Propane Blues, I think

Hey guys, I need a little coaching on propane fuel systems. I have a 60's vintage Clark lift with a six cyclinder continental. Generally speaking this old girl has been reliable and handy as hell from time to time. I thought the gradual loss of go power was electrical as the engine seemed to break down as you advance the throttle. The truck will run at an idle and you can touch the throttle a little until it begins to break down. This lift was bought used and had a former mechanical life that ended up with a low profile distributor cap let under the seat sheetmetal with a torch. Not sure this is pertinent. Anyway, out here in the country I thought the lack of power or breaking down felt electrical. I hunted a new standard vertical connection Delco cap and rotor, wires, plugs, points and condensor, and swapped the coil. No success. Pulled the air cleaner off just on the chance, no help. Checked timing by farmer method, rotated distributor to see if advance might be culpret, no help. I pulled the regulator cover off the vaporizor cleaned it, no help. Carb is next, if that's what you call it. I'll pull it tomorrow and see if there is anything cleaning might help. I'm up a stump. I got this intuition that it's not enough fuel making the engine falter, maybe regulator?, but I have no experience with propane and no service information. I can say the lift always ran poorly in the cold. Now it runs poorly in the warm. It could be cam, but it's a gradual delevopment, and it will run at full throttle without falling on it's face when the engine is cold in warmer weather. If there is an old Clark Lift guy laughing at this, please chime in. I'd like to cure this problem. I don't have anyway to trouble shoot this. Any help appreciated.

Rich, Has this problem stated or gotten worse with the oncomming cold weather? I have a MM
M670 with no choke, don't try to start it in cold weather cause it won't.

First check the line from the tank to the regulator and see if there is a filter in the line somewhere--2 in around igloo lookin' thing with a nut on top--inside a felt filter-- could be plugged---any frosting any where??Name on fuel system-- Imco,-- Centuri???

Dave, thanks. I was explaining the fuel supply piping to a machinist friend earlier in the day we never thought of a filter when we discussed the parts. Neither of us have any propane experience, but I did ask and wondered what the device prior to the regulator might be. Never thought LP would need a filter, duh. My wife is smarter than both of us. Her first question was "Did you clean the fuel filter?" I told her I didn't think there was one. More words to eat, i hope. Thanks again.

Hey John, thanks for the come back. Starting is not my problem. Even in the cold she'll light. Just won't make any power. Dave says there is a fuel filter. I don't have heat or electric in my shop yet, but I'll clean the filter first thing. I have 2 445 MM's Industrial with hoe's and a tree spade.

That Engine has a long rod that drives the distributor. It is Slotted at both ends and will pull out if you remove the distributor.

The distributor and the drive can get very worn and cause the timing to jump around scattering the secondary ignition. Pull the distibuter and pull the shaft out (the cavity is large but usually fills with crud so have a shop vac handy to suck the dirt out). If it is really worn you will be able to move and rotate the rotor a lot when not running.

Clark dealers offer a Electronic Ignition dist. if you have to replace the dist as well.
There are two different drive Rod lengths depending on the year of the engine.

I repaired The Shops 1967 Clark 4000 Fork lift at the tractor dealer with that same symptom you have described. Seem to Remember timing it around 8 Degrees BTDC. After the dist repairs.

Good luck
Sounds like some other good suggestions here too!

Haywood

Rich

Usually the fuel filter can be found inside the brass block that the flexible fuel line from the tank is connected to.

If you think it may be a fuel related problem try starting the engine with the propane turned off using a good carburetor spray.

I assume the engine is a flat head, does the distributor protrude through head, if so the distributor most likely doesn't share engine oil for lubrication, so check to see if there's a grease Zerk on the side and give it a shot of grease.

I've had symptoms similar to what your describing and it turned out to be a binding distributor, if this should be the case you may find that the drive tang & slot is worn, this can be repaired by building up the surfaces and grinding to fit.

Let me know!

Scott

Aw Crap Haywood, you beat me to it!... :wink:

Haywood & Scott, thanks guys, ( I guess?) I am out the door this AM to check the filter block in hope that the filter is the culpret. I did check the engine with starting fluid to see if it would run when I had the air cleaner off. It seemed to run ok but I'm scared of ether. We call it "Rings-be-gone". I'll try some carb cleaner if the filter doesn't help. I'll check the rotor play before I fire up. I dread gettting into dist shaft or dist because of the budget, but who knows, even a blind squirrel gets a nut once in a while. thanks again for all the input. I'll give a shout on my repair progress tonight when I get back. Going to go try to clean a pond with a rubber tire hoe for neighbor, after I check filter. Should be a fun day of extraction.

