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Discussion Starter · #1 ·
Hello, I have a JD 425 with a Kawasaki engine. The tractor model number is M00425A032435 and i cant find a number on the engine but after researching I think I have found it is a FD620D Engine. My problem is the engine will not without the choke about half on. Now sometimes it will run fine for a few minutes and then it just shuts down and I have to apply about 1/2 choke and it tries to run but it either floods or starves for gas. Have cleaned the Carb several times and it is clean, have ultrasonic cleaner i ran it through as well as hand clean with now difference. I also changed the delay stop switch that my JD shop said that was the problem, wasn't. We are out of options the mechanics at JD dealer don't know and I am at my wits end. The carb does not have Electrical fuel cutoff on it so I do not believe it is electrical. As long as I spray carb cleaner in carburetor the engine will run fine but when I stop it goes back to starving for fuel. Engine compression is fine and Valves are adjusted to correct gap. ANY IDEAS PLEASE HELP.
 

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I guess I would start by finding out if it's actually flooding or starving for fuel. Run it till it dies then pull both plugs, check to see if the plugs are wet or dry. If ithey are wet u know its flooding if ither dry then it's probably starving for fuel. Then u can proceed with trouble shooting in the correct direction.
 

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Hello, I have a JD 425 with a Kawasaki engine. The tractor model number is M00425A032435 and i cant find a number on the engine but after researching I think I have found it is a FD620D Engine. My problem is the engine will not without the choke about half on. Now sometimes it will run fine for a few minutes and then it just shuts down and I have to apply about 1/2 choke and it tries to run but it either floods or starves for gas. Have cleaned the Carb several times and it is clean, have ultrasonic cleaner i ran it through as well as hand clean with now difference. I also changed the delay stop switch that my JD shop said that was the problem, wasn't. We are out of options the mechanics at JD dealer don't know and I am at my wits end. The carb does not have Electrical fuel cutoff on it so I do not believe it is electrical. As long as I spray carb cleaner in carburetor the engine will run fine but when I stop it goes back to starving for fuel. Engine compression is fine and Valves are adjusted to correct gap. ANY IDEAS PLEASE HELP.
Sounds like it's starving for fuel. Using the choke partially closed allows you to supplement the idle & main fuel circuits with unmetered fuel. You may have dirt or debris clogging an idle or main jet. Sometimes you need to use a wire gauge jet cleaning tool to open the passages. I've encountered this with small engine, motorcycle and snowmobile carburetors in the past. Solvent won't always open these very small passages.

Here's what I use: BikeMaster Carburetor Jet Cleaning Tools 152212 - Free Shipping on Orders Over $99 at PowerSports Place

Take it apart once again and mechanically clean all of the fuel and air bleed passages and you should be OK.

Frank
 
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Discussion Starter · #4 ·
425 carb problems,

Thanks Frank I ran jet cleaning tools through all the jets after removing them, they are all open and clean I find only 4 jets in the carb. one in the bottom for fuel intake one in the top for fuel flow and two very small ones in top that I believe are air. it has to be starving for fuel as I said I can spray carb cleaner while its running and it will smooth out as long as I spray a small stream in the carb, soon as I stop engine dies and I have to pull choke for it to run but it runs really rough. Fuel pump is working fine, good pressure. Like I said sometimes the thing runs great for several minutes and then stalls. It will start back up but has to have choke on then to run. Been through the carburetor numerous times and I really believe it is clean. Im about ready to purchase a new carburetor but they are really expensive trying to be sure it is the carb before making that investment. I just do not know what else it can be. Any further Ideas?????

Sounds like it's starving for fuel. Using the choke partially closed allows you to supplement the idle & main fuel circuits with unmetered fuel. You may have dirt or debris clogging an idle or main jet. Sometimes you need to use a wire gauge jet cleaning tool to open the passages. I've encountered this with small engine, motorcycle and snowmobile carburetors in the past. Solvent won;t always open these very small passages.

