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Discussion Starter #1
I have a 425 with 1270 hours on it that up until Thursday has always run great. I was almost done mowing and it started to act like I was running out of gas. I was able to disengage PTO and lower RPMs and drive to garage. At the time gas tank was less than a 1/4 tank and the fuel filter was maybe 1/4 full. I thought maybe it was low on gas so I filled the tank. I can hear the fuel pump running when I turn the key. I can start like usual but when I increase RPMs it starts to cut run rough and dies. Sometimes this is as soon as I increase the RPMs and sometimes when I engage PTO.

I bought this unit with over 1000 hours and am not sure if the cam gear has been changed.

Where should I start looking?

Thanks
Steve
 

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You should check your tractor serial number to see if it falls within the years for the plastic cam gear. It sounds like it may be a fuel delivery problem since you state that the filter is only 1/4 full. Mine, while running, is almost completely full. The fuel pump may be going bad, or there may be a strainer on the fuel pickup inside the tank that has become partially clogged. Ethanol fuel plays havoc on fuel systems and breaks down the fuel lines from the inside out, resulting in clogged up carburetors. It is easy enough to remove the fender pan on a 4X5 unit to access the fuel tank, pump and hoses. That is where I would start.
 

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You should check your tractor serial number to see if it falls within the years for the plastic cam gear. It sounds like it may be a fuel delivery problem since you state that the filter is only 1/4 full. Mine, while running, is almost completely full. The fuel pump may be going bad, or there may be a strainer on the fuel pickup inside the tank that has become partially clogged. Ethanol fuel plays havoc on fuel systems and breaks down the fuel lines from the inside out, resulting in clogged up carburetors. It is easy enough to remove the fender pan on a 4X5 unit to access the fuel tank, pump and hoses. That is where I would start.

Definitely look into weather your engine has the plastic cam gear. Improper cam to crank shaft timing can give you signs of a fuel delivery problem. Don't ask me how I know. lol. Your engine is well above the amount of hours it usually takes to have it cause problems.

If your engine is not one with the plastic cam gear. Start looking into possible fuel delivery problems.
 

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Definitely look into weather your engine has the plastic cam gear. Improper cam to crank shaft timing can give you signs of a fuel delivery problem. Don't ask me how I know. lol. Your engine is well above the amount of hours it usually takes to have it cause problems.

If your engine is not one with the plastic cam gear. Start looking into possible fuel delivery problems.
I am pretty sure that it had one as I think it is a 1994 but I will check serials tonight. But I am not sure if it's been replaced.
Is there any way to tell without pulling it apart?

And I thought it would just stop running if the cam gear went bad. Based on your experience I see this is not true.
 

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I am pretty sure that it had one as I think it is a 1994 but I will check serials tonight. But I am not sure if it's been replaced.
Is there any way to tell without pulling it apart?

And I thought it would just stop running if the cam gear went bad. Based on your experience I see this is not true.
No other way (that I know about) except opening it up.

Weather the engine quits or not depends on the failure. The problem usually starts with the teeth wearing down or a few of them chip off. This allows the cam timing to wander around instead of being exact. Like it needs to be. If the timing jumps far enough it could also cause other internal damage.
 

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My gator has essentially the same motor and I have a UTV with the same. I have had each of them do something similar and on both it was the fuel pump. On each the pump ran but only pumped sporadically.
 

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If you have the plastic cam gear, it usually fails well before reaching 1,000 hours. Mine died at about 700 hours. While somewhat intimidating, taking the engine out and disassembling it to replace the cam is fairly easy if you are mechanically inclined. While I had mine torn down, I replaced the water pump, thermostat, oil pump and rings. I also replaced the original (old style) carb with a new, later model, one. This eliminated the hard starts and flooding issues after the engine is warm. Parts are not exactly cheap but are available from JD and it is cheaper to refresh the engine than it is to replace it with a new one.

As stated earlier, I would eliminate the far easier to repair issues (fuel system).
 

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Discussion Starter #8
Update -

The serial number shows it's a 1993 so I would guess it at least had the plastic cam, maybe it still does.