Won"t hurt to run a compression test to see where you are at.

Hey all, cleaned the filter, some rust. Not the cure. Man, I'm old news. I had to back up 3 pages to get to my post.I tried the carb cleaner as Dave suggested when the engine was running expecting it to run faster, fell on it's face. I guess I got a dist/timing problem not fuel. There is some rotational play in the rotor. I'll pull the dist out on Saturday and look for the shaft wear. Scott, I did not see a zerk fitting on the dist. I'll check the shaft when I have it out. Thanks All, for the advice. Rich

Hey guys, I pulled the trigger on my post to quick. I did have one other question. This system has some kind of a diaphram "pot" on the side of the carb. there is a wire running to a knife post & there appears to be a Vacuum line going to the pot from the intake side of the carb. Any chance this is some kind of electronically controlled choke? How would it function? I didn't have time to run the wire before I left this AM, but there is some type of switch that energizes the regulator that goes hot when the key is on. The wire leaves the neg coil to that switch and there are several wires staked together on the switch terminal. I don't know where they go. Maybe to the carb Diaphram? If the choke is stuck closed adding carb cleaner might flood it? not enough air? I'm grasping at straws. Any ideas what the diaphram could be other than a choke control? Throttle is straight mechanical. Might pull carb first? Thanks again. Rich

Rich

Sounds like the diaphragm could be a choke pull off, and yes, the carburetor could have an electrically controlled choke heater.

To answer your question, if the choke was stuck, you should have had a rich fuel mixture all along...Yes?

Prop the choke open using a clothes pin and spray the carb cleaner in using short pulses just above the air horn and see how the engine runs.

The distributor rotor will have some rotational play in it due to the mechanical spark advance so I guess at this point you need to figure out if it's fuel or ignition related.

Is the vaporizer frosting up?

Hey Frank, it will make some frost when you first light the engine. As the water circulates the frost disappears from the cover. What is queer is that if the engine dosen't light the vaporizor passes the propane through the hole in the metal cover. It may have been doing this forever and I didn't smell the propane. When I tried to cure my problem I realized that the vaporizor passes the propane if the engine dosen't light. The warmer the engine gets the less throttle you can apply until it begins to stall. I am trying to sort this out but I have no experience with the propane appurtenances and their functions as you know from the back and forth here on the forum. thanks Rich

Hey Scott, I fear your going to tire of this guessing game.I do appreciate the help. Not sure if it's been rich because unlike gas I've never seen any excessive black smoke, but it has been hesitating for some time. If it rains, I'll get to work in the shop tomorrow. I'll pull the air intake off the carb and check the choke position. The cloths pin is a new one but sounds good. we'll see if it will run better if the choke was closed. I just hate to pull the dist or anything else without some indication that I'm addressing the right end of the horse. Thanks again, Rich

(quoted from post at 16:55:15 11/07/08) Hey Frank, it will make some frost when you first light the engine. As the water circulates the frost disappears from the cover. What is queer is that if the engine dosen't light the vaporizor passes the propane through the hole in the metal cover. It may have been doing this forever and I didn't smell the propane. When I tried to cure my problem I realized that the vaporizor passes the propane if the engine dosen't light. The warmer the engine gets the less throttle you can apply until it begins to stall. I am trying to sort this out but I have no experience with the propane appurtenances and their functions as you know from the back and forth here on the forum. thanks Rich

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If the converter is leaking fuel when the engine is not running, that could be your problem. A leak in the converter may cause a lean condition because the leak may change the opening pressures. Depending on the brand and model, the opening pressure may be 1/2 inch water column or 1 1/2 inch. You may be operating on the leak only and the converter may not be opening at all.

These are very sensitive units. 1/2 inch W.C. is the amount of vacuum it takes to move water up a straw 1/2 inch.

