Any John Deere gator Tech's on here???

PPosey

PPosey

Twelve Pointer
My 2000 gator 6x4 diesel is giving me fits,, Lack of power on a hill,, I have replaced both clutches and the fuel filter,, were it a gas motor I would be more at home but the diesel is out of my experience, anybody have experience with these things?

It has been having issues for months,, sometimes when starting it it would lack power then restarting it, it would run better.

A few weeks ago the primary clutch locked up and I replaced both clutches and belt. Since then the power has been lacking,
 
PPosey

PPosey

Twelve Pointer
That depends 700 or so on the machine and 200 or so on the motor,, the machine CAME WITH A YANMAR 3TN66 MOTOR AND WE REPLACED IT WITH A 3TN68, as the 66 was ruined by a previous owner,,, sorry caps lock came on.

The 3tn68 ran great for 3 years
 
blazinbowtie99

blazinbowtie99

Six Pointer
No Deere tech but we deal with diesels at my office. Check your air filter too. See if that little engine has a mechanical or electric fuel lift pump. Also, any joints/fittings where fuel lines or hoses hook up, check for debris. Also, may want to blow a little light pressure air back thru fuel tank and make sure something isn't in the tank plugging up pick up.
 
PPosey

PPosey

Twelve Pointer
Fuel intake is clear, there is a manual prime lever on the bottom of the pump and it works well, used it when I changed the filter, every push on the lever pulled fuel into the filter reservoir, also manually inspected the fuel intake and it is clear, tried it with the outer air filter removed and there was no difference, inner filter looks new. Will check more lines after I get the bed pulled
 
JoeR

JoeR

Eight Pointer
If it did it right after you changed the clutch, then my bet is that is the problem. Is the drive belt even with the top of the driven pulley when it is sitting still? The outside surface of the belt should be level with the outer edge of the driven pulley. If it sits down too low you need to fix that first. get the correct diameter belt or shim the driven pulley.
Is the belt too long? Either of those problems will cause it to have low power, just like you are in too high of a gear.
It can also act like that if the clutches don't have the correct weights and springs in them. Is it an OEM replacement clutch?

Joe
 
PPosey

PPosey

Twelve Pointer
both clutches are OEM as is the belt,,, they seem to be the correct ones and the belt sets correctly,,,
 
JoeR

JoeR

Eight Pointer
Diagnosing stuff at a distance is not a perfect process, but here'd be my next move. Diesels with mechanical injection pumps will normally huff a little black smoke at full load. Did you notice yours doing this? If it did before, and it's not doing it now, then it could point to a lack of fuel. If it's making black smoke then the fueling is probably fine. The only exception to this would be if the engine is running unevenly or rough. Then all bets on smoke diagnostics are off. When it has a lack of power does the engine run rough or dies it just feel like you're not pushing the throttle down?
Joe
 
PPosey

PPosey

Twelve Pointer
AS to the smoke I have no Idea, the exhaust is so far back on the gator that I have not noticed but I can try it this evening when I get home,, It just feels like it is not opening up and running, takes longer to get up to speed and speed is down even on the flats, on hills it feels like I am pulling a heavy load. The engine seems to run just fine setting in neutral. Revs up smooth and as far as it seems to need to go. I thought about taking off the muffler to be sure there was no restriction, but it sounds the same as before and runs fine in neutral so I have not.

I still have the 3tn66 setting in the garage and as far as I know the fuel system was working fine when the last owner cracked the head and fried all 3 pistons by running it with no coolant. So I have spare parts

My Father was a great diesel mechanic, unfortunately I always depended on his expertise.
 
PPosey

PPosey

Twelve Pointer
At the advice of our local bus garage I did add some diesel Kleen to the tank last weekend after checking the intake and replacing the fuel filter, which looked fine. I have not had much of a chance to run it though since then. They thought that fuel system components could be partially stopped up?
 

JohnDeereMan

Six Pointer
You need to check fuel pressure to the injection pump. If it sits and idles fine and loses power when under load more than likely not getting sufficient fuel pressure. I have never had a gator with clutch problems really feel weak like you are describing. Mainly see shifting issues with clutches. Check fuel pickup in tank and I have also seen old fuel lines collapse from internal deteriation. I would first check fuel pressure to injection pump, second fuel lines, third fuel pickup. Diesel tanks bad for growing algae. We really do t see much happen to diesel gators they seem to run forever.
 
JoeR

JoeR

Eight Pointer
JohnDeereMan said:
You need to check fuel pressure to the injection pump. If it sits and idles fine and loses power when under load more than likely not getting sufficient fuel pressure. I have never had a gator with clutch problems really feel weak like you are describing. Mainly see shifting issues with clutches. Check fuel pickup in tank and I have also seen old fuel lines collapse from internal deteriation. I would first check fuel pressure to injection pump, second fuel lines, third fuel pickup. Diesel tanks bad for growing algae. We really do t see much happen to diesel gators they seem to run forever.
Click to expand...

Ever see a return line get restricted on one and cause low power? You talking about collapsed lines made me think of it.

Joe
 
PPosey

PPosey

Twelve Pointer
alright the bed will come off this evening and I will give every line a close exam, Thank for all the advice,, now I need to come up with a pressure gage, bet I can rent one from the local shop if I cant find one in Dads shop.
 
