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Discussion Starter · #1 ·
My 332 started running rough after 15-20 minutes of mowing . This started out of the blue about two months ago . It starts immediately and runs great up to the point of running rough . To me it feels like running low on fuel as it slowly loses power .

Today I pulled the fuel tank and drained it . The fuel pickup hose was missing and the filter was in the tank . Cleaned tank with mineral spirits it came out clear . Installed new tygon fuel hose and new filter in the tank . Installed two new rubber bushings .

Installed new 5/16 fuel hose from tank to fuel pump and fuel pump to engine fuel filter housing . I had installed a new fuel filter last week . I opened the bleeder screw on the filter housing and let diesel pour out until it was a steady stream .

Put the fender deck back on and turned on the glow plugs . Then hit the starter and she fired up immediately and settled into a steady idle . Let it warm up for 5 minutes and started mowing . Again after 15-20 minutes of mowing she starts slowly losing power and I had to shut off the PTO . I am stumped . Help please
 

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Well, it could be many things that cause that noticeable loss of power. Have you verified that the tank is getting vented properly and not pulling a slight vacuum as fuel is getting used? If it really is run time and/or heat related, have you tested the lift pump output when the failure is happening? What about engine compression? You need a special tool for the diesel due to high pressures, but knowing is going to eliminate that as a potential cause. Are you sure the intake and exhaust valve clearances are within spec?

Maybe other members have additional things to check...

Chuck
 

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Discussion Starter · #3 ·
I thought about the fuel cap possibly causing a vacuum and will unscrew it to see if that helps . But there also is an overflow tube as part of the filler neck that I would think would allow the tank to breathe .

I have not checked fuel pump output or compression or valve clearance . I don't have a compression tester for a diesel . I am wondering if the fuel shut off is losing power with the PTO engaged . I may wire it open with a zip tie to see if that does anything . I will also check alternator output .
 

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Another test may be to place a zip tie on the fuel shutoff solenoid to hold it open after you start it. If the hold portion of the coil is getting weak I could see it slowly closing when it get warm. You'll need to cut the zip tie to shut it off.
 

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Good advice so far.
Before zip tieing the fuel solenoid open, remove the pin from the arm. Push the arm to allow fuel and see where it stops. Then check adjustment on shut off solenoid linkage. It needs to move as far as the arm did. Pull the boot back and check for rust in there, read of them binding.

Google up the manuels,
TM1591 for tractor,
CTM3 for engine.

After rereading your 1st post, check the lift pump out. With your fuel pickup being broken, you were sucking air in. That may have burnt that pump. Check that pump cold, then again when it's hot enough and acting up. Diesels dont play well with aerated fuel, lol.
 

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I agree with Chuck. Check the tank vent. You really have done what I would have done for sure. The things you did would have been the first things to do.
But Chuck is correct also with the lift pump. (electric or manual) either one can go bad and pump for 15 mins then stop working.
 

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Just check to make sure 1 of the vents is clear.
 

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Put a piece of clear line between the filter housing and the injector pump. Look for air bubbles. My 332 was doing this exact thing a few years back. I ran through all the above, plus rodding the radiator, and more. It turned out, the filter housing was sucking in air via one of the bleeder screws. No amount of tightening or crush washer swapping fixed it. It needed a new housing. How it was purging the air on its own and running good for a half hour, I don’t know. But it sure was.
 

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Discussion Starter · #12 ·
Installed a new lift pump this morning . Bled the system and she fired right up . Mowed for 35 minutes and she did the same thing as before ☹ . I guess I will install a clear line between filter housing and injector pump to see if the filter housing is introducing air bubbles . Very frustrated at the moment .
 

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Mowed for 35 minutes and she did the same thing as before
Yep that’s exactly what mine did. Same symptoms too. Sputtering and sluggish and down on power. That clear line will tell you if there’s air infiltration before the IP. It don’t take much air to make it run like hell, either. It’ll leak a small amount of diesel when it’s not running and you’ll see it evidences by a fine dusty greasy coating by the leak.
 

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Discussion Starter · #14 ·
Today I replaced the air filter with a cleaned used one. The one I removed didn't look bad . Then decided to see if the fuel bowl mounting ring was tight . With channel locks was able to turn it a good 1/3-1/2 . I really thought this would fix it , sadly it didn't . Same runs great for 30 minutes then starts running rough and low on power .

I will have to get some clear hose for the filter housing to injector pump . If that doesn't show air bubbles I am probably going to sell as is or trade it in .
 

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Positive it isn't overheating? It can have similar symptoms while overheating. If you open the hood all the way while running it will cool down quite fast. Maybe worth a go next time you mow.

Sent from my SM-G781V using Tapatalk
 
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^^^^ I can only say there are no lights on the dash that indicate an overheat condition .
For all that it's worth, I'd check that the light works by the following:
  • Disconnect the wire from the coolant temp switch, turn the ignition key on, and ground the wire. The coolant light should come on.
  • Reconnect the coolant temp switch wire. If the tractor's safety interlocks are still active, disable the engine crank circuit; by either moving the ground speed control lever away from Neutral/Stop, or turn on PTO switch. Turn the ignition key to "Start." The coolant temp light should come on while you have the key in the "start" position.
These tests will confirm the circuitry is working for the light. The only way to test the switch itself is to heat it up to 225-235F (107-113C), and check continuity. When the temperature reaches the aforementioned range, the switch close the circuit, providing ground for the coolant temperature light so it will illuminate.

Alternatively, you could toss a coolant temp gauge into it, or rough check with an IR gun on the thermostat housing/radiator inlet. If you have a thermocouple reader, install a thermocouple in place of the coolant temperature switch bolt for measurement.

The only other things would be thermostat not fully stroking open (minimum spec 6mm at 85C), or excessive buildup on the air inlet screens (pedestal or belly screen or both), radiator screen, or in the fins.

Don't get discouraged, the issue is overwhelmingly likely to be a relatively simple/inexpensive fix.
 

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Discussion Starter · #19 ·
This morning I decided to pull the right engine cover to look at the voltage regulator . What a mess ! Fried wires and the back of the VR about half of the potting material is burnt and blown out 😡 .

So I have to replace the VR and correct/repair damaged wires . No clue if the alternator is fried or not . Not sure if this will help or correct my running issue but it can't be helping .
 

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The vr and wires being melted is a common issue. My 332 did it 1.5 years ago, cooked the water right out of the battery.
Good news is at least it's relatively easy to repair and theres a relay that can be installed to prevent overcharging.
If your interested in installing the overcharge relay, contact chuckv on here. He has a very nice schematic he made showing the wiring.
 
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