I played with it a bunch last night and the fuel filter stayed full the whole time.
I was able to get it to run at low to mid RPM but if I engage the PTO or rev the RPMs it dies.
I had it running at high RPM for 5 minutes or so but then it just died.
Sometimes when it dies, it takes a few seconds of stumbling for it to die and others it just instantly dies.
It does seem like I need to play with the choke a bit to get it restarted. It is definitely not flooding out.

I think I will pick up a fuel pump and start there.

Thanks
 

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Okay, i ordered the fuel pump today. While waiting i checked the spark and it looks like i have spark even while it is cutting out.

I had one cylinder that was a bit lower than the other but i thought that was probably due to the fact i couldn't bring it up to temp before testing.

I made a leak down tester and notice that the same cylinder had 50 % loss through the exhaust valve. I know it probably isn't related to my current problem but i now have another thing on my to do list
 

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Okay, i ordered the fuel pump today. While waiting i checked the spark and it looks like i have spark even while it is cutting out.

I had one cylinder that was a bit lower than the other but i thought that was probably due to the fact i couldn't bring it up to temp before testing.

I made a leak down tester and notice that the same cylinder had 50 % loss through the exhaust valve. I know it probably isn't related to my current problem but i now have another thing on my to do list
You can do an accurate compression test with the engine cold. Did you open the throttle blade all the way while doing the test? After the first reading put a few squirts of motor oil into the cylinders and run a second test. See if the reading gos up. If it does it's a ring problem.

Also 50% leak down is a major problem. This will definitely cause running problems. I assume that you hear air escaping into the exhaust system. Pull the valve cover on the problem cylinder. Make sure that the exhaust valve is not hanging open. Like the adjustment on the rocker arm is to tight.

This is another thing that you can try to check the cam timing without opening the whole engine. Remove both valve covers and spark plugs. Turn the engine over by hand. You are trying to see if the engine is out of time. Touch the top of the pistons with a small wooden dowel. Watch how the rocker arms react in relationship to the pistons moving up and down. Every few degrees of rotation turn the crank backwards. You are looking for a spot or spots where the valve train is not moving correctly in relation to the crank shaft. If you can move the crank a large number of degrees without moving the rocker arms you found a problem.

Good luck
 

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425 running rough

You can do an accurate compression test with the engine cold. Did you open the throttle blade all the way while doing the test? After the first reading put a few squirts of motor oil into the cylinders and run a second test. See if the reading gos up. If it does it's a ring problem.

Also 50% leak down is a major problem. This will definitely cause running problems. I assume that you hear air escaping into the exhaust system. Pull the valve cover on the problem cylinder. Make sure that the exhaust valve is not hanging open. Like the adjustment on the rocker arm is to tight.

This is another thing that you can try to check the cam timing without opening the whole engine. Remove both valve covers and spark plugs. Turn the engine over by hand. You are trying to see if the engine is out of time. Touch the top of the pistons with a small wooden dowel. Watch how the rocker arms react in relationship to the pistons moving up and down. Every few degrees of rotation turn the crank backwards. You are looking for a spot or spots where the valve train is not moving correctly in relation to the crank shaft. If you can move the crank a large number of degrees without moving the rocker arms you found a problem.

Good luck
Try the TDM (time delay module). That caused me grief in the past.

Good Luck
 

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The job list keeps growing

I checked the valve lash last night and if anything the gap was too large, not holding the valve open. I am going to redo the valves. And since I had to pull the head and intake and carb, I decided to rebuild the carb, change the cam gear(full kit with cam, valve springs, governor and waterpump) also since cheap and easy the TDM.

This is adding up quick!
 

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I would of started with some seafoam and gone from there, that stuff seems to do magic when I have what appears to be a fuel starving problem. JM2C
 

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Probably a wise course of action if indeed you have the plastic cam gear. At 1,000 hours, it is on borrowed time. Waiting for it to completely fail could cause serious, collateral, damage. The Kawasaki engine is relatively easy to work on. If you can work on a Kohler, Briggs, etc. it is no big deal. I would go ahead and check everything else inside the engine while you have it down. No sense in having to tear it down twice. Lots of experience/help available on this site if you run in to something you are not familiar with.
 

