Kohler K321 S Fuel Pump Woes?

[BigSix]

Hi all: Appologies to the faithful, as I do have two or three large frame Simplicities personally, but I have a question about one of the "other tractors." I've seen Wheel Horses discussed with some respect here, so I hope you all will indulge me. I mean, a Kohler's a Kohler, right? My buddy's 1970-ish Wheel Horse GT-14 is on extended-sleepover at my place. (His wife's not known for her tolerance,}:) and he's already harboring a large Cub and a diesel John Deere--plus, I'm not done fixing it yet, so I get to "use" it to mow my lawn--which I was able to do exactly once, last year--lol. Let's see: 30+ hours of repairs, so far, plus a half-day's driving to fetch it, to get one mow job. Hmmm....B)) Anway, this very cool, heavily-built tractor, has done another "Titanic maneuver," and gone down--again. So, at the conclusion of my one mow job, (it broke with only one patch left--in the front yard, of course--lol) it began to break up and the throttle began to "hunt". When this happenend, a weird feedback loop set up between the governor and the hydrodrive, when the throttle began to hunt, so that it was actually accelerating and surging, as if I were jerking the hydro control around. Previously, this hydro's speed was steady as a rock. (This is my first ride on a hydro--and I liked it! :D) I had already rebuilt the carburetor carefully and completely, and it spec'd. out fine against the Vibra-tach. It ran fine after the carb job, as I proceeded to find the other weak links in the hitch system, belts, stripped arbor keyway, PTO clutch and the ongoing mess otherwise known as the electical system. When it started running terribly, it first died, like it was out of gas. I refilled, but no joy. Then I noticed air bubbles in the clear fuel line leading from the fuel pump to the carburetor. At least, it looked like a fuel pump. I've since read in the Kohler shop manual (downloaded version) that there IS, in fact, a fuel pump, either a metal bodied one or a plastic bodied job. (As the tractor is still buried under it's winter tarp/blanket, I didn't dig it out to confrim, but given its age, I'm betting it's the metal pump.) The engine is a 14 h.p. model K321 S, Ser. No. D259205, Spec. No. 6010B. My Four Questions: 1) Given that it would only idle consistently, but would then hunt and die when the throttle was opened and even a minor load applied, like moving across the flat ground, are those bubbles normal? Or do they definitely indicate a fuel flow problem? I'm pretty convinced there's a fuel flow problem, as I feel the machine got a little hot before I realized it hadn't just run out of gas--I think I saw some hot vapors rising off the cowl (even though I'd cleaned the cooling fins under the cowl previously) and I think I saw some glowing carbon spark out of the exhaust. It did not appear to have overheated seriously, before it shut down. As I say, it did restart, and idle pretty smoothly, but seemed to lean out and die under any load. 2) The other possibility I'm considering is that there is a fuel restriction in the tank. I noticed that the clear plastic, paper-element, in-line fuel filter I installed when I rebuilt the carb, was not even filling to the halfway point, as it did when I first installed it. Rather, now the gas is falling down the inside wall of the horizontally-oriented filter, and running across the "bottom" (actually, the side) of the filter, on it's way to the input hose to the carb. 3) Is there a diagnositic procedure I can follow, to confirm if the pump's diaphram is bad? Or do I just disassemble the pump and inspect? The tank is plastic, ancient and I believe is a ***** to actually remove. 4) Any other suggestions, comments or question? The grass is growin', and She says I should be mowin'.... Thanks in advance, Peter

[Brent_Baumer]

I don't know about the tank location on a Wheelhorse but if the bottom of the tank is higher than the carb like on the Sims and AC's you can by-pass the pump and let it gravity feed w/o problems. Even if you let the tank level get low. BTW - Rokon gave me that tip a few years ago when I was having pump problems. I bypassed the pump on that engine and never thought about it again. Brent

[BigSix]

