Mick1950

hi fantic. mick from England here. hope you are well and i guess enjoying the snow at this time of year. dunno why (4 months later) but the problem has started again! just to refresh.....if i switch to petrol it runs perfectly well. if you count in seconds ie 1,2, 1,2 etc.....the surge happens on 2 each time. it gets worse on load....ie going up an incline and is more prounounced from 0 to 60. above 60 it`s still there but not as noticeable. i did source and put in the manual T valve you suggested way back in September. any more ideas? oh, by the way....i ran it out of gas last week (after the problem started again) and then took the filter bowl apart (as in one of the pics).I expected to find it full of liquid and a diaphram filter which i would have to clean.....but didn`t have a clue what the hell was in there!!! so put it back together. any ideas? Cheers Mick

Rmart30

Not sure what type of carb setup you are running but the Impco systems have a adjuster for setting the fuel on them. Its right under where the lp gas goes into the carb.
With help from a friend put it under a load and adjust it till it hits its highest rpm. You will hear its rpm fluctuate when you move the adjuster.
Have you tried to look up a manual for it online showing the adjusting procedure?

fantic238

Hi Mick. Thank you for posting the PM on the forum so we can share the info with the others.
The surging is a pressure problem, now up tu us to understand wether the problem is in the high pressure circuit (tank to reducer) or in the low pressure (reducer to diffuser).
First of all, i need to know if you have it surging on idle too, or if the surging is dependent on the rpms, acceleration etc.

fantic238

In the meanwhile here is the link to the old thread:
https://www.cherokeeforum.com/f2/surging-lpg-24984/

Mick1950

Hi Rmart, thanks for your reply...really appreciate it and all stuff noted. fantic, it doesn`t surge on idle but as soon as i pull away it surges. the surging continues and is really bad upto 50 mph. the faster i go after 50 the less noticeable it is. however, if i am going uphill at 50+ (ie under load) it becomes worse.

fantic238

Ok it is definitely a pressure problem.
Try the following: inflate the tank with an air compressor for 5 seconds, using a small piece of rubber hose in front of the nozzle, when the tank is half full.
Then, when the engine is hot, turn it off and unscrew the little black cap on the bottom of the reducer, some black oily stuff should come out, let it all out then put the cap on again.
With a piece of duck tape close the air inlet of the air filter, about 30% of the surface and go test drive and let me know.

fantic238

There:

Mick1950

ok, will do. thanks.

Mick1950

Hi fantic. sorry, have had to deal with a family bereavment so haven`t had time to look at the problem. Just looked at your instructions again but do not understand how i get compressed air into the tank without having a nozzle the same as the LPG one.

fantic238

If you have a compressor with the classic gun
you just need to press it with a little rubber o-ring or similiar against the filling hole where the little ball is and it will work.