Outer Limits 4x4 Board

I have a 2F engine with 4speed gearbox in a 60series body (1982). It has almost 300k on the clock, and has had an LPG conversion in 1997 at ???km. It runs beautifully on LPG (although I use about 24l/100km around town). However, when running on petrol, I get a “flat spot” when I accelerate, especially after “engine breaking”, ie: slowing down with the foot off the accelerator. Someone once told me it is a leather sleeve in the carburetor that is wearing under the dry lpg. Is that true? Is it really the carburetor, and can it be rebuilt to suit the dual fuel for longer term?

Any hints greatly appreciated.

CruiserHead

What sort or carby are you running

STIKA wrote:What sort or carby are you running

Don't know. How do I find out? I am not that much of a techie person.

Thanks, CH

I have the same problem with my 84 5spd and have for about 6 months. A mechanic who is a family friend looked at it for me when it started hapening and said it was the sleaves and seals in the carby. The mechanic that rebuilt my motor about 15k ago said the same.
Both said it wouldn't harm the motor but if i got sick of it take it to a carby place. From memory a carby rebuild is $240 - 290. I was also told running mostly gas may only last 2 or 3 yrs.

I put it off because i was low on $. Lately it is hard to start on petrol (aparently accelerator pump in carby). The last 3 tanks of gas have done around 370km from 120 ltrs which makes your 24/100 look great.

I'll be ringing around tomorrow for prices and booking in asap to rebuild the carby, hopefully it will fix my problems.

I'll let you now how i go.

the flat spot could be any number of things..

are you running vacuum advance.. and if so is it connected straigt to manifold vacuum?

the reason i ask, is that i had a similar problem with the 308.. turns out that at idle, manifold vacuum is greatest and therefore there is a shitload of advance..

when you put the boot in, manifold vacuum drops markedly as does your advance.. i noticed that it didnt really matter with gas, but on fuel the engine would bog down..

light acceleration was fine because there was some vaccum present..

you will have your ignition advanced already if it is running sweet on gas.. i suspect you may have too much advance for fuel..

either that or there is something wrong with your accelerator pump circuit..

Yeah, it probably is a carb prob, 2 things can happen,from onle ever running gas.

1.)the diaphrams it the entire fuel system dry up and crack as there only source of lubrication is fuel.

2.)you recuire more air into the carby when running fuel and this may be causing it.

Thank you all for replying, especially Andrew81. If you get it done, could you please let me know what happened and how much you forked out? You are not in SA by chance? I have had a quote here of around $400....

CruiserHead.

Yeah i'm in Gawler SA. I'll let you know

you can get a carby kit for around 35bux pm rockhopper on this forum quite easy to rekit it yourself if you take your time and take photos so you know where everything goes but if your 40 has been running on lpg permanantly with only the very occasional then dont bother you will need a new one mine was all rusty inside the carby but i put a kit through it anyway and its no better with current fuel prices i only need the petrol as a limp to the servo fix so im not fussed id like to go straight gas but dont trust myself not to run out

pcman wrote:you can get a carby kit for around 35bux pm rockhopper on this forum quite easy to rekit it yourself if you take your time and take photos so you know where everything goes but if your 40 has been running on lpg permanantly with only the very occasional then dont bother you will need a new one mine was all rusty inside the carby but i put a kit through it anyway and its no better with current fuel prices i only need the petrol as a limp to the servo fix so im not fussed id like to go straight gas but dont trust myself not to run out

I take my 60series way past the last port of call for lpg, so I need the petrol option. I also like the increased power of the petrol when 4x4 driving, so I only use the gas for onroad driving.

thanks for the tip on pm-ing rockhopper. Maybe I'll take a look down the carby before I decide what to do.

CH

Hopefully a guy from work will be looking at mine next week. He's not a mechanic but about 50 and has always been in burnout comps, demolitions, that sort of thing. Has done some work for other guys from work and they're very happy with it and cheap too.
I'll keep you posted.