Alternative Fuels

We've got a forklift we just acquired with a Ford 4.9 I6. It currently has a Model J vaporizer and a CA125 Mixer.

The engine misfires and bogs down when going up hill unless we push the primer button on top of the vaporizer. Is the Model J too small of a vaporizer for this engine? Mixer too small? I have a Model E on the shelf I could swap in if it would be the appropriate size.

Any suggestions are welcome.

Thank you,

Brandon

A J will flow enough fuel for approximately 100 HP. From the factory the Ford 300 L6 is capable of producing anything from 114 HP to 170 HP. None of this means the J isn't big enough because you don't actually tell us what rpm the 300 is pulling when the problem occurs.

The 125 will flow approximately 235 cfm which is enough for a low rpm 300 L6. By low rpm I mean no more than 2500 rpm, 3000 rpm will push the 125 past its cfm rating.

So to help us help you please let us know what rpm the problem is occurring at.

We don't have a tach on the motor but theres no way we're exceeding 2500 RPM.

It only bogs down when its under a heavy load until we push the primer button on top of the vaporizer. It'll bog down at any RPM when under a load.

I only ask about the model E because it's what I've seen on all the converison kits.

Perhaps a mis-adjusted lever of the membrane in the vaporizer?

I'd suggest checking (servicing) the LPG installation. If the engine isn't going over 2500 rpm it sounds like a poorly tuned/adjusted system to me. I'd start, as BigBlockMopar suggests, by making sure the J is setup properly then check the 125.

Fitting the L is an option but maybe not the right option. Do you know the condition of the L?
You could fit the L to totally replace the J but you wouldn't learn anything about servicing the regulator doing that.
You could fit the L to make sure the 125 isn't the problem (i.e. the 125 won't let enough fuel flow) because a properly functioning L will certainly flow enough fuel for your 300 L6.
You could fit the L while the J is off being serviced/repaired/rekitted so your forklift isn't out of action and if the J is found to be unserviceable just leave the L on it.

I don't have a L on hand. All i've got is an E.

Would an E be oversized? Is that possible?

Sorry I meant E but kept typing L.
Can a regulator be oversized? I honestly don't know but I suspect they can. It makes no sense to me at all to make multiple regulators that each flow different amounts of fuel that support different HP levels if 1 big one will work for all mixers without any problems. I think the sensitivity of the regulator would be adversely affected if it is used with a mixer that is either way to small or way to large.

Okay. I’ll put in the model e and see what happens.

One thing I was thinking about is the mixer only about half a turn from being set all the way rich as far as fuel adjustment goes. Maybe it’s not getting enough fuel which is causing me to set it so high?

Could be way off with that one

All valid comments ahead of this post. The 300 would stretch the capability of a J though. The problem is the fuel is taxing the capability of the reg to vapourize enough fuel. Your comment about pushing the primer help indicate that there is a problem with the J. A primer button is meant to depress the secondary diaphragm to assist starting but once the RPM is increased and load applied the primer should not even be able to reach the diaphragm to help. Either the secondary lever is set wrong or there is a hole in the diaphragm. Possibly a leaking primary seat but unlikely. The 125 mixer should be able to handle a forklift. Personally, install the E. We used E's on all of our conversions on everything from 4 cylinders engines all the way to the BB. J's were used on small 4 cylinders on FL or 1 - 4 cylinder gensets. On 4 cylinders the engine definitely needs a primer but once running the E functions normally. I would also open the power valve on the mixer to at least 3/4 or maybe even wide open on an engine that is 300 CI. Don't be afraid to experiment with this adjustment.

Pardon my ignorance but is the power valve the flat head knob with the big head under the mixer diaphragm?

Power valves, if they are part of the mixer assembly, are usually located either on or directly opposite the fuel vapour inlet.
The 125 is likely to have a separate power valve assembly which will be located in the fuel inlet hose and look like this Screw the bolt in to lean the power mixture, screw it out to richen the power mixture.

All power valves do on basic LPG systems is limit the total amount of LPG vapour that can enter a mixer, they are not like a petrol carb system that comes on slowly to feed in more fuel as engine vacuum drops.

On a 125 mixer the power valve is an integral part of the mixer. It is located at the vapour inlet on the bottom side. Its the silver adjuster with a small pointer on it and has 2 wrench flats. Probably 1/2 inch(13MM) wrench size. The mixer will have an R and L stamped in it indicating Rich and lean. The typical 50 series all the way up to the 225 series IMPCO mixers have the same design for the power valve. Just turn the valve pointer toward the R. The IMPCO power valve is basically a blade inside the opening with 90 degrees of adjustment. It will only control the mixtures if the load is 75%-80% or higher and if RPM's are near max. It will not affect or have minimal affect on the light load areas as that is controlled by the internal gas valve which is a fixed value based on airflow.

On a 125 mixer the power valve is an integral part of the mixer. It is located at the vapour inlet on the bottom side. Its the silver adjuster with a small pointer on it and has 2 wrench flats. Probably 1/2 inch(13MM) wrench size. The mixer will have an R and L stamped in it indicating Rich and lean. The typical 50 series all the way up to the 225 series IMPCO mixers have the same design for the power valve. Just turn the valve pointer toward the R. The IMPCO power valve is basically a blade inside the opening with 90 degrees of adjustment. It will only control the mixtures if the load is 75%-80% or higher and if RPM's are near max. It will not affect or have minimal affect on the light load areas as that is controlled by the internal gas valve which is a fixed value based on airflow.

Learn something new everyday, thanks C3H8

How did you go with this Lynnmarine?