[nate379]

I have a 1999 GT tractor, 20hp Briggs motor, 3 speed trans with a hi/low.

It hasn't run well for a while now, though it wasn't too bad during the summer.

Now that winter is here, I can't get it to run decent at all. It's hard to start, won't run without the choke pulled out.

If I take the choke off it starts running really rough. With the throttle wide open maybe going at 100-150 rpm. With choke on runs a little better though it's blowing black smoke and seems like only one cylinder is firing at times.

The carb has a recent kit in it, new fuel pump as well, new filter too. It's been doing this since I owned it but this year it's much worse. It carbon fouls the plugs and after I get done mowing the yard or snowblower I smells pretty bad of exhaust... enough where people say something.

It doesn't use oil, I think over the whole summer I added about 1/2 a quart. That was with mowing 1-2x a week, each time running the tractor about 2 hours.


I'm wondering if maybe I have weak spark, like the ignition controller is going bad maybe? One of my friends has an ignition tester that is meant for cars, I am going to see if it might work on that little engine maybe?


Very much making me want to sell the whole deal and buy a decent diesel CUT, but I don't have the $20k for one.

 

[4x4_Welder]

I had one do this sort of thing to me, it turned out the filter foam in the gas cap degraded and fell into the tank, partially plugging the inlet. I blew the line out from the fuel pump end, and then cleaned the tank, and had no more problems.

 

[nate379]

I've had the tank out, replaced the fitting on the bottom (was leaking) and also put brand new fuel lines.

 

[F250Highboy77]

Drop the bowl on the carb too as well as what 4x4 Welder and Nate379 said. Maybe even clean out the whole carb while your at it.

 

[nate379]

Already did that.... several times.

I don't think it's a carb issue.

 

[cobra39]

Have you checked the spark at both plugs. Two cylinder engines will run but poorly on one cylinder.

 

[Dude11]

Won't run without choke is and will always be the lack of fuel,in my book anyway.You just need to ck every thing related to fuel delivery.I'd start at the gas cap and work my way to the carb.I bet it's something you've already been over and just missed it,happens all the time.The fouling plugs are just a cause of incorrect air & gas mixture,if they are good to begin with.And,it's winter $ cold as **** in your parts,of course you need some choke to start it and "feather" it as it warms up to running temp.Remember--even Elvis cleared his thoat before singing.:trink40:On the firing---remove both plugs then grd.only one to the block and spin the eng.Ck both of them,you should get good redish blueish fire,if not then you got to run that rabbit as well.Good hunting to you,post what you find.

 

[DIRT Dog]

I agree with Dude!It's starving for gas.Try some Sea Foam fuel additive.It works on my 22.5 Kohler when it has the same symptoms.

 

[nate379]

Forgot to mention I bought the tractor in 2008 and it's been doing this since then, just worse this year.

Everything in the fuel system has been either replaced or inspected. Motor has decent compression.

I am thinking it's more a spark issue, but I dunno. What would cause a weak spark on these motors? I went to school for auto and diesel tech, small engines are kind of the same, but not something I have messed with too much.


I realize that it needs choke to fire and run, but it should be able to run without it after a while. Won't run without choke, runs like turd with the choke, but runs. (misfiring, running on 1 cylinder, blowing black smoke).

I wish I had an extra ~$15k handy cause I'd have a 1 series John Deere in the shed and this this would be brought out to my favorite shooting spot to be put out of it's misery!