3.5 v8 on carbs petrol wont work properly

My 3.5 v8 carb runs both petrol and lpg but on petrol it will not idle or run properly and makes really loud back fires, it sounds really terrible asif its only running one carb but then on lpg it runs fine except it smells alot of gas out of the exhaust, does anyone have a clue?
Cheers steve

It needs a service, tune-up, timing check and a visit to an lpg specialist

if its strongburg carbs , check the diaphrams
just a thought

Its su carbs

I had similar issues with mine (but no lpg)
It was in the end a small piece of paint/plastic lodged in the inlet valve of one float chamber.

Was that causing it to kind if flood?

Not entirely sure tbh. This is my 1st v8 and am a novice with these things.
It did however make it run terribly; not able to rev, with some popping and banging on what was left of the overrun.

I have not really finished checking it all out as I am still doing the rewiring, although I just have to do the 'fusebox' now.
Hopefully will be running on the road this week.
:car:

Sounds like you have a v8 like mine mine needs fully rewiring next lol

compression test- suspect head gasket across bores

Only just been rebuilt there is no problem on gas

SU Carbs.....

Ok, here's a little story.

I lived for many years in The Netherlands (Holland) and they have been using LPG for donkeys years. One of the biggest problems with the old installations (pre-1990's) was that people used LPG as their primary fuel and petrol as a reserve. The car was started and run on LPG and, like I said, only switched to petrol when they were out of gas.

This resulted in the carbs running without any lubrication (Petrol) and, in the case of SU (or similar) carbs, means that the needle and jet wear excessively resulting in a very rich mix when they are eventually used on petrol. It doesn't take much to wear them out. In my case I hadn't needed to use petrol for almost six months, and when I did, you could see the needle on the petrol gauge going down (almost).

Anyhow, newer LPG systems (from the mid 90's) now start the car on petrol and switch over to gas automatically so the carbs and there parts get lubricated. At least the systems in Holland do. Never had LPG here in the UK.

If the if the SU carbs you have are similar to the ones used in the original Mini's (showing my age here) then they are easy to strip and clean. Parts are cheap and it's a fairly simple process to do it yourself. The ones I have seen on all the project threads certainly look similar so you should not have a problem.

Lovely carb. Very simple design. Very reliable. Easy to adjust.

Hope this helps.

Vic.

Hey vic your example sounds like it when i switched over to petrol after a long time (starting on gas) it would not work then i had a new engine put in but carbs left and i still had this problem, so if i buy a rebuild kit should it be reasonably easy to rebuild them?
Cheers steve

If you have a little mechanical sense (you've taken things apart and gotten them back together - working) then it won't be a problem.

If you have no manuals for the carbs, make sure you take pictures as you strip them so you know where all those little screws, washers, jets etc go when it comes to putting it back together.

Going back a few years to the early gas installations in Holland (early 70's), they just used to punch a hole in the air filter housing and stick the pipe from the evaporator in to get the gas in the engine. Volvo's were especially good at blowing up air filters due to backfires when starting on a cold morning.

Vic.

Do you know how to tell what carb they are vic?
Steve

Should be a type/model number stamped on the body somewhere. Otherwise Rave may have the details you need, or, even a Haynes manual, though they usually tell you to "remove the engine" before you do anything.

I would have a look at Rave for you but I'm away from home this week and I don't own a Haynes manual.

As a last resort, pop in to your friendly (?) local Landy dealer (parts department). I find the parts guys are usually pretty good and will take the time to look things up for you. They may even have the refurb kits.

I don't have a carb V8 (wish I did) as mine's a multpoint injection jobby.

I miss me carbs I do. Even the bikes got more computers on board than an early nuclear submarine.....

Vic.

Ok,

Just did a quick search. There is an online Microcat catalog (in Russian & English) that may help. Try Microcat - Spare parts Land Rover catalogue in English

Vic.

You can also try:

SU Carbs ? Your S.U. and Stromberg carburetor authority & SU Carburettor Links and Info Main Page & also SU Carburetters Home Page

The last link is to the SU carb company and they have refurb sets you can order online. Also have an easy selection system.

They may be able to help you get sorted.

Vic.

Well you see my carbs are from a rover sd1 which makes life a big pain :-/ but i shall look over your links vic thank you