Brent: Thank you--I should have specified. The tank is actually quite a bit lower, at it's bottom, where the outflow fitting is, than the carb. The tank is in a goofy location, IMO, in that there's this massive, cast iron "radiator shell", at the front of the tractor. Looking at it head on, you see these horizontal ribs going across the front of the "radiator" (if it were a water-cooled engine, this would be the radiator). Well, what you see, inside the perimeter of this cast iron shell, is the (unprotected, from the front!) plastic gas tank itself. It's standing up, like 18" tall, by the width of the hood/grill, and (from memory) about 7" thick. And the fuel outflow is on the very bottom of the tank. The ribs you see, when looking at the front of the tractor, while basically the same red color as the cast iron shell, are just formed into the single-wall, plastic gas tank. The cast iron shell just surrounds the sides (and top) of the tank, but not it's front surface. I mean, I really like the tractor, it's power, handling, three-point hitch (!), huge rear tires, etc..., but this one aspect of it is puzzling, at best.:o) I say it's a goofy design because, from the driver's seat, you see this massive (1/2" thick? More? Haven't looked at it since November) CAST IRON radiator shell, yet if you were to drive too close to a sharp stick, you'd poke it right through the tank. I don't think there was ever any screen over this tank/grill thing either, though this tractor has been run hard and put away wet. I've seen some pics on the internet and they all looked the same. But I will remember your tip, for any tractors with a high-mounted tank, like a Simplicity, and Kohler power. That's definitely an elegant (and "simple") solution, and at the right price, too! Thanks Brent and Rokon! Peter

[firefoxz1]

Yes I would investigate the fuel pump. An engine will run hot when running way lean(out of gas). All the symptoms does point to the fuel pump at the moment. Disconnect the line at the carb and crank it over making sure the fuel line outlet is higher than the tank and see what the fuel flow looks like, remember it could be a retriction at the carb inlet(piece of the inside of the hose flaked off) causing this as I have had this after having a carb off unless I installed all new hose atleast from the filter to carb.

[Salthart]

The bubbles in the fuel line say a lot.. It is far easier for air to get in that for fuel to get out and if there is a lot of lift from the tank to the pump, then you may see a problem if you have a air leak in an old line. The second thing is a restriction in the fuel filter/tank screen That would do the same thing. As to how to go about dialing in on the problem, get a pair of needlenose Vice-grips and adjust them to close off the fuel line. Run the tractor till the surging starts and close the fuel line and shut down the engine. Remove the fuel bowl from the carb and see if low fuel is a problem.. Loose fuel pump mounting bolts can cause the same trouble and a bad check valve in the pump will do it also. My advise ? Replace the fuel lines and filter,clean the tank screen then run it again. ( At the age of this machine it likely needs doing anyway ) If you still have trouble, Check fuel pump pressure or simply replace it as you have taken care of most anything else in the fuel deliver system.. Oh, BTW, You may want to check the crankcase oil for gasoline.. Good luck

[HubbardRA]

Easiest way to find out if it is the pump is to somehow attach a small tank (gasoline container) at a point higher than the carb, then connect a fuel line directly to the carb from this tank. If the problem does not present itself with this setup, then it is either in the fuel pump or the associated fuel lines.

[Al]

Hi, Sounds like you have an air leak on the suction side of the fuel pump. Good prospect cracked fuel line or air leak where it connects to the tank. If the tank outlet is on top and it has a pickup tube check it for a crack. Al Eden

[BigSix]

Thank you, everyone, for your very helpful responses. Unfortunately, I have to apologize for not getting back sooner, as I received a rush assignment shortly after I posted, and I haven't even been able to dig the tractor out and get going on it. I will be able to once the weekend gets here, assuming it doesn't rain. And I can't wait to get going on it, now that you've given me a clue.;) Thanks again--I especially appreciate it since it was not the Orange and Yellow. I will let you all know what I find, and comment specifically, then.

[gretsch]

I had a problem similiar on an Ariens Gt-14. It would run fine then not. Start and run fine one day, not start at all the next. If you have a spare electric fuel pump lying around (highly recommend), hook it up and see if the problem goes away. On the air bubbles, I would follow Al's advice on resolving that. I am not sure though that that would be enough to cause the engine to die. I have a clear return line on my Powermax and it is common to see bubbles leaving the carb. By the way, those are very good engines in my opinion.