PPosey

PPosey

Twelve Pointer
JohnDeereMan said:
You need to check fuel pressure to the injection pump. If it sits and idles fine and loses power when under load more than likely not getting sufficient fuel pressure. I have never had a gator with clutch problems really feel weak like you are describing. Mainly see shifting issues with clutches. Check fuel pickup in tank and I have also seen old fuel lines collapse from internal deteriation. I would first check fuel pressure to injection pump, second fuel lines, third fuel pickup. Diesel tanks bad for growing algae. We really do t see much happen to diesel gators they seem to run forever.
Click to expand...

what kind of pressure should I be seeing??? I will find a pressure gauge one way or another if I cant find something obvious when I pull the bed and really go over everything
 
PPosey

PPosey

Twelve Pointer
Great green gumdrops what a pile of fuel lines this thing has,,, from the tank to a small exterior manual pump on the side of the motor,, back to the fuel filter near the tank, from the filter back to a fitting on the "main injector pump?" also a line from this fitting runs back to the tank, and another runs to each separate injector, not to mention the 3 metal lines that run one each to each injector. Kinda flabergasted on where to start.
 

JohnDeereMan

Six Pointer
All you need to check is rubber from tank to transfer pump, filter to injection pump. Check rubber line coming from injection pump that's a return. See if they feel real soft. I can't remember pressure at pump we just sight test them mostly.
 
PPosey

PPosey

Twelve Pointer
Gave each fuel line a good visual check, found nothing, there are places where the line has a bend but nothing that feels like it would restrict flow, the return line that runs from the injectors back to the fitting where the main fuel line runs into the fuel injector pump is loose,, it is a clear plastic line and a much smaller diameter than the main lines. I will get more of it Monday and replace.. May go ahead and replace all the fuel lines just to rule that out.

This is the lift pump my engine has.
http://www.ebay.com/itm/152268481163?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
 
PPosey

PPosey

Twelve Pointer
Now this is something that I thought of last night,,,,

Back when I still had the drive clutch causing problems I also had the issue of a lack of power, at that time I could shut down the motor and recrank it and the issue would go away, sometimes I had to cut it off twice to have the lack of power go away.

This led me to believe that the fuel cutoff solenoid was sticking sometimes partially retracted. I pulled and tested the solenoid and it seemed fine, then I replaced it with the one from the original gator motor that seemed to have a little more snap to it's retraction,,, this made no difference.

WHAT IF the problem is not the solenoid but with the linkage that the solenoid controls,,, could this linkage be sticking and not fully allowing open fuel flow even when the solenoid is retracted.

I think I will pull the solenoid, carefully mess with the linkage some to determine if it seems free to move, cover the solenoid hole with a cover plate, I have the plate from another engine, and see how it runs from there, I should be able to choke the motor down to kill it with the solenoid removed by covering the air intake should I not?

Can you guys with more experience see this causing issues????? Can the fuel shutoff linkage be damaged by running the motor with the solenoid removed?
 
Last edited:
PPosey

PPosey

Twelve Pointer
well all new fuel lines did nothing,,, 17 feet worth,,, Wednesday I will tackle the fuel rack
 
JoeR

JoeR

Eight Pointer
PPosey said:
WHAT IF the problem is not the solenoid but with the linkage that the solenoid controls,,, could this linkage be sticking and not fully allowing open fuel flow even when the solenoid is retracted.

Can you guys with more experience see this causing issues????? Can the fuel shutoff linkage be damaged by running the motor with the solenoid removed?
Click to expand...

Possible? Sure. Likely? Doubt it. I've never seen anything like that happen, but I've never fooled with that style pump either. All kids of odd things happen to vehicles that are particular to that style vehicle. Name a car, truck, tractor, motorcycle...whatever, and someone that works on them all the time can name what the common failures are on them.

Shutting it off and having it recover does point to a fuel problem. Maybe something as simple as plugging the fuel pickup. Maybe something more sinister, like injector pump wear. Your next move it to get a gauge on it and drive it. If you get tired enough to drag it to Greensboro, let me know. Bring it to the house and we'll figure it out.

Joe
 
PPosey

PPosey

Twelve Pointer
That would be a longg drag but thanks for the offer. I have 2 extra injector Pumps on motors, both used low hours. I found several examples of this type of sticking with the fuel flow stuck in the on/partially on position and a couple stuck in the off, mostly similar yanmar motors used on boats, will be a easy check due to a access plate.
 
nccatfisher

nccatfisher

Old Mossy Horns
Contributor
How is the injector pump timed? Could the timing possibly gotten a few degrees off? That will make them sluggish.
 
PPosey

PPosey

Twelve Pointer
Seems it is timed with shims/washers between the pump and block, says to go back with the same sized shims if removing the pump for service, pretty much no way it could move there.
 
nccatfisher

nccatfisher

Old Mossy Horns
Contributor
PPosey said:
Seems it is timed with shims/washers between the pump and block, says to go back with the same sized shims if removing the pump for service, pretty much no way it could move there.
Click to expand...
OK, that eliminates that. Most that I am familiar with you can twist the pump a few degrees like a distributer. Not as many of course but around 6-8* each way.
 
You must log in or register to reply here.
Top