Stuck Jet

[steveTVC]

So I got this carb semi clean and apart. I am hung up on this jet I cannot get out. The first try was with too small of a screwdriver and the head chipped a bit which made it harder to get a grip. I used a hammer to punch the screwdriver in deeper and get a better grip but now it still seems stuck. I tried heat and pb blaster and it still doesn't budge. Should I try an impact? I also have heard of drilling it out with a 9/16th then using a torx bit to drill it out. Any suggestions?

 

[Jim L WA]

Just my opinion, but I don't think it's worth it to take it out. Just make sure it's clear.

 

[steveTVC]

So where is the other end of this jet where I should blow air and make sure it is clear? Where the needle seat hole is?

 

[Jim L WA]

If you stuck the straw from a can of carburetor cleaner down it, squirt the cleaner into it and see the cleaner exit somewhere then it's clear.

 

[steveTVC]

I got it out today! Now time to rebuild with my steiner kit

 

[Mad Farmer]

So where is the other end of this jet where I should blow air and make sure it is clear? Where the needle seat hole is?

I got it out today! Now time to rebuild with my steiner kit

That was the idle jet.

I attached a service manual PDF for Marvel TSX carbs. It has schematics of all the passages , servicing, and tuning/troubleshooting sections.

Explains well how the carb works and was designed with how fuel/air flows at various throttle openings.

It also is followed by Zenith carb section.

 

[Tom H.]

YEAH!!!!!

great to hear.

 

[steveTVC]

Got it back in and still no start. I replaced the petcock and cleaned out the tank. It looks like there was a new gas cap installed at some point which allowed water to enter the system.

When I added fuel to the tank it would not flow out so I was guessing there was a vapor lock. I unscrewed the fuel line at the carb to get it flowing. I screwed it back in then it seemed like the fuel stopped again without filling the bowl on the carb. I tried starting and got one pop then nothing. I don't think the fuel is moving through the system because the filter is only filled on the bottom end about an inch.

Should I unscrew a brass screw on the top flange of the carb to allow the rest of the air out of the system and get the fuel flowing well or is it not the fuel? I am tempted to buy a $50 carb off amazon and try that next just to rule out me rebuilding the carb wrong.

 

[pomester]

Got it back in and still no start. I replaced the petcock and cleaned out the tank. It looks like there was a new gas cap installed at some point which allowed water to enter the system.

When I added fuel to the tank it would not flow out so I was guessing there was a vapor lock. I unscrewed the fuel line at the carb to get it flowing. I screwed it back in then it seemed like the fuel stopped again without filling the bowl on the carb. I tried starting and got one pop then nothing. I don't think the fuel is moving through the system because the filter is only filled on the bottom end about an inch.

Should I unscrew a brass screw on the top flange of the carb to allow the rest of the air out of the system and get the fuel flowing well or is it not the fuel? I am tempted to buy a $50 carb off amazon and try that next just to rule out me rebuilding the carb wrong.

There should be a drain plug at the bottom of the carburetor. Remove that and observe fuel flow thru the system, you should catch a pint of gasoline in a minute or so. If not, there is a problem between the fuel tank and the carburetor bowl.

Common problems include:
- clogged inlets into the settling bowl from debris/scale in the gas tank.
- non-original inline fuel filter not appropriate for gravity fed systems.
- clogged screen on the brass elbow where fuel enters the carb. I see from your picture you have a new one, so that seems unlikely.
- stuck inlet (needle) valve in the carb/mal-adjusted float. If the float is bent a bit it can rub on the sides of the bowl and not allow the valve to open. With the carb off and empty, turn the carb upside down and back, you should hear the float drop and return.
- you mention a 'new' gas cap. The cap needs to be vented to allow fuel to flow. I purchased a cap a year or two ago and while it is purported to be vented and the vent mechanism is observed, in reality it does not vent. It does not take long for the fuel to stop and likewise the tractor.

Both adjustment screws on the carburetor should be screwed in till they stop (gently) and then backed out 1.5 turns as an initial adjustment.

I'd encourage you to persevere. I think you are very close. There is nothing associated with 'being old' which is keeping the original carburetor from working.

 

[Mad Farmer]

Fuel flow test out bowl drain first.

