yamaha outboard question with video. t9.9elhp motor

Incantation · #1 (**permalink**) 10-26-2010

YouTube - VID-20101003-00003.3GP

two questions..

as you can see in the video, when i open the throttle, the motor chokes. if i keep turning the throttle it will die. this leads me to believe it's running rich. i checked the plugs and fuel filter and they are ok.. anyone have any idea what's wrong? you can hear it hiss as the throttle is opened..

also, if i open it very slowly or bounce it a bit.. it will sometime get past the choke rpm and operate smoothly.. and above that choke rpm range it operates perfectly..

lastly, what is the mechanism that moves at 0:09 seconds?

any help would be appreciated. i am comfortable working with motors but outboards and carb'd motors aren't really in my range of experience.

thank you
inc

boomer365 · #2 (**permalink**) 10-27-2010

Hello l have a 9.9 as well.

The Part moving at 9 secs is the Shift linkage.

As for the stalling on acceleration, not sure at all.

dabnis · #3 (**permalink**) 10-27-2010

Incantation,

Sounds like it may be starving for fuel?. If it has set for more than as few
weeks without draining the carb deposits can form partially blocking the
jets. If pulling the choke part way out helps that is probably the case.
If it has a slow speed mixture control you might try richening it up a bit.
Otherwise you might mix up a half and half mixture of gas and Gumout or Berrymans Fuel Additive, run it for a while, let it set for a day or two
and try it again. If that doesn't work you may have to pull the carb
and thoroughly clean it out. If it runs OK at speed under load the filter
is probably OK and there is probably no air leak? I would guess the low
speed jet is partially blocked?

Dabnis

speciald · #4 (**permalink**) 10-27-2010

Take the carb off and clean it. Also check the diaphragm in the acceleration pump.

Incantation · #5 (**permalink**) 10-27-2010

awesome.. thank you gentlemen

Faster · #6 (**permalink**) 10-27-2010

Most likely a plugged jet inside the carb.. some of these are hidden so take care to find them all. Pay attention when you disassemble the carb so you can reassemble it correctly.

If you don't already have one, maybe add an in-line fuel filter for the future.