sherwin dubren wrote:
For years now, I have been fighting the problems keeping my 4
stroke Ymmaha T9.9 running. Even with adding preservatives to
the gas tank, replacing the fuel delivery system, and adding
a 19 micron filter inline with the gas feed, the tiny jets on
this engine occasionally block up. Nothing helps short of tearing
down the carb to clean them. Most of the modern gas engines have
these small jets that continually block up. Gasahol is mostly to
blame either because it dissolves any loose dirt in your system
or breaks down into something that eventually blocks the carbs.

Now we have an increase of alcohol being pushed by our farmers
to 15 per cent instead of the current 10 percent. This is sure
to make the problem worse. The engine manufacturer's have not
come up with a really good solution. Just band-aid fixes like
adding inline filters and preservatives to the gas. This is
taking all the fun out of boating and can even be a safety issue.

Sherwin
I have fuel infection but that is also susceptible to clogs and
failure. I have been using this in my boat and ATV for years will good
results:

http://www.seafoamsales.com/motor-treatment.html

It's a lot cheaper than Yamaha's version of the same product.