Jlg 40H issues

Have a Jlg 40h with ford 423 motor. Rebuilt carb but still doesn’t seem to idle just right. Will fire right up 9 out of 10 times but every so often it won’t crank for anything. Takes numerous starts to get an attemp to fore them runs crappy for 2-3 mins before leveling out. Carb rebuilt, new fuel pump, new fuel shutoff solenoid. I have a clear inline filter just after gas tank. Filter never fills with fuel. Not sure why. Could that mean carb isn’t getting enough fuel? also machine doesn’t want to shut down unless I kill master switch. It wants to diesel if shut off normal way. I replaced fuel shutoff but it’s still doing it. Any thoughts or advice?

Those clear plastic fuel filters very often don't seem to fill up. The engine doesn't care, they run anyway. Dieseling on a gasoline engine is a function of idle speed. Have you maybe got the idle speed set using the screw on the throttle plate rather than letting the governor do it? Does the power to the fuel shutoff stop when you turn off the ignition ?

Maybe you are right about that clear filter. It seems to run ok for most part. The idle screw could be set wrong. I had a mechanic help me rebuild and setup the carb. He is top notch mechanic but he could have it adjusted wrong. I’m gonna hook a light to the fuel shut off and make sure it does loose power. Will update soon.

Little help needed. Having same issues. Couple cylinders started leaking. Machine sat for 2 months while fixing his cylinders. Now it won’t badly run. Idle at best when loaded it shuts off. So I’ve tried to swap to LP. Those was leaking and nasty so I temporarily rigged up another hose. Machine cranks and idles great but again when loaded heavy it shuts off. it’s like it can’t get enough fuel or floods. I bypassed the relief valve when I rigged hose. I notice one fitting has a spring and maybe some type office in it. Could that be the issue? Do I possibly need to rebuild the lp regulator. I’ve got new hose made so I’ll try it soon. I was hoping to avoid the 700-800 new carb. Any ideas would help.

One thing about propane, the "window" of fuel mixture is actually very narrow. Too little propane, it won't ignite. Too much propane won't ignite either. Bypassing relief valves probably won't work for you. Google says the flammability range is from 2% to 10 percent. Not much wiggle room. Strange though that both fuel systems are acting the same way. A weak ignition will crap out as soon as the engine is under load and cylinder pressure rises to a point a weak spark will no longer jump the gap.

Off- I would say both girls act the same. On gasoline it will barely run period. ON Lp is idle great and and I can manually move the throttle and it will rev way up and hold. Will rev to the point that I back off because I think she’s turning too many rpm’s. But when I load hydraulics the motors doesn’t rev high enough and stalls. Usually shutting off.

So do you suggest new plugs and wires maybe?

sounds like maybe the governor is messed up? You make it through the hurricane ok?

Still fighting this issue unfortunately. I purchased a new carb (700$). She runs little better but still does not want to idle correctly or stay running. Seems like governor wants to push idle to low or cut fuel all together. This machine has a precision governor (I think that’s name) rectangular box with linkage to carb. Anyone here have experience trouble shooting governor??

I had some precision governor information/setup info. Looking for it

OFF said: I had some precision governor information/setup info. Looking for it Click to expand... I found some info on the precision governor website but haven’t had time to trouble shoot yet. However I’m having some type of electrical issue and may need some help figuring this electrical drawing out. Some times the machine does not what to crank. I push start button and get nothing other man I can hear fuel pump pumping. After numerous button pushes and key cycles it will usually engage the starter. Loooking at the electrical drawing it looks like power to starter solenoid if feed through precision governor. I have a test light guess it’s going to be a process of elimination. Looks like power from push button goes to #7 on terminal strip at front motor. Them that #7 goes into governor via 4-pin connector on b pin. Then come out govener on 8pin connector via g pin. Then to start lock out relay and on to starter solenoid. Make sense?? Could governor be engaging stater lockout relay?? Precision governor says it is only engaged after 500 rpms.

