the modelj as we know (oldstyle) has the primer button on the side and the reed plate with the rubber square
the modelj new style has the primer button removed, i cant say about the inside of the new one but i'll make an assumption that it is the same as the oldstyle reed plate.

As for the cobra there is a valve plunger in the place where the reed plate is and it has a rubber button on the end of the plunger that goes into a hole. So basically the diaphram moves the plunger in and out of the hole.

there may be some other small differences but as for what i could see that was the biggest difference between the two.

Internally it is different, looks the same, same concept, no adjustments on the converter, more reliable

Internally it is different, looks the same, same concept, no adjustments on the converter, more reliable

How is the Cobra different from the Model J? Are there any adjustments needed when switching from one to another?

I was told that the state of Texas is going or is now requiring propane to be graded. But in this particular case, it was not a propolene (oily, waxy substance) issue, it was a over pressure issue as someone said in the impco buttin. Either way, I was already contimplating a cobra for the system.

John your point is valid, this is and has also been an issue in the proper performance of the forklift. One of the steps to properly maintaining an Impco LPG fuel system is to be sure that an LPG supplier is providing the proper grade of LPG. I was suprised at the response when I made several phone inquires to area suppliers inquiring as to what grade of LPG they supplied. Unfortunately, to my surprise, most of them did not know. Just as gasoline has different grades, so does LPG. Typically, in the US there are two grades, HD-5 and Commercial. While in most instances, the Commercial grade does meet HD-5 standards, this isn't always the case. We all have seen many times failure to use the correct one, can lead to negative effects on the overall life of the fuel system components of the forklift. This is why I always asked the end user of the problem plagged truck to check with his supplier to see what they are selling them and have them ask for verification of this.
Yes John, contamination is one of the largest causes of failure of a LPG fuel system. This is largely due to little monitoring of suppliers by the government, many of them don't maintain their storage tanks properly. This is why it's so important to perform regular maintenance of an LPG system. This needs to be done in order for the power unit to operate effectively and efficiently. I would suggest to an end LPG end user checking with their supplier and see how often they hav their storage tanks purged. If they can't tell them, then it may be in their best interest to check for an alternative sources.

Use to buy just the reed valves from SMH.Dont think they sell them ,anymore.without getting the repair kit.Ive seen this oil collect more in some regulators. seems like overnite.and not much at all in others.

Jplayer- you're right- the propane suppliers don't know nor care about what product they sell. I'm in the Phila are & can find only 1 vendor which can verify they sell HD-5 propane. All the other vendors say "propane is propane- what's the difference?".

I"ve notice since Intrupa & SMH have become 1 and now it's TVH- their model J regulators don't seem to last as long due to this reed valve issue. I can only assume they're making a cheaper product.

operator error is always a favorite scape goat for a mfg to sway the liability away from them. Sad but true...

i just recently had an issue with the same thing, bad converter, removed the cover and found a bent reed and damaged square rubber pad on the reed. This truck has been running for years though with no issues till now. The one thing i noticed and have noticed in several converter changeouts is the amount of oil accumulating in the converter from the LP Gas. This oil is very damaging to any rubber/neoprene parts and will emminatly cause failure.
The only fixes i know of to cure this problem is:
A) to be continuously cleaning the converter at every PM service(mfg's and dealers alike are suggesting this as part of a pm now)
B) Change LP Gas suppliers

Apparently not all LP Gas suppliers are created equally, some have more oil content in thier lpgas than others.
They dont want to see it as an issue apparently.

This truck has a vacuum lock, I'll change it over to cobra and tell them to warm up the truck, thank very much for all the valuble imput

I also have found that electric shut off valves seem to damage the steel reed assy. I have changed a few trucks from electric to vacuum shut off & the problem so far has not returned.

Hi J & C;
The primary cause of this problem is operator error. This is what Impco says in a Service Bulletin they issued some years back. Starting an engine in extreme cold to move a vehicle a short distance, and stopping the engine without warming the coolant can result in trapping liquid propane in the heat exchanger. As this liquid vaporizes with the engine stopped, pressure in the heat exchanger will rise until excessive force is applied to closing the primary regulator valve against its seat. If this is occurring frequently the primary valve in the vaporizer regulator may become damaged.
Other items to look at are:
1. Water level of radiator
2. Vaporizer mounted higher than upper "radiator hose"
3. Defective radiator cap
4. Restriction in water lines (ck flow restrictor at reg.)
5. Water pump defective
6. Improper, missing or defective thermostat

We have been seeing the same thing. One of the issues is the grade of LP fuel that is being used now it is not as clean as it used to be and the least bit of tar build up creates the higher pressure and bends the reeds. Once solution we have found is to replace the J with the Cobra seems to hold up better.

Does this have an electric lock off? The Daewoos that had the Impco regulators with an electric lock off have this problem. I think it is from the pressure in the tank rising higher than normal and then when the lockoff pops open to start it causes some sort of pressure surge that damages that steel reed valve.