Running on lpg only

Alright all I've got a 2l golf gti in my 73 westfalia which runs on 100% lpg. It has 2 tanks but when running on the main tank it stutters under power and loses power on hills also , if I flick the switch to the reserve tank it goes great with no problems. The garage wants to put a new main tank in hoping at will sort the problem has anyone else got any ideas before I go that way
Thanks tony

 

swap the hoses over and see if it does the same but in reverse....(not driving backwards, obviously)

 

Is LPG ok for engines...what are the issues?

 

I hope so, have ran an air cooled T25 on it for six years!!

 

very few tbh...heads, valves and valve seats need to be up to the job and timing often needs to be adjusted to account for the difference in burn times, but it's a mature technology

 

Yes back the timing off abit...so it still runs ok on petrol and off you go. No problems in the six years. Just one big saving

 

I ran it on my old 1600 and never had problems. Always cheered me up paying 50 odd pence a litre shame I can't do it on the new one means I have to think about the cost of going places now

 

It's not all sweet and nice ....it's very dry so most modern cars would run an oiler . It fooked chrisradiomans type 4 motor .....you loose 10 % bhp