Here's what I use: BikeMaster Carburetor Jet Cleaning Tools 152212 - Free Shipping on Orders Over $99 at PowerSports Place

Take it apart once again and mechanically clean all of the fuel and air bleed passages and you should be OK.

Frank
 

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If it's running poorly and you were to stop the engine and take to top off the carb the float bowl should be filled with gasolene. Remote possibility is the float isn't dropping sufficiently to allow the bowl to completely fill. Did you check and set the float drop and height settings?
 

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Just throwing this out there - if it's starving for fuel have you checked that the air vent in the gas cap is clear? Does loosening the gas cap let it keep running?

I may be totally off with this suggestion being that you need 1/2 choke to keep it running.
 

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Another idea

Checking the gas cap is a good one. But, before you go out buying anything, consider this. On any equipment with naturally aspirated engines, running with the choke out almost always means an air leak somewhere in the intake train. What happens is that the air leak creates a lean situation, and the engine can't run that lean. The choke makes up for the lean condition, and, wha la, the engine runs. I have seen this happen on numerous tractors. Suggest that you investigate the possibility of an air leak somewhere in the intake system, including a bad carb gasket.
 

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Discussion Starter · #9 ·
425 carb problems,

Removing the gas cap does not help, again fuel pump works fine with no leaks. I am going to pull it down again and check for air leaks in the manifold. when it quits I removed the top of the carburetor and the bowl is full of fuel. :dunno:
 

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Fuel filter changed?

You could try setting up a temporary fuel supply and run a line from it to your fuel pump to take the gas tank out of the equation and see if the problem goes away.
 

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Replace the fuel hose from the tank all the way to the carb and drain the fuel tank. My LX176 was doing the very same thing and I tried everything under the sun until I struck gold with the hose. Also might want to consider getting gas from a different place to see what happens.
 

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Fuel filter changed?

You could try setting up a temporary fuel supply and run a line from it to your fuel pump to take the gas tank out of the equation and see if the problem goes away.
Yep. Hoses are cheapest and easiest to try. I've also read reports where fuel pump was working but a crack in the nipple just at exit was causing it to draw air. A crack in a hose will do the same thing and may not leak fluid.

Those carbs are bullet proof. Messing with it would be the last thing I'd try. I never, ever adjusted or repaired mine in nearly 20 years of use. Ran perfectly when I sold it. Started on first click just like when new.
 

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Discussion Starter · #14 ·
425 will only run with choke on

Well folks still no luck on this one engine will Idle just fine but as soon as you try an throttle up it dies unless i apply choke then it tries to run but surges with the choke on. Now sometime it floods and i take the choke off and it dies again until choke is applied. I have reset valves, been through carb a dozen times, fuel pump is working fine, I even put another fuel pump with another tank. Carb bowl is staying full. changed the intake manifold gaskets, carb gaskets, new fuel, plugs, remoned fuel tank cap. About to pull heads unless some one has a Idea on this crazy thing. Oh also replaced the kill delay switch. Any one with Ideas, I have done this for 30+ years and this engine has me stumped. I will appreciate any help, customer need his mower. Thanks
 

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Based on the serial number, it's a 95. Have you looked up the carb adjustment procedure in the technical manual? I think that this model has the same solenoid as mine which is a simple pintle that pulls out to open the carb for fuel. There is a copper gasket that provides an electrical path as well as the proper spacing for the solenoid to operate. Is it there and in good condition? What about the throttle butterfly shaft bores? Are they badly worn? How about the carb base? Maybe it's warped.

Have you tried using an unlit propane torch to search for a vacuum leak?
 

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I used another fuel pump with direct line from another tank no change, i have ordered a carb kit for the intake gasket. I have to be getting air from somewhere.
If you had an air leak the engine wouldn't idle. The fact that it will idle rules that out. You probably have a blocked high speed circuit in the carb.
 

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I agree with techie. As I understand the fuel solenoid, it might not shut off the fuel 100% as it hammers inside the carburetor. As I was working on Dad's 1997, I thought it was gummed up and not moving all that it should. So I replaced it not knowing surely if it was the issue, it never messed up since.
 
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