FUEL /CARB OR ELEC?

Sun Jan 12, 2014 6:24 pm

Hello! i have '48 Cub. yesterday I plowed heavy wet snow couple of hours with no trouble.Toward end of downhill drive encounter lot of slush and water. I had to all day back up and run full steam downhill to push snow and ran hard into bank-only way I could move the snow.Anyway,I had no trouble until I make 6-8 passes pushing water slush -some of which splashed back toward tractor.All of a sudden engine started to spit/sputter-it never stalled just lurched as i backedup pulling choke out and in until i got it in garage. it ran 1/2 hour choke pulled all way out,while i hand shoveled.i started it today will run very rough with choke pulled out all the way.push in to run normal and runs right 1 second then starts to die until choke pulled all out again. the sed bowl is clean-clean fuel with lead sub added. i did not take fuel line off at carb,to see if steady fuel,but sed bowl clean.I noticed bowl has small space at top with no fuel,bowl doesnt leak,and brass nozzle inside bowl is in the fuel. I have never rebuilt the carb,it looks like original. What do you think? carb problem,fuel lock-not getting enough? How do you fix that? I appreciate any advice you can give-again the sed bowl is very clean-nothing but fuel-but little space at top. Maybe fuel lock-for some reason-not enough getting to carb unless full choke? Thank you for your help!!!

Re: FUEL /CARB OR ELEC?

Sun Jan 12, 2014 6:31 pm

You add lead to your fuel?

Re: FUEL /CARB OR ELEC?

Sun Jan 12, 2014 7:07 pm

I would check for trash in the gas tank outlet, since sediment bowl is a little low. Running downhill might have helped something move into the outlet. If not that, pull and clean main jet before tackling carb job. It does sound like fuel starvation somewhere along the line.

Re: FUEL /CARB OR ELEC?

Sun Jan 12, 2014 7:10 pm

Concur with Rick.

Re: FUEL /CARB OR ELEC?

Sun Jan 12, 2014 8:13 pm

sounds like some washed loose in gas tank.---when you go ramming into stuff, thats usually what happens. gas slopping forward in the tank may have loosened sediment from the top side of the tank then let plug the bowl inlet or go into the load jet in the carb!--- simple cleaning job should get you back in the rut! thanks; sonny

Re: FUEL /CARB OR ELEC?

Mon Jan 13, 2014 7:45 am

I'd pull the main jet and clean it. You can easily check fuel flow while the jet is out.

Re: FUEL /CARB OR ELEC?

Mon Jan 13, 2014 9:35 am

Same thing happened to me a couple times while plowing this winter. turned off the gas, drained out the float bowl, pulled metering jet and blew it out, the sediment bowl looked clean, so i left it alone. started back up and ran like a champ until it happened again a couple of days later, so i did the same and also cleaned the sediment bowl and replaced the screen. no problems since.

Re: FUEL /CARB OR ELEC?

Mon Jan 13, 2014 10:10 am

I will check sed bowl for debris,also I will clean main jet. the threads on bowl strainer(bailer and nut) dont get real tight.there is no leaking over the rim of sed bowl.Im wondering if I should get another bailer/nut that will tighten further.Is there any made of steel with stronger threads?

Re: FUEL /CARB OR ELEC?

Mon Jan 13, 2014 11:14 am

Rmankty wrote:I will check sed bowl for debris,also I will clean main jet. the threads on bowl strainer(bailer and nut) dont get real tight.there is no leaking over the rim of sed bowl.Im wondering if I should get another bailer/nut that will tighten further.Is there any made of steel with stronger threads?

Also look down inside the tank at the fuel outlet. Make sure there is no debris blocking that opening.

Re: FUEL /CARB OR ELEC?

Mon Jan 13, 2014 2:15 pm

In using compressed air to blow out main jet,is there any precautions to observe? What is the petcock on fuel strainer assy? Is that the brass tube that fits down into gas in sed bowl? Can i stick piece of small wire up into tank there help clear anything? The main jet or metering jet are the same right? I am a novice in working on these areas.Thank you for your help!I have used lead substitute and fuel stabilizer,since we got tractor. would adding anything to fuel help these things or no? Thanks alot!

Re: FUEL /CARB OR ELEC?

Mon Jan 13, 2014 3:20 pm

for the main jet, just remove it and blow it out. I would drain the whole bowl to be sure nothing remains in there. Also, When you clean the strainer bowl you should watch as it fills back up. If it fills quickly, you'll know it's not blocked in the tank. I only add sea foam to my fuel, and only that because i've got some carbon issues and those little passages in the carb like to plug up with varnish too.

Re: FUEL /CARB OR ELEC?

Mon Jan 13, 2014 4:51 pm

Thanks for this advice-all these tips help me alot! I will look to see if it fills fast,and all the way to top. This sea foam-is that all I need for name to get from Oreillys or autozone? I will get some if it helps keep this from happening.My Dad bought this '48 from strangers, I assume my Dad did work on it to some degree,because He modified the exhaust to run underneath like '57 model instead of straight pipe above fuel tank. I used to use both tractors every year- one for snow,the other for mowing grass and garden work. But for over 6 years I didnt touch either one.

Re: FUEL /CARB OR ELEC?

Mon Jan 13, 2014 5:37 pm

Seafoam is the greatest stuff. I use it on my '07 Grand Prix, '78 Phoenix (brake booster application) and in the tank of the the Super A and our boat. You can get it anywhere. Walmart, Autozone, Napa, Tractor Supply, pretty much any place that has an automotive section.
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Re: FUEL /CARB OR ELEC?

Tue Jan 14, 2014 6:09 pm

Rmankty wrote:I will look to see if it fills fast,and all the way to top.


The sediment bowl is not the best place to check for fuel flow. If the system is tight, and the float is seating properly, air in the line between the bowl and the carb will prevent the fuel from flowing freely. You would be better served to pull either the main jet (the brass hex head on the side of the carb) or the drain plug on the bottom of the carb bowl, put a container under it, then open the fuel shutoff at the tank, and check the fuel flow. If you don't get good flow there, pull the fuel line from the carb and re-check. If you don't have good flow there, work your way back to the tank to isolate where the problem is.

Re: FUEL /CARB OR ELEC?

Tue Jan 14, 2014 10:37 pm

bythepond88 wrote:The sediment bowl is not the best place to check for fuel flow. If the system is tight, and the float is seating properly, air in the line between the bowl and the carb will prevent the fuel from flowing freely.


you're right, if the float valve is closed the fuel won't go anywhere. However, if you've drained the carb to remove debris as i said, the valve will then be open, allowing you to view (through the sediment bowl) the actual speed at which the fuel is flowing out of the tank under sealed conditions.