22r propane help

Yotanut · Jul 2, 2017

Truck was running fine. Ran a tank empty. Swapped to other tank would not run. Filled up original tank and truck ran but seemed to have an erratic miss Parked truck for a couple of weeks now truck turns over but will not crank. Maybe I sucked trash into system when I ran tank empty? Anyone done a gasket/ diaphragm rebuild on a mixer and evaporator? I noticed a hissing / pressure relief sound from evaporator after trying to crank it and evaporator seems to be freezing up some just from multiple starting attempts

paradisepwoffrd · Jul 2, 2017

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Elec or vacuum lockoff? Any filter inline ?

Is there a button in the center of your evap/reg? If so push that button with the fuel lockoff open and itll purge fuel to the engine.

The converter shouldn't be freezing up unless you dont have coolant flow to it.

Maybe try cracking the lines at each location to verify fuel? Make sure to wear gloves and use insulated tools. Liq propane will burn you.

Try starting it on ether to eliminate the ignition?

ROKTOY829 · Jul 3, 2017

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Check the coolant level, low coolant will cause it freeze up.

Check spark, propane has to have a strong spark.

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paradisepwoffrd · Jul 3, 2017

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X2 on checking the plugs. Propane can foul out a plug and not visually tell.

ToyotaTom · Jul 4, 2017

Both my mixer and the evaporator developed a leak over time. Pop them both open, clean them and reassemble with some sealant. While you are at it check all your vacuume lines and make sure your mixer is all all tightened up to the manifold.

hhc · Jul 4, 2017

what style fuel shut off? is it a impco system? check for good spark also check your vacuum lines. the vaporizer has a shut off built in that needs vacuum to turn on (depending on model it will have a separate line or it will need vacuum in the larger fuel line to your mixer)

also when you said switched to the other tank is it a dual tank set up? electronic 3 way valve? if so there notoriously bad in propane systems try going straight from tank to mixer.

i work on large stationary nat gas engines for a living and take care of lots of v8 propane gen sets, mostly just lurk here but post up what you find ill try to help however i can.

Yotanut · Jul 7, 2017

I don't see a purge button on evaporator it is a impco 100 system from Nash lift trucks. Spark checks good. Vacuum lines seem good. It is a vacuum lock system. I have propane going into evaporator from tank. Truck cranked maybe 2 times out of 10 and ran for just a second I assume the top pic is of a filter? I assume in the bottom photo the part on the left where the pane comes in from the tank is the lockoff valve? part on the right is the evaporator?

ROKTOY829 · Jul 7, 2017

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I just about bet you have a bad evaporator. The impco are so so. I have installed new ones out of the box that were bad. Try some brake clean and spray it in the engine and see if it run off of it.
Take a picture of the carb. Make sure the diagram or piston is moving in the carb. I bet your's will have 4 screws holding thr plate on.

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ROKTOY829 · Jul 7, 2017

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Also on that style evaporator, there will be a plug. You can remove the plug to test pressure. Use a vacuum/fuel pressure tester and check pressure. 2.5 psi.

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