Forklist carby stuff Questions`

As Ive mentioned a week or so ago...I have a Impco CA 50 Carby and a
Mod J evaporator on my forklift.
It has a seperate tube to engage the "lockout:" part of the
evaporator..IE..if there is suction on the seperate then
feeds propane to the carby.
I discovered today..that if I push and HOLD the "primer"
will run just fine.
So that lead me to think the "lockout" part of the evaporator was not
So I sucked on the hose..and nothing happened. HOWEVER....If I BLOW in
the hose (just a few pounds..and no smart comments here
thankyouveddymuch!!) delivers propane to the carby and it runs
What the fuck?????
I can detect little or no suction at the "lockout" tube attachment on
the carby...and no blow either. I do have good suction at the
entrance to the carby while its cranking.......
What the fuck (again)????
Do I have a problem with the evaporator..or the carby?
No suction noted by finger tip on the suction line at the carby.
Thrice WTF?
All the seals and diaphrams are ok, with no leaks noted. Both the
carby and the evaporator appear to be nominal...visually.
Is there a way I can bypass the "lockout" portion of the evaporator
and simply run it that way? I do have a 12 solenoid that I can add to
shut off the fuel in case I leave the tank turned on over night.
Im rather lost here.....which since the something Ive had
some experience with..damnit.....
The diaprhram on the inside of the rear cover on the Mod J has a
triangular bit of sheet steel attached to it. It rocks on a piviot
point on the rear cover and pushes down on a spring loaded valve. This
bit of triangular steel was bent over the pivot point. All the
diagrams show it to be I carefuly flattened it out before
discovering the above data..but yesterday it DID run with the primer
button depressed.....if that helps in the diagnosis.
Over the years...Its gotten worse and worse...I had to prime it (push
the button) to start it..often several times before it would fire up
and run I suspect this is part of that ongoing issue. Ive seen
few forklifts be a problem to start on propane when there was good
compression and good spark.
This thing only has less than 1800 hrs on the Hobbs meter...but it was
made..I the early 90s.
Reply to
Gunner Asch
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Do I look like I have a Forklifts-R-Us sticker on my forehead?
Tried yet? (Must be Brit-based. ;)
Reply to
Larry Jaques
I think I'd look at two areas. (1) what does the primer do that allows the thing to run and (2) where does that vacuum/pressure line connect to at the engine end. From that you ought to be able to figure out what is going on and correct it.
Reply to
John B.
Doggonit I'm a "carburetor modifier" even and I have no-idea what you're talkin' about, G. :/
Alvin in AZ
Reply to
What...I didnt make it clear? My forklift has a carberator..and a pressure regulator (normally called an evaporator). It has what is called a "lockout" in it. This lockout keeps the evaporator from giving any fuel to the carby..unless there is suction on a port on the body of the evaporator. Just a few ounces of suction opens the evaporator and allows it to supply fuel to the carb. The suction is provided by a connection from the carby to the evaporator via a short when you crank the engine..a little bit of the suction that happens in the carb is also applied to the evaporator through that hose..letting propane flow into the carb..and then starting the engine.
What I have is no suction on the carborator port..and ..and..when I apply suction to the evaporator..nothing flows. Only if I apply PRESSURE to the evaporator does fuel flow. Blow into the suction (vacuum) line..and it opens the valve and voila..fuel.
There is a button on the evaporator unit that is a "primer". When you press does something inside and it allows fuel to flow into the carb without suction. So you dont have to crank it for 10-15 seconds before the engine starts. Press the pushed out propane directly to the carborator. Kinda like a choke or gas shutoff override (which it actually is) floods the carb with a big blast of propane so it doesnt have to crank very hard before it starts.
So when I press the "primer" button..and hold it..the engine starts right up, but the moment I let it go..the engine dies because the evaporator stops allowing fuel to flow to the carb.
So I have something wierd with the evaporator/carby..two requires pressure to allow gas to flow out of the evaporator. when it should be a vaccum......and the carby isnt supplying any vaccum..or not enough.
Many of these engines dont have an evaporator with a "lockout"...that vaccum line that allows propane to flow only if there is suction on that port. They use a electrically operated valve. Turn on the key..and it opens up the line from the propane tank to the evaporator..which allows fuel to immediately flow through it.
The evaporator btw...does several takes the 380 psi from the propane supply tank..and regulates it down to about .5- 1.5 pound pressure...and because there is a very cold liquid flowing through it...has radiator coolant running through the back of it to keep it warm and not freeze over. When the coolant gets heats up this evaporator pretty good...and make the change from a liquid to a gas even better.
Is that clear enough now? I can tell you.
Gunner, on his way to LA
Reply to
Gunner Asch
I talked to a friend about this the other day. He asked if you had a picture of the unit. That they are usually real simple to work on but that adjusting them without a good water column gauge is a PIA. He asked if yours had ever been adjusted?
He did mention that a good replacement if yours is bad would probably be a Beam T60.
Reply to
Steve W.
The evaporator is an IMPCO Mod J. A buddy in LA gave me one today and Ill hook it up this weekend and see if it fixes it.
Reply to
Gunner Asch

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