Jlg 40H issues

Excavator or off, I think one of you posted a while back tht you had found a replacement for some of the relays. I’d like to try and replace the relays for start circuit and over speed relay.

excavator said: 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. Click to expand... From what I can find the jlg update to ignition module is obsolete as well. I see some folks repairing and making new modules. $1300 One new module does not use the vacuum hose. Wondering how that would affect ignition control. Thoughts?

rbcanaday said: From what I can find the jlg update to ignition module is obsolete as well. I see some folks repairing and making new modules. $1300 One new module does not use the vacuum hose. Wondering how that would affect ignition control. Thoughts? Click to expand... It's been a while since I did one and don't remember everything but I'm sure I saved the paperwork that came with the update kit. I saved it, somewhere? I'll look for it when I have a bit of time.

excavator said: It's been a while since I did one and don't remember everything but I'm sure I saved the paperwork that came with the update kit. I saved it, somewhere? I'll look for it when I have a bit of time. Click to expand... Well I had machine running somewhat decent but today it all went down hill. After a few hours use I shut it down and it would not start back. After some trouble shooting it appears machine has no spark. Ignition module is getting 12v, spark plug coil is getting 12v. Coil reads 1ohm which is good per service manual. Appears the ignition module may have officially kicked the bucket.

Got new aftermarket ignition module installed. Runs a little better but still have issues that I cannot pin point. On gas it runs really bad, skips and I assume it’s carb related as it runs much smoother on lp. However it’s been tough getting machine to run good under a load on lp. Idles great, but once platform pedal is depressed and machine tries to idle up it all goes down hill. Seems like throttle goes up and engine stalls. Not sure if governor response is too slow or if fuel is flooding engine. I’ve tried adjust the actuator controller some. Maybe some slight improvement but nothing great. Also if I flip switch to high speed the engine chokes off almost immediately when platform pedal is depressed. Not sure what to do next, I am going to rebuild carb soon and maybe try on gas again.

Just my opinion, but screw the gasoline. Now days we have ethanol gas, and unless you use that machine daily, even if you purchased a brand new Zenith carb, which are crazy expensive, you're going to kill that carb with ethanol gas. Instead, I'd fix the propane. A 40H is an aged machine, and if that propane regulator and lock off valve (if it has one) look like the original parts, which is likely, they're done. Replace the regulator and lock off valve. I've tried rebuilding them, both Bean and Century, never had good results, works better to just replace them with new units, they're not terribly expensive. Get that think running good on propane and put ethanol gas in the rear view mirror.

willie59 said: Just my opinion, but screw the gasoline. Now days we have ethanol gas, and unless you use that machine daily, even if you purchased a brand new Zenith carb, which are crazy expensive, you're going to kill that carb with ethanol gas. Instead, I'd fix the propane. A 40H is an aged machine, and if that propane regulator and lock off valve (if it has one) look like the original parts, which is likely, they're done. Replace the regulator and lock off valve. I've tried rebuilding them, both Bean and Century, never had good results, works better to just replace them with new units, they're not terribly expensive. Get that think running good on propane and put ethanol gas in the rear view mirror. Click to expand... You are on to something. The carb is only 3 years old. Ran good for maybe 20 hours. Sat 2 months and has never ran right again. I prefer to stay with LP. I’ll find a new regulator and valve. Maybe the regulator is sending too much fuel to the machine.

rbcanaday said: You are on to something. The carb is only 3 years old. Ran good for maybe 20 hours. Sat 2 months and has never ran right again. I prefer to stay with LP. I’ll find a new regulator and valve. Maybe the regulator is sending too much fuel to the machine. Click to expand... That's the thing. Whether it's a weed eater or a Ford industrial engine, ethanol gas will destroy a carburetor that's not used daily, like as in winter storage. If this is a "just occasional use" machine, I'd be getting the propane system in order.

And the thing about propane, more so than gasoline through a carb, propane is waaaaayyy more picky about mixture. With gasoline, it can run rich or lean through the carb, but it will still run. With propane, it has to be like perfect, rich or lean will make them not run at all. That's why I suggest replacing the regulator and lock off valve, those components have to work within tight mixture tollerances, way more than gasoline carbs.

willie59 said: And the thing about propane, more so than gasoline through a carb, propane is waaaaayyy more picky about mixture. With gasoline, it can run rich or lean through the carb, but it will still run. With propane, it has to be like perfect, rich or lean will make them not run at all. That's why I suggest replacing the regulator and lock off valve, those components have to work within tight mixture tollerances, way more than gasoline carbs. Click to expand... What about the vacuum switch? Isn’t that part for the Lp system? It doesn’t seem expensive, would you recommend replacing it ?

rbcanaday said: What about the vacuum switch? Isn’t that part for the Lp system? It doesn’t seem expensive, would you recommend replacing it ? Click to expand... If it runs on gasoline, then you switch it to propane and it runs, then the vacuum switch is working, no need to replace, but do check those vacuum hoses for age and cracking, replace as needed.

willie59 said: If it runs on gasoline, then you switch it to propane and it runs, then the vacuum switch is working, no need to replace, but do check those vacuum hoses for age and cracking, replace as needed. Click to expand... Willie, it appears the beam 120A lpg regulator is obsolete. Have you seen any other regulator used??

I wouldn't have a clue about that. And it's not unusual for older parts like that to become obsolete. That means it's time to do some internet research on what will replace the 120A, that's what I'd do.

Still fighting same issue. Machine will crank on gas but runs rough and **** off. Will idle on lpg but shuts off randomly. Machine will backfire out exhaust with both fuels when trying to restart. Could the timing be off? May valve in head? Or just too rich in fuel?? The machine does not idle up like it’s supposed to on lpg. Tries to idle up on gas but that typically chokes out engine. I’m not sure where to turn next without spending a ton. I can rebuild carb but wondering how long tht will last. I’d like to run off LPG but for some reason it does not perform well above an idle. Should I consider a new carb made specifically for lpg? I’m open to any ideas or suggestions.