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Don't overlook that the fuel pump has a fuse under your dash that should be checked. These tractors will run with a bad fuel pump, they just won't run correctly.

Be careful when you position the fuel pump in the tank to make sure that the fuel gauge float doesn't get hung up on the side of the tank. If this happens the fuel gauge will not function correctly and may lock into one place once the float become stuck.

You can can tell by looking down in the tank when you have it opened up where the big nut around the tank flange is removed to get the fuel pump out. Also, very important Make sure to use a NEW O RING in the re assembly of the new fuel pump or it will leak around the flange nut. Be careful not to cross thread the large plastic nut which holds the fuel pump in place on the tank assembly. This only needs to be hand tight (arm strong tight).

Also, make sure to carefully position the in tank filters. My money is on the fuel pump and possibly either the in tank filter or an in line filter causing your issue. These pumps are known to go bad. I have replace two of them on my own tractor over the years.

Don't forget to check the air filter canister and the inner and outer filters. If the tractor can't get enough fresh air, it will stumble and run rough not to mention dramatically increase the engine operating temperature because of the fuel ratio being off and the tractor struggling to take enough air in to run right.

The other thing I have seen repeatedly is that the debris under the rear platform (where the seat sits on the body over the rear end and tires, etc) actually will cause the rubber fuel lines to be compressed restricting fuel flow. Debris builds up over time and when you are bouncing around on the seat. the fuel lines will shift around under the platform on top of the fuel tank.

Carefully check the fuel lines (both of them, the supply and the return) to make sure the lines are not internally collapsed. The ethanol fuel will plug up the fuel lines with a sugary looking substance from the corn decomposition. If nothing else, disconnect each end of the fuel lines and blow some compressed air through them to make sure the fuel flows easily and does not have debris in them. Just don't blow air through the fuel pump or any filters, etc. as it can damage them.
 

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You can inspect the cam by pulling the water pump. Then you can see a small portion of the cam. Then rotate engine by hand to look at another section of the cam. Rotate, repeat.

If I were a betting man, I'd say it's the cam. Ignition module is usually heat related, not load. You can check the fuel pump by pulling the hose off the carburetor while ignition is on. I wouldn't run it until confirming it is or is not the cam.
 

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Discussion Starter #17
Update

i took the engine apart to take check the camshaft. I did have the plastic cam gear. it was still in good condition for 1300 hours and the timing marks were still aligned.

I got the cam kit, fuel pump,carb kit and TDM last week. I rebuilt the carb. and reseated the valves then put everything back together. Have not done fuel pump or TDM yet. Fired her up last night and made some adjustments to the carb. WOW, is all I can say so far. It is idling so smooth and seems to be able to run until I shut it down. Original problem may have been crud in carb.

I do have a leak coming from the carburator but I think it might be a stuck float. Easy fix I hope.

Also need to adjust RPM and Fast idle adjustments yet and I will replace the TDM and Fuel pump.

Getting excited to use it again.

Thanks for all your help!
 

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i took the engine apart to take check the camshaft. I did have the plastic cam gear. it was still in good condition for 1300 hours and the timing marks were still aligned.

I got the cam kit, fuel pump,carb kit and TDM last week. I rebuilt the carb. and reseated the valves then put everything back together. Have not done fuel pump or TDM yet. Fired her up last night and made some adjustments to the carb. WOW, is all I can say so far. It is idling so smooth and seems to be able to run until I shut it down. Original problem may have been crud in carb.

I do have a leak coming from the carburator but I think it might be a stuck float. Easy fix I hope.

Also need to adjust RPM and Fast idle adjustments yet and I will replace the TDM and Fuel pump.

Getting excited to use it again.

Thanks for all your help!
Well at least now you have piece of mind about the inside of your engine. You dont have to worry anymore if and when something bad will happen.
 
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