I would think the only reason there is a wire from the governor to the starter lockout relay is to prevent you from cranking a running engine. There are a whole series of Bosch type relays in the main ground panel, I would think your problem lies with one or more of them. I haven't found my Precision Governor information yet. I searched home, it's not here. It must be at work. But the instant I walk into work, I see a thousand squirrels, and I forgot all about looking for your info. I'll write myself a note, leave it in the truck.

OFF said: I would think the only reason there is a wire from the governor to the starter lockout relay is to prevent you from cranking a running engine. There are a whole series of Bosch type relays in the main ground panel, I would think your problem lies with one or more of them. I haven't found my Precision Governor information yet. I searched home, it's not here. It must be at work. But the instant I walk into work, I see a thousand squirrels, and I forgot all about looking for your info. I'll write myself a note, leave it in the truck. Click to expand... I used a test light today and each of the relays for ignition cut on when key is turned on. The start relay allows power thru when start button is pressed. Sometimes it still just clicks. I can’t figure out the electrical drawing 100%. I work in electrical field in a power plant, this drawing is not like anything I’ve seen before. So again, usually can cycle key and press button over and over and eventually it will crank. The 4-pin and 8-pin plugs for the e-331 precision govenor controller had some corrosion in them. I clean them with electrical clean. Not perfect but much cleaner than before. This is one hell of a troubleshooting process

OFF said: I would think the only reason there is a wire from the governor to the starter lockout relay is to prevent you from cranking a running engine. There are a whole series of Bosch type relays in the main ground panel, I would think your problem lies with one or more of them. I haven't found my Precision Governor information yet. I searched home, it's not here. It must be at work. But the instant I walk into work, I see a thousand squirrels, and I forgot all about looking for your info. I'll write myself a note, leave it in the truck. Click to expand... Off: I need little troubleshooting help. Still having the no crank issue occasionally but have bigger issues at moment. Machine was running really crappy on gas so I’ve swapped to Lp just to see how it went. It starts right up and idles well on LP. It does ok but will shut off when hydraulics become loaded. Once it shuts off it does not want to restart for a a few. Machine is back firing bad on both fuels when it shuts down from overload. Each start it flows fire out exhaust. I’ve changed plugs and wires and coil. Should I possibly look into replacing the ford ignition module? The ones I find online are expensive. Would ignition issue be the most likely cause of backfire? Possibly crank position sensor?

Is this the 2.3 engine with a distributor? It sounds like a problem with the pickup coil in the base of the distributor. They typically fail when hot, work when cold. Is the ignition module remote mounted on the frame, not on the engine?

Yes 2.3 distributor less. I have replaced the coil with one for a 2.3 ford ranger. Looks same. The ignition module is mounted on what I’d say is frame above the hydraulic pump. I’m wondering is ignition module could be an issue? Runs on gas but skips a lot but will run good for short moments. New carb 2 years ago. Non-ethanol gas only. Back fires on re-crank if it stops running. Runs well on LP but does not take a load well. Have to really feather controller when moving machine to prevent it chocking off. If it chokes off it back fires bad on re-starts. Could crank position sensor cause any of this?

I've worked on a few of these and the Ford Ranger coil will work just fine, I have also found that the only spark plug that works well is the Autolite Iridium plug. Those Zenith 1 barrel carbs are a problem and trying to find a "good" new one can be a bit challenging. JLG did an update on the ignition module a few years back, probably 15 or 20 now that I think of it, it's a spendy kit but well worth doing, it makes it run much better. I will see if I can find the info on it with a part number.

OFF said: I had some precision governor information/setup info. Looking for it Click to expand... Do you remember which model that is? I should have info on it if you can't find yours.

excavator said: Do you remember which model that is? I should have info on it if you can't find yours. Click to expand... I think it’s E-331

I’ve been trying to use the machine all weekend and it’s been frustrating. It will idle well on LP but does not do great under loads. Shuts down or chokes off. Backfire almost everytime I try to restart, blows exhaust cap off. Could the back firing be due to timing? I’ve found a new ignition module but it’s $1300. I don’t mind replacing it if it’s faulty but hate to spend that much and still have same issues. Any thoughts of ways to test?