New to JD with an LX178

[jeepcoma]

Hi all, first let me say this site has been great, I've learned a lot already searching through the archives and decided to sign up.

I just picked up a non-functional LX178. Owner wanted it gone because it's shooting gas onto the exhaust. It started and ran for the quick drive up on the back of the trailer, no idea how many hours are on it (it's a '92 model), but for that pesky stream of gasoline onto hot parts. I'm not sure if I will keep it at this point, I have a pretty small lawn and have no problem mowing it with a push-mower, but I wanted something to speed up bagging in the fall after discovering how great it was by borrowing a leaf bagging tractor last season. I'd like to get it working as cheaply as possible, to try mowing with it once or twice and give it a chance to win my heart, then decide to either sell it or actually spend money on it to get it tip-top.

After removing the cover and poking around, it was clear there were mice living under the hood and I was hoping it was just a chewed fuel line. My luck doesn't run so good so it was fuel spraying from the weep hole on the fuel pump. After searching the internet, it turns out this is a pretty common problem with the original pumps for these vertical Kawi engines. And holy sticker shock batman, dealer wants $150 for a new upgraded fuel pump (AM132715)!! Best I've found so far is ~$120 which is crazy , I found a reference on another site to JD discounting the pumps down to $32.75, but if it was true back then it's certainly not the case now. Seems like a major safety issue to me so I'll shell out the money if I have to, but does anyone know of a better source, or have a spare lying around for sale?

Alternatively, can these be fixed? I removed the unit and was playing with it on the bench (ok, in the kitchen sink) trying to see how it worked. It seemed like if I used "normal" hand pressure to operate the pump, it worked just fine, but if I really gave it a good blast that's when fluid would come out the weep hole. Sounds like a torn diaphragm but I would probably have to destroy the pump to take it apart, it looks like the cover is sealed on by the lip pressed around the outside. Anyone take these apart before? Anyway, even if I did fix it, I would be stuck with a fuel pump that will again spray fuel onto the exhaust when it fails; the new upgraded design with a fitting to hook a line onto seems a worthwhile upgrade. Mostly though I'd just like to see how this tractor works out before decided to put a bunch of money into it.

The muffler has basically rotted and split in half, the big canister is just hanging by a few pieces of rust and ready to fall off after one good bump (actually surprised it survived the trip on the trailer). Sticker shock continues (beginning to see why they paint them green) with a list price of $255! Oh well, I'm used to mowing with earplugs anyway. A used replacement part seems a good alternative, if I can find one.

Cosmetically, everything has mostly faded away, so I don't have a clue what buttons and knobs do what. I figured out how to start it and the parking break, but when I pulled a knob that might be the PTO engagement, the engine just stalled out. I'll need to check if the blades are frozen, seat safety switch is bad, and other things? There were some wires cut under the hood, but I think it's just for the headlights (since I found those under the seat). I bought the original manual and service manual CD so I'll start figuring this stuff out once they arrive.

I did replace the fuel lines, coolant lines, spark plugs so far, and wow it starts right up now and purrs like a kitten. I'm kind of disappointed I don't need to rebuild the carb, and I didn't even have to tinker with it. Maybe there is something to the JD name after all...

 

[rayikeo2]

Fuel pumps are not servicable. It is a safty/fire hazard if leaking. It will have to be replaced if you have not done yet, do not run mower until fixed. If you can buy one for 32.50 you better jump on that deal if it is the correct one. The bad pump could be the reason the motor dies when engaging the blades or it could be the wiring the mice chewed on. Broken wires can keep the mowing deck from engaging.

 

[jeepcoma]

I got my new fuel pump (the upgraded model) and replacement muffler in yesterday. Before buttoning everything up, I attached the fuel line to the pump and pumped by hand to see if it worked. After a few pumps gas came shooting out. Great! Put everything back together, motor started up just fine, and everything seemed to be working.

After a few minutes of idiling, I though i would lower the throttle down from about halfway to see how low I could get it. It started to sputter so I raised the throttle back but it died out, and would not restart. If I let it sit for a minute, it would fire like normal but only run for a second or two (or longer if let it sit more, seemed to be about one second of run time per minute of resting). My first guess would have been the fuel pump, and that my playing with the throttle was just coincidence as that was when the carb bowls ran dry, except I did check the pump first. I unscrewed the gas cap and didn't hear any vacuum, so that's odd. Plugs are brand new so there's no chance they are fouled.