Owen, thanks for the advice. I can say that the convertor does not leak any propane when the engine is not running, nor when it is running. I checked it with soap. It does leak off a quanity of propane if the engine is cranked and does not fire. After a few seconds of failing to start the fuel leaks out of the hole in the convertor's metal plate. I get where your coming from if the fuel is exiting out of the overflow prior to the outlet, maybe it's coming out because it can't get past the inside of the convertor due to some lack of vacuum not made by the cranking that is different than operation vacuum. Maybe acceleration demand changes the vacuum and eliminates the fuel out the bypass and I didn't see or smell it? I had to work and haven't had a chance to get back to my lift.

I'm going to check the choke possibility first. Something about Frank's idea that some carb spray should have made the engine pick up RPM's repeats my limited past mechanical experience. The fact that it did not, makes me feel that there may be a carb or choke issue. I am certainly not dismissing the vaporizor ( Convertor? )as the culprit. If it must supply some given pressure to that diaphram device on the side of the carb that it is not allowing, it could surely be my problem. But at this second my brain is stuck on the no increased RPM's from additional fuel in the air supply.

I did have the diaphram out of the Convertor. It had some debris, maybe fine rust or decomposed rubber. There are some alligator cracks inside, but no penetrations. The metal cover is stamped J&S, I think, if memory serves. It said .13 inches of water column among other things, I think. It's been a week since I read the thing.My plan is to check out the carb if that dead ends, I'll call Allegheny Clark Lift and see if they sell over haul kits for the Convertor. I've been looking on line for a service book, haven't found one yet. thanks for the info. Rich

Maybe-just maybe the vacuum switch on your carb turns on the fuel after the engine makes vacuum??? with-out seein' or knowin' what you have its hard to tell how it's set-up---if the switch on the carb turns on the fuel then there is a fuel selenoid in the line somewhere . I worked on the lifts at Maytag for 15 years and every brand was plumed differently-and different models of the same brand was different--some elect shut-offs--some elect with vacuum ---some vacuum only-------can you take pictures and post them??

If you can fnd a test port you could maybe rig a homemade manometer [do an image search] be better than shooting in the dark. Or if you have a friendly propane co. they might help test pressure. About where do you live?

I have had periodic frosting and then it goes away and runs OK for a while. Then looses power and eventually dies (wouldn't pull your cap off your head.) Ideas? Won't restart for a good while when this happens. Seems to be a fuel flow problem, but need to check the air as well.
I haven't checked for a fuel filter mentioned above, so will do that too. I assume you clean them as you would most felt filters? Thanks for any help you all can give me.... the tractor is stuck in the field as I write.

I have had periodic frosting and then it goes away and runs OK for a while. Then looses power and eventually dies (wouldn't pull your cap off your head.) Ideas? Won't restart for a good while when this happens. Seems to be a fuel flow problem, but need to check the air as well.
I haven't checked for a fuel filter mentioned above, so will do that too. I assume you clean them as you would most felt filters? Thanks for any help you all can give me.... the tractor is stuck in the field as I write.

(quoted from post at 09:34:18 02/06/10) I have had periodic frosting and then it goes away and runs OK for a while. Then looses power and eventually dies (wouldn't pull your cap off your head.) Ideas? Won't restart for a good while when this happens. Seems to be a fuel flow problem, but need to check the air as well.
I haven't checked for a fuel filter mentioned above, so will do that too. I assume you clean them as you would most felt filters? Thanks for any help you all can give me.... the tractor is stuck in the field as I write.

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Textrout, that is usually caused by either low coolant or a plugged line between the cooling system and the vaporizer. A propane engine like this actually uses the cooling system to warm the propane to keep it vaporized. As the propane flows through the hoses it cools them down and frosts them, staying in liquid form. It is kind of like vapor lock but in reverse. There should be a couple small hoses that connects to the vaporizer (which is the first thing that the intake hose goes to). If there isn't any coolant flowing here the vaporizer freezes up and you end up with little to no fuel flow.

You need to have your carburator and vaporiser rebuilt. over time the diaphrams and seals break down and have to be replaced, you will also get a buildup of yellow gunk inside that needs to be cleaned out. been running forklifts for thirty some years and anytime they get to running poorly rebuilding these two things usually cures the problem.

If I understand you right propane is passing out of the hole in the metal cover on you vaporizer. You could have a hole in the diaphram in the vaporizer. You can get a kit to replace all the rubber parts in there. Could be the whole problem