Need diesel help - John Deere 332 tractor

[rfuerst911sc]

So about two months ago my JD 332 garden tractor started running rough after about 15-20 minutes of mowing . Will start easily cold and run great for that 15-20 minutes .

Last week I replaced the fuel filter by the engine . No change . Today I pulled the fuel tank , cleaned it and reinstalled . Installed a new in tank tygon fuel line and in tank filter . Also installed two new rubber bushings in the tank where the fuel lines enter and exit .

Ran new fuel line from the tank to the fuel pump and fuel pump to engine fuel filter . Bled the fuel filter housing until a solid flow of diesel came out . Put it all back together , lit the glow plugs and fired her up . She started immediately and idled great . Let it warm up for a few minutes and started mowing .

Again about 15-20 minutes later she started to lose power , like it's running out of fuel . I am stumped at the moment on what to do next . Any ideas ? Tractor has about 1500 hours but has run like a top for years with no issues . It's so weird that it starts and runs perfect then it doesn't .

[oldE]

Sounds like you are pulling a vacuum.
Check the cap for proper venting.

Best
Les

[rfuerst911sc]

Originally Posted by oldE

Sounds like you are pulling a vacuum.
Check the cap for proper venting.

Best
Les

I will try unscrewing the cap . But the fuel tank filler neck has an overflow elbow/hose that I would think would let the tank breathe . But thanks for the suggestion .

[Scott Douglas]

That overflow elbow/hose will work until some spider builds a nest in it.

[asphaltgambler]

Sounds like the transfer pump is failing after running fir a while. If it is original, just replace it.

[rfuerst911sc]

Originally Posted by asphaltgambler

Sounds like the transfer pump is failing after running fir a while. If it is original, just replace it.

I know it's not the original as it is wired in with wire nuts ☹️ . But it definitely could be failing .

[oldE]

So, any progress?

Best
Les

[rfuerst911sc]

Originally Posted by oldE

So, any progress?

Best
Les

Not yet been busy with other things . Grandchildren have soccer games today but I hope by end of day tomorrow to have completed more analysis . I will update with results .

[oldE]

The next time you're operating the tractor and it starts to lose power, loosen the fuel cap before it stalls to see if that allows it to pick up its fuel.

Good luck.
Les

[rfuerst911sc]

This morning I finally had a chance to work on the tractor . First I checked battery voltage it was 11.70 at rest . Not good . But it's enough to lite the glow plugs and engage the fuel shut off and PTO . I noted that the fuel shut off when energized is fully pulled back meaning I couldn't move it any further with my hands .

Battery voltage with tractor running is 11 .70 so obviously I have an issue with the alternator/voltage regulator . But I pressed forward and started mowing . True to form started running rough after 15-20 minutes .

I completely unscrewed the fuel filler cap with no change in performance . I checked the fuel shut off it was still fully retracted . So I don't think my issue is vacuum related or defective fuel solenoid .

I touched the electric fuel pump with bare hand and it was VERY hot , to the point I couldn't keep my hand on it . It is on the tractor frame with about 2" of air gap to the engine . I would expect it to get warm from radiant engine heat but not hot . So my next step is I am going to order a new fuel pump .

I need this running for fall cleanup and final mowing . Over the winter I plan new water pump , thermostat and alternator belt . I have an excellent local guy that repairs alternators and starters so will have him go through it. That's it for now .

[oldE]

Sounds like you found the culprit. Good work!

Best
Les

[rfuerst911sc]

Originally Posted by oldE

Sounds like you found the culprit. Good work!

Best
Les

Too early to claim victory but I feel good so far . I just ordered a new pump should have it in two days . Will update after it's installed .

[Scott Douglas]

Vapor locking in a diesel, that's gotta be a first.

[rfuerst911sc]

I am guessing that the fuel pump is running hot because it is partially clogged or defective . Installing a new pump will prove the theory . I will be stumped if a new pump doesn't correct the issue .

[rfuerst911sc]

Installed the new lift pump this morning . Hooked up the battery charger as it barely turned the engine over . Two hours later I bled the system and she fired right up .

Mowed for 35 minutes and she started running out of power ☹️ . I touched the new fuel pump and it was just as hot as the old one . I am currently stumped on what to check next .

[Gretch]

does sound like fuel starvation................ "power down" can also be dirty air cleaner, but that doesn't generally make them run rough............. fuel filter? crimped fuel line?

[rfuerst911sc]

Everything from the fuel tank to the fuel filter housing is brand new . Fuel filter is brand new . Fuel tank has been cleaned . I will check the air filter next .

[asphaltgambler]

I think you're overlooking the charging / battery issue. If the alternator is not charging the battery and /or the battery is sulfated - the operating voltage could be dropping below the fuel solenoid shut-off rating. In other words, there is not enough running voltage to keep the fuel solenoid "on" as you're mowing.

[rfuerst911sc]

That is an excellent theory but when it starts losing power I check the fuel shut off solenoid and it is pulled all the way back . That is the open position. I can't manually pull it back any further. And the electric PTO stays engaged .

But I need to check to make sure the solenoid linkage is tight , just thought of that . If the linkage is creeping towards closed it doesn't matter if the solenoid is pulled back .

I keep this tractor in a carport. I need to make sure verman or bugs haven't built a nest or obstruction in the air filter cylinder .

[asphaltgambler]

Good, keep us posted!