I still suspect gas, but it also sounds like a safety sensor is cutting in since it dies out like you kill the ignition; there's no sputtering or wheezing or odd sounds, it's just runnign one second and then it winds down. I tried starting with the PTO on, and no crank, PTO off and it cranks so that's working. Same with the seat switch, and if I leave the enging on "on" I can hear the relay click when I raise or lower the seat. It was dark so I gave up, but tonight I'll pull the fuel line and make sure it's pumping, check that there's gas in the bowls, pull plugs to look, check that plugs fire, and dig in to the service manual. Could be a plugged vent on the carb or something (and original reason for pump failure?) else that's blocking flow (I did also check that the fuel cutoff was in the "flow" position!)? I gave it a brief go this morning and got nothing.

 

[rayikeo2]

Do you have a solenoid on the carb that has an electric wire clipped on the front of it? If so, that is an electric fuel shut off that works with the ignition switch. Key Switch on gets voltage to the solenoid. Switch off = no voltage. (You can hear a click if working) Check to see if 12 volts is getting to the solenoid as you turn the switch on and off. (Note for this to work parking brake must be engaged or someone sitting in the seat with the clutch in. Also see if after it starts it will keep running only if you give it about 1/2 choke. It seems funny but bad electric connections can cause your problem. You may have to look for briken or chewed wires.
With the correct vented gas cap there will not ever be a vacuum release when you take the cap off. The vent prevents vacuums. If the gas cap was bad it would take about 30 min running before a vacuum would occur, not 2 or 3 min.

 

[jeepcoma]

I checked the fuel pump first just because it was so easy to get to. Turns out it's broken Seems like the internal piston or whatever it is that actually pumps the diaphram is hung up, it won't return down so the pushrod actuated cam just flops around. The service manual doesn't say anything special about installing it (like having to lubricate beforehand), and it only goes one way, so I'm pretty sure I didn't botch the install. Still though, first I've heard of a fuel pump failing like this. Maybe there's something dumb I'm missing?

 

[jeepcoma]

I decided to come to my senses and ditch the stock mechanical fuel pump. Instead I went over to the auto parts store and picked up a Mr. Gasket 12S electric pump for 1/3 the price of the stock pump at dealer prices. For now I just have it temporarily hooked in, but everything seems to be working great so I will create a more permanent mount and wiring for it.

Currently I have it ziptied to the frame above the front left wheel, which keeps it out of the hot engine bay and allows for the proper mounting angle (45*) and also is lower than the gas tank. I'm not too keen about the location since I'm slightly worried about damage and exposure to the elements, but it's a bit too large to put anywhere else, and at least I can keep an eye on it and inspect/replace easily if anything goes wrong (and also keeps fuel leaks away from hot engine and exhaust). I might try to relocate it back towards the seat more, in the cavity where the fuel cut-off switch lives, if I can get it to fit and also mount at the proper angle.

Since the previous owner cut off the headlight wiring, I hooked it into that so that it's both switchable on and off and also always off when the ignition is killed. I'm worried about burning up the corroded wiring (supposedly takes up to 3 amps peak current) so I'll have to look through the service manual and find a better wiring location, or perhaps just hook up a relay of something, but anyway it was good enough for me to find that everything seems to be working great now!

Starts right up every time, idles nice and smooth, PTO engages nicely, even cuts the grass. Next step though is to remove the cutting deck and check out the blades, and probably just replace them with something better for mulching. I've heard mixed things about the "gator" blades, some say good, some say bad. I'm also considering a few of the mulching kits, I find the JD ramp/blockoff plate kits for about $100 online. I really want something that's great for mulching grass in the summer, but also works for bagging leaves in the fall as well (which means I need to find the bagging equipment too), so I've got some research to do.

And while I'm at it, coincidentally I am looking for a new snow blower before winter starts, and found there are snow blower attachments for this! It this enough tractor for a 38" blower/throw attachment? How far can it throw a foot of heavy wet snow? Is it even worth spending say $250 for a snow attachment or am I better off spending it on a dedicated snow blower instead? (I like the idea of multifunctionality and also not having to make small engines sit unused for months at a time) Which models can attach to it? I'm finding some for the STX38 and it looks like they are compatible, but there were two models of that thrower (89-90 M02460X or M02461X, 91+ "The M02462X is a 38" blower for the LX100 Series"); sounds like the second one should fit.

