Flooding, leaking fuel, running rough, backfiring

[rusty shakelford]

  Every few years my '91 FJ will start running rough, and leaking fuel down the lower swingarm.  The #2 cyl. carb. float sticks. Rapping the carb lightly with a screwdriver never seems to fix it for any ammount of time. Draining the float bowl(s) always fixes the problem, and it's good for another few years, and that's good enough for me.
   It's really amazing how much stuff collects in the bottoms of the carb. float bowls. The job of draining them is really easy with a long philipps screwdriver, and a piece of tubing, and a coke bottle. Super long needlenose pliars work great for pushing the tubing onto the nipple at the bottom of the float bowl. Of course, extinguish all flame, and remove any lighters from pockets.
  Bic lighters will spark 99% of the time when they fall out of a shirt pocket while leaning over. I discovered this the hard way a few years back.
 
 
   
 

[jamesearthdrum]

Rusty,
Does the '91 utilize a fuel filter? If so is yours missing

[Yamifj1200]

Rusty,
Does the '91 utilize a fuel filter? If so is yours missing

My 91 has a fuel filter located under the tank.

Eric M

[Paul Dodge]

Hi Rusty,sounds to me like it's time to pull the carbs & have a look-see. On my first 90 FJ i had an issue with fuel coming out of the #4 carb overflow! I was about 100 miles from home at the time so i scrounged a 20 oz soda bottle and put the offending drain tube in it & fastened it to the bike. I didn't want raw fuel getting on the rear tire!!! When i got home i remove the carbs & took all the float bowls off.  The float needle seat (brass) is held in place by a little clamping piece & 1 screw. If you remove the valve seats you'll find that the body of the needle seat has an "O" ring on it. These harden with age & heat and allow fuel to seep past the outside of the seat body. Basically the fuel is bypassing the needle/seat assembly.. I replaced  the 4"O" rings & solved my problem. This may cure your problem although if a float is sticking it may be time to give the carbs a good "going through". The needle seat assemblys are SCAREY EXPENSIVE from Yamaha so you'll probably need to source them from a web site or some of the fellas on this FJ forum. Hope this helps.  Paul

[drawkward]

I just had to deal with a similar problem.

I bought the bike from a guy who said he had fixed all the o-rings in the seats so that it wouldn't dump fuel. When I got it home and started it up for the first time it was still dumping. So I took the carbs off and cleaned EVERY jet and passage way with carb cleaner and a compressor. All main jets were completely clogged and some other jet (don't know which) was clogged, causing the carbs to overflow.

I'd have to agree with Paul...take those puppies off and buy a couple cans of carb cleaner and use them both. Get some compressed air or a compressor and blow out all your passages. Just draining the float bowls is not enough of a clean job.

[RichBaker]

Rusty,
Does the '91 utilize a fuel filter? If so is yours missing

My 91 has a fuel filter located under the tank.

Eric M

All FJs with fuel pump (88^) have a filter mounted under the tank.....

[WIFJ1287]

Up here in the cold WI north we drain those carbs every winter and store them dry.
I stripped my carb bodies down the bare minimum 4 years ago rebuilt everything and knocked
out the center emulsion tube in each carb. I dipped the whole mess in parts cleaner. Those tubes
get clogged..put it all back together and walla!

Im running rougher again now it may be time for something like that again.