Sherwin,

I've got basically the same motor that you have
and I've had to pull the carb and clean the jets a
couple of times since 2000. Fuel stabilizer
helps, but it also helps to be able to pull the
carb and take it apart yourself.

Once you do it, you'll realize that its really
simple to clean the jets, and probably only takes
15 minutes or so to remove the carb, disassemble
it, clean the jets, reassemble it, and put it
back on.

If you're really having problems you could do that
at home before you take the motor back to the boat.

I fought a finicky motor for two years before I
finally got disgusted, and pulled the carb myself.
You can get all the parts off of the web, and
you won't even need to replace any parts if you're
careful.

That motor sure is quiet and clean running when it
is running well.

Don W.

sherwindu wrote:

Yours is an interesting theory, and you can't argue with success. However, it sounds

like leaving the gas in (Stabil or not) is asking for trouble as that gas will dry
up, given
enough time. You have to really have faith that Stabil will not allow a residue to
remain
behind. Besides, even the Yamaha manual tells you to run all the gas out of the
engine.
I would really like to see a definitive report from a Yamaha designed on this whole
issue,
but will probably never see it. Maybe there is another factor about your case that
would
explain your successful storage of the engine. Right now, I'm a bit skeptical about
your
methods.

Sherwin D.

Mys Terry wrote:


On Thu, 04 May 2006 01:16:08 -0500, sherwindu
wrote:


This is the second season I have taken my Yamaha T9.9 out of storage and had
problems
getting it to run properly. I took extra pains to put it away properly last
year. I used Stabil in the last tank of gas. I also ran some Sea Foam through
it. The
engine was run out until it would not start. I fogged the engine at the end and
opened
a drain plug on the carb to empty any remaining gas. The engine would barely
start
this week and would die when put into gear. I cleaned the jets, but missed the
jet
for mid-range running that was hidden under a plastic cap. My friendly outboard
mechanic
found it and showed me it was blocked. After cleaning this jet, the engine
finally ran. I am using fresh gas, so that was not the problem. I have a
filter on the
gas tank, and there is another one on the engine. It is possibly a combination
of the
newer formulas of gas and the design of these later model four strokes (mine is
a
2002 with less than 50 hours on it). Some people recommend running the engine
at
least every 3 weeks, which is not always possible, and what about winter
lay-ups?
My mechanic recommended using a Mercury product for cleaning carbs that is added

to the gas tank. I am skeptical, but am trying it any ways. I never had any
of these problems with my old two strokes. That's progress!

Sherwin D.

I have the same engine, and mine started right up and ran perfectly
after 6 months of winter storage. The difference in our methods is
that I do not run the engine dry and drain the carb. I leave them full
of gas with stabil.

You have already discovered that storing it dry led to a clogged jet.
That jet wasn't clogged when you put the engine away.