 

[yellowrosefarm]

I know this is an old thread but I ran into a similar situation today and thought I would bring it back to the top. An old fellow I know called me over to help him put a new fuel pump on his LX178. At least 3 other people had tried to get this thing going and at least 2 pumps had been purchased. (ouch) When I looked at it, the pump diaphragm was stuck as described above so that the actuating arm was just floppy on it's pin. What caused it was that someone in the previous line of "mechanics" lost the insulator that goes between the pump and the block. Without it there taking up about 1/4" of space, the pump actuating rod coming out of the block was too long. When the pump was tightened down and the engine cranked, either the cam or the pump arm had to go. So the loss of a $3.83 insulator caused having to buy 2 $140 pumps.

 

[Tenn_Blue]

Since you brought it back up.....
I had the fuel pump on my lx178 go out as well. Trip to local auto parts place yielded a generic electric inline fuel pump. Wired it into the ignition switch so it comes on with the key automatically. I zip tied it to the frame beside the engine in a safe spot.
Not sure I needed it but I made a plate for the hole where the original fuel pump went - keep out dirt and such....

Mower runs so much better - doesn't seem to hunt as much. Net cost - $45.00

And these are good mowers! We got ours used and it has run faithfully for several years - aside from the fuel pump and an idler belt needing replacing, its been dependable as a rock!

 

[jeepcoma]

I had the fuel pump on my lx178 go out as well. Trip to local auto parts place yielded a generic electric inline fuel pump.

I seem to have developed a (not entirely unexpected) problem with my electric fuel pump. I went to start up this weekend, and was greeted with a very smokey and barely running engine. Usually I have a single puff of smoke after it's been sitting but nothing like this, my tire was wet with fuel being blasted out the muffler after just a few short moments (I was letting it putt along to see if it would clear up).

I turned my fuel pump off (I have it wired to the headlight switch) and after a few seconds it ran normally then puttered out as it ran out of gas. Turned the pump back on, same conditions as before. I figured out that if I left the pump off, and briefly flicked the fuel pump on and off every few seconds, it would run like normal indefinitely. So I took the carb bowl off, it looked pretty clean in there. If I held the float all the way up though, and turned the fuel pump on, gas would still come out. So I'm hoping a piece of grit or something is just blocking the needle from seating all the way.

Anyway, the electric pump was the smallest, lowest pressure I could find, but I think it's probably still way overkill compared to the fueling requirements. It can't be good for the carb to have to deal with 100x the flow volume, even when in good condition. I think I should fix the fuel delivery as part of the problem.

Questions:

Should I install some kind of flow restrictor until my flow rates match what the stock requirements are, to prevent future problem? Or some kind of diverter valve that redirects a portion of the flow back to the gas tank (I think this is preferable, does not raise line pressure and lets the pump operate without restriction).

Are there any carb "upgrades" that I could install from another unit that deliver better fueling efficiency, or just for a new replacement? I've been looking for rebuild kits but haven't had much luck so far. If I had the free time right now I think a home-built megasquirt EFI project would be fun, but for now I just need to get it running to start mowing all these leaves. I REALLY don't want to have to be driving one-handed and flipping the fuel switch on and off the whole time!

 

[jeepcoma]

I seem to have developed a (not entirely unexpected) problem with my electric fuel pump.

<snip>

Should I install some kind of flow restrictor until my flow rates match what the stock requirements are, to prevent future problem? Or some kind of diverter valve that redirects a portion of the flow back to the gas tank (I think this is preferable, does not raise line pressure and lets the pump operate without restriction).

In case anyone reads this in the future, I eventually figured out my real problem was a stuck choke! It had gotten gummed up enough that by moving the throttle from the "start w/choke" position down to the "fast idle, no choke" did not actually disengage the choke. I'm having more spark issues but thought I would give an update on the fueling issue. I may still consider adding some kind of flow restriction, but otherwise once I readjusted the throttle operation it was working just fine.

I also added the JD mulch kit (special blades and blockoff plate) to do my leaves last year and it worked amazingly well. I did nice tight, overlapping circles, like driving a zamboni, and the leaves just disappeared. By the time I got to it all the leaves were down (and I have a TON of trees) and it turned what's usually a solid three weekends of bagging by hand into just a few hours of mowing in circles. Highly recommended for the ~$100 or so you can find them for sale. Works on the grass too since it's adjustable.