Kubota WG750 only runs on full choke

This isn't exactly heavy equipment... Looking at a Woods 6250 Mow'n Machine for my dad. It's very similar to my 6215 except it has a Kubota gasoline engine instead of diesel engine. Anyway, it will only run on full choke. Even just barely pushing the choke in and it dies. We cleaned out the gas tank, cleaned the carb, checked compression, checked the spark plug gaps, and checked lift pump flow. I am not very good with gas engines so I don't know what to do next, except try a whole new carb. Which makes me wonder if it even has the correct carb on it. I can't seem to find a diagram that shows what the correct carb part number is. The seller is a bit of a cob jobber so it wouldn't surprise me if he had a different carb that fit and put it on this engine. And ideas?

How did you clean the carb? Chem-dip and some spray, or actually run some tip cleaners through the jet holes? You definitely have a blockage causing a lean condition.

One thing worth checkin on the WG750 specifically, the throttle shaft bushings are a known weak spot, they wear and pull air past the shaft, mimics a dirty pilot circuit exactly. Spray some carb cleaner around the shaft while it's idlin on choke, if RPMs jump you found your leak. If the carb does turn out to be wrong or junk, post the numbers stamped on the body, parts for these are pretty easy to source.

MarshallPowerGen said: How did you clean the carb? Chem-dip and some spray, or actually run some tip cleaners through the jet holes? You definitely have a blockage causing a lean condition. Click to expand... Yeah I just used spray can carb cleaner and compressed air. The carb was surprisingly clean but I guess I need to check the jet orifices and float valve inlet passage again.

I will check that, thanks. DustAndRay said: One thing worth checkin on the WG750 specifically, the throttle shaft bushings are a known weak spot, they wear and pull air past the shaft, mimics a dirty pilot circuit exactly. Spray some carb cleaner around the shaft while it's idlin on choke, if RPMs jump you found your leak. If the carb does turn out to be wrong or junk, post the numbers stamped on the body, parts for these are pretty easy to source. Click to expand...

Ok I just pulled it apart and checked everything I could think of. First, these are the only markings I can find on it: The inlet from the fuel pump flows freely, the main jet is clear and I can see that the hole is clean by looking through it at a light. Unfortunately someone wasn't careful with a screwdriver and marred the first digit on the main jet. I have no idea if this is the correct jet.

The only thing I can't test because I don't have anything small enough is this smaller jet (I don't know what it's called): Edit: I was able to test it by putting a little soapy water on it and observing bubbles when I blew some air through it.

What should the resistance of the fuel shutoff solenoid be? I'm getting about 48 ohms. I was expecting a lot less, maybe 4 or so.

Ok, I may have solved the problem. I think the fuel shutoff solenoid wasn't fully opening, either because it was a little dirty and/or not getting sufficient voltage. The battery that was on the mower is pretty much toast so I swapped in a good battery and fixed some questionable wiring, and cleaned the plunger. Now it clicks nicely when 12v is applied. And it idles nicely with no choke. Tomorrow when it's done raining I will test it out in some thick grass and see what it does.

So you know--Keihin has been in the business building carbs for eons. Parts shouldn't be a issue if you ever need.

Truck Shop said: So you know--Keihin has been in the business building carbs for eons. Parts shouldn't be a issue if you ever need. Click to expand... Good to know, thanks.

Running only with full choke usually means it is running too lean. Since you already cleaned the tank and carb, I would check a few things before replacing parts: Make sure the main jet and emulsion tube are completely clear. A carb can look clean but still have a restricted fuel passage. Check for an air leak at the carb gasket or intake area. Verify the carburetor part number matches the Kubota engine. A carb that fits physically may still have incorrect jetting. I would also check the throttle/governor linkage to make sure it is opening correctly. If you can provide the Kubota engine model number, it may help confirm the correct carb setup.

@Wishope , can you hold 3 fingers in front of your face for me?

Keihin makes a lot of carbs. for motorcycles. I think Honda might be affiliated with Keihin.

The fuel shutoff solenoid seems to have been the problem. It's running well with good power now.