6x4 Gator Diesel surges

[ndblackhawk]

In June 2005 I bought a 2003 John Deere 6x4 Gator Diesel, the Gator had only 19 hours on it. When I got it home I noticed the motor surged while idling and throughout most of the RPM range. I called my Diesel mechanic and he told me to run an additive that John Deere reccomends through several tankfuls of fuel before I do anything else and if that doesn't fix it to bring it in. I put 70 hours on the Gator with the additive and it still surges as bad as ever, it surges just sitting in the driveway idling as well as when driving wide open. My Diesel Mechanic has had the Gator for the past 2 weeks and can't figure out what's wrong. I was told that there was a bulletin released about this problem but my John Deere dealer can't seem to find it, he did find a bulletin about surging on rough terrain but that's not the problem. I would really appreciate some help from you all. Thank you very much in advance.

 

[JESSE1]

I had the same problem with an '01 6x4 Diesel Gator. The shop worked on it several times but finally decided it was in the injector pump. Since it was still new, Deere approved replacing the entire engine instead of just the pump. Never had any problems with the replacement engine. I believe you'll find the problem is in the injector pump.

 

[joecdeere]

Here's one that may bare looking into........

Solution Number: 61166

Solution Summary: SIB 03-11-50-9 Diesel Engine Surges or Hunts At Low To Mid-Range Speed – 6x4, Trail, Worksite and Military Diesel Gators

Publication Date: Oct 1 2003

**Paper copies of solutions may not be the most current solutions**

03-11-50-9 (Linked to Pathways)

1 October 2003

DIESEL ENGINE SURGES OR HUNTS AT LOW TO MID-RANGE SPEED

6x4, Trail, Worksite and Military Diesel Gators



Complaint or Symptom:

Engine surges at slow to mid-range. Surge is usually worse in cool ambient temperatures and rarely improves when engine warms to operating temperature. Variations between 30-60 rpm are noticed when engine rpm’s are monitored with a handheld digital tachometer or a digital pulse tachometer.

Situation:

Internal governor components may be worn, out of tolerance, misaligned, or governor spring may not be calibrated correctly.

NOTE: Almost all internal governor components are non-serviceable due to EPA-CARB certification requirements.

Solution:

IMPORTANT: Do not replace engine for diesel surging complaint!

1. Isolate engine by removing the drive belts, drive clutch, and throttle cable.

2. Set slow idle speed to 1000 rpm’s ± 50 rpm’s using Handheld Digital Tachometer (JT05719) or Digital Pulse Tachometer (JT07270).

3. Attempt to duplicate engine surge throughout all speed ranges. Rapidly increase engine rpm by manually pulling on the throttle lever and holding in one position and note if surge is present.

4. If engine surge disappears, idle speed may have contributed to surge. Check condition of drive clutch and/or belt prior to re-installation.

5. If surge continues, locate Yanmar’s engine serial number located on engine plate.

6. For engines marked (-CH3007D056152) reference DTAC solution 34017 or Service Information Bulletin 03-11-50-8. Replace internal governor spring with new blue painted spring (M810473).

If engine continues to surge proceed to step 7.

7. Verify fuel source by running engine using a remote tank with fresh diesel fuel. Adding a cetane booster may increase diesel engine performance. Two popular and readily available brands are Amsoil Cetane Boost Additive® and Power Service Diesel Fuel Supplement®.

8. Attempt to duplicate engine surge throughout all speed ranges. Rapidly increase engine rpm by manually pulling on the throttle lever and holding in one position. Note if surge is present.

If engine continues to surge proceed to step 9.

9. Disconnect and remove fuel shutoff solenoid.

10. Remove four nuts (A), throttle linkage bracket (B), and gasket.

NOTE: Washer may be fixed to linkage. Do not drop pin during removal.

11. Remove pin (C) and washer (D) to disconnect governor linkage (E).

12. Remove throttle return spring and dipstick tube.

13. Remove five cap screws securing governor housing to engine.

14. Remove governor housing and gasket.

15. Remove governor spring (F) (M810473).

16. Remove cap screw (G) and governor shaft retaining plate (H).

IMPORTANT: Do not lose governor shaft shims (K). Note their location for re-assembly purposes.

17. Remove governor shaft (I), governor linkage assembly (J), and shims (K).

18. Remove small spring (L) from governor linkage assembly.

19. Remove e-clip (M) securing shifter (N) to governor lever (O). Do not lose compression spring (P) when removing and replacing shifter.

IMPORTANT: Do not damage face of shifter (N) or surging will result.

20. Remove shifter (N) from governor lever (O). This is an interference fit and may require a small brass punch.

21. Insert new roll pin (M801857) in new shifter and install shifter into governor lever. Reassemble governor linkage in reverse order.

22. Install new throttle linkage bracket gasket (M805695) and reassembly components.

23. Test engine for surge.

Field testing determined the most effective and efficient resolution for non-fuel related surging diesel engines was to replace the shifter (M806914). This eliminates surging complaints due to better alignment of internal governor components.

Additional Information:

· Do not replace engine for diesel surging complaint.

· If internal governor spring is replaced on engines marked ( - CH3007D056152) the governor assembly and injection pump must be sent out to an ADS station to be recalibrated. Reference Service Information Bulletin 03-11-05-5. Slow and fast idle speeds need to be adjusted. Reference TM1518.

· In addition to better shifter alignment, engines beginning with serial number CH3007D064255 have additional improved internal governor component alignment. Changes include a machined mounting surface on the housing, better alignment between the tension lever and pump rack, and larger radius in governor spring slot.

· Governor assemblies rebuilt using latest re-designed parts are available, however, dealers must create a DTAC case with model and engine serial. DTAC to confirm eligibility. Dealers will be required to send governor and pump directly to Yanmar America to exchange for assemblies with updated parts.

Parts: Spring
(1)
M810473
Internal Governor

Shifter
(1)
M806914


Roll Pin
(1)
M801857


Snap Ring
(1)
40M7088


Gasket
(1)
M805704
Governor Case

Gasket
(1)
M805695
Throttle Linkage

Pin
(1)
M800051

6X4DTrail, 6X4W, 6X4M, 6X4D