John Deere 990

Was using my 990 today and doing some finish mower on side of bank. Obtained air in injectors as tank was about 3/8 full. Has anyone else had problems with these 990. I removed filter body, changed filter added fuel and delivery was good but I note that they placed the filter body almost even with the tank. The tank being behind the seat. I may add another bracket and lower that filter body. There is a pump but the filter body has trouble siphenoning at this level. There's no way to raise the tank as it has shrouds. I wonder way John Deere made this Pi** poor design. comments appreciated.
 
Texas Jim, do you have a good model to consider...I've thought of it...but didn't know pressure requirements....it looks like John Deere changed the delivery system 3 times so they were aware of the problem...looks like they could have made a simple above engine fuel tank even gravity flow with no problems...looks like intelligent iqnorance at work.
 

I think pressure for most fuel pumps is a non issue. I added an electric fuel transfer pump to my previously owned Kubota M4900 with no attention paid to pressure and it operated fine. My orange tractor with a loader was a PITA to pump hand pump hidden towards rear of engine with loader frame in the way.
 
The product liability courts have pretty well decided that fuel tank above engine is a bad design.
 
Why not just simply bend the float arm to show its out of fuel before it does run out or check your watch for hours to run before the tank goes empty. The fuel sender part # AM877195 ,key 23 .
 
(quoted from post at 11:44:50 07/22/16) The product liability courts have pretty well decided that fuel tank above engine is a bad design.

It appears to me that newer style tractors with lower mounted fuel tanks burn fairly well after they catch on fire. I've seen a lot of older tractors with gasoline tanks mounted above engines that had no problems with liability
 
Lot's of advise but none conclusive. I conclude a bad design. Mounting tank aligned with tractor would have been the right design but per my research JD decided to build the 990 on the cheap so this is what I have. May add an auxiliary tank under the hood. Tks for replies Chuck
 
Probably due to the fact that most fuel tanks these days are molded plastic so they can conform to
the chassis and hold the maximum capacity while older tractors of course have steel tanks. Makes
quite a difference in how aggressively a machine goes up in flames.
 
Where is your tank outlet? Reason I ask is a decade or so ago when I was at Deere we had to update a few tanks mounted behind the seat for the same issue. Deere's quick fix was to add an outlet to the other side and install a T fitting and a line between the two outlets as the original only had one. That way on a hillside it would still pick up the fuel no matter which way was it was leaning. They were supposed to make new tanks to be installed later but all I saw were the kits.
 
M-Man no doubt the outlet was on the uphill side while mowing. It got some air and then problem develops. Now having said that I wonder if I could add a t to the inside and a hose horizontaily much like weed eaters and the like do...I might get on of the outlets and see if I can put a copper tube to the other side....I think I might rig around the problem but it's a shame to have to do so...engineers must have had a brain f*** when they designed this.
 
M-Man: I can get the nozzle and gasket and not opposed to removing the tank and adding another outlet. I wonder exactly how this was accomplished. Was there a threaded outlet used or a nut welded on the tank...I suppose with diesel fuel I could braze this on without an explosion. I think the metal is too thin to hold without a flared nut or a thick threaded washer. would appreciate your advise. Best Chuck
 
Sorry but it's been too long and my memory ain't what it used to be. I don't remember welding or brazing on the tank but I woulden't swear to it. Probably the only reason I remember it at all is they were pert near brand new tractors and here I was drilling a hole in the fuel tank and patching it up. It worked fine just didn't sit well with me having to do it. I don't think a real Deere engineer ever looked at that tank design and if one did he never saw the hills here.
 

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