Did you blow out all the passages with carb cleaner and air? You should have seen the cleaner drain out connecting passages.

 

[steveTVC]

Fuel flow test out bowl drain first.

Did you blow out all the passages with carb cleaner and air? You should have seen the cleaner drain out connecting passages.

Yea I blew everything out very well. The only thing I was not sure about is the power jet, I believe it was below the long brass jet which takes a deep 3/8 socket to get out. It was so corroded I couldn't tell if there was something in there or not. I couldn't get a grip on anything in that hole so I just put the new jet from the kit in there. Once I get the fuel flowing in the bowl, I will try and crank it again.

 

[Jim L WA]

The gas cap let water into the tank? Does this tractor have a hood on it?
Vapor lock is very rare on a gravity fed fuel system, especially with a cold engine. That's not it!
Don't pay much attention to how much gas you see in the fuel bowl. Do the test that Pomester suggested and get back to us.

 

[steveTVC]

Ok I will do those tests first but yes someone at some point cut 2 holes in the hood, one at the gas cap and radiator cap. The gas cap gasket is thin and allows water to splash up into the tank. That's why my carb was in such bad shape.

 

[Jim L WA]

So, rather than raise the hood to put gas in or check the coolant, let's just cut big holes in the hood. My TO-20 has a FEL on it and I have to raise it to open the hood to add gas etc. But that's not difficult, I just have to pull on a lever.

 

[steveTVC]

The hood is a little bent and doesn't latch well probably from someone running into a stump or something. Instead of taking it off and fixing, they cut holes and inadvertently fouled up the fuel system. I have it tarped off for now until I figure out a new cap and possibly weld some patches. I am trying to get this tractor running first. Another fun fact is there was coolant in the oil when I first started looking things over. So the first thing I did was change the oil and filter. I am hoping some K-seal will fix the problem but I am guessing I will have to remove the head and replace the gasket. I want to make sure it runs before I put that kind of time into it!

 

[scootergmc]

The only thing I was not sure about is the power jet, I believe it was below the long brass jet which takes a deep 3/8 socket to get out. It was so corroded I couldn't tell if there was something in there or not. I couldn't get a grip on anything in that hole so I just put the new jet from the kit in there.

I am confused by this. You're saying you couldn't see the jet or get a grip on anything because of corrosion, so you just put a new jet in? How is that possible? Did you take the old jet out? The power jet does sit below the nozzle, but what you're saying doesn't make sense to me.

Or are you saying you just installed a new nozzle over the old power jet? If so, that happens a lot but you do have to get it all cleaned out down there, even if you can't remove the power jet.

 

[steveTVC]

Yes I didn't feel anything under the nozzle so I put the new jet down there because I assumed the power jet was missing. Possibly it was just so corroded that I couldn't even see it. Would that not allow the engine to start up without that jet? Either way I will get that carb back off and do some more digging. Possibly poke with a wire in the power jet and see if I can open it up more? Maybe I'll keep some more carb cleaner in that hole over night and try to loosen it up.

 

[scootergmc]

Yes you need to pull the bowl and remove the nozzle. If you have a can of Berryman Chem-Dip, that's what I use to soak. Otherwise you need to soak it with something. Using a long narrow pick, try to clean around the jet until you see brass. When they don't come out, I soak, clean, run a little wire, lots of compressed air, direct shots of brake clean or carb cleaner, and more air until I think it's good. I'm not sure how you could stack a jet on top of another or if there's clearance. I've never tried .

I just happen to have one I'm rebuilding all masked up for paint. I'll sacrifice my masking so you can see what's down there. You'll see screwdriver pry marks of an unsuccessful removal attempt. I left the jet because it too was stuck and all I'm going to do at that point is chew it up and it wasn't that dirty when I started. If I wanted to get it out, I could put heat to it, but usually they're ok once I do the above. Standby for pic....

 

[scootergmc]

Here you go, it's hard getting my phone to focus down there while holding a light:

 

[steveTVC]

Ok yes I used the Berryman Chem dip for days on this as well as brake clean and compressed air. I have carb cleaner coming in a couple days for when I get this back out. I think I was getting frustrated at this point because the idle jet was quite difficult as well. I think I got it quite clean otherwise