Hello!I have a 340Dl(1990) with a 1,7 petrol engine,solex carb and i'm having some trouble whit it. When climbing steep slopes
or when the engine is working above 2700 rpm for about 30 sec to 1 minute,it falls on it's nose,backfires then runs normal if i let go of the acceleration. When climbing steep slopes it dies after backfiring and it starts very hard,and if i put it in neutral it just dies without backfiring...Someone pls help me!!!When runing on flat or under 2700rpm it runs normal and starts fine

Have you checked for a warped carb base / air leaks?

Sounds like the carb if its struggling under strain.

it could be just because the carb is absorbing air from somewhere else than it should?????? last spring i refited the carb on the engine and maybe that's when it happened.....I was having problem with steep slopes before but not every time......like i do now...if that's not it what else can it be???? A mecanic sugested that the engine receives eighter too much gas less than it needs....it's one or the other........how can i find out what's the cause.....??? air or gas.....???

Hi outlaw.
Are your gaskets ok when you refitted the carb?
Are the bolts all tight on the carb?
Cheers Mark.

Check the floats in the carb are set at the correct height and that the chambers are not flooding. (gas)
Or for air leaks (Air).

The sleep slopes suggest higher strain on the engine, im not sure the slopes themselves are causing the problem. Maybe just the increased strain on the engine?

One additional thing to test, try if it does that when you drive petrol tank cap open.

Thanks all for answering on such short notice,and yes it does that when there's a higher strain on the engine,when i,m trying to overtake someone( as i said above 2700 rpm).All of you handed me some good ideeas .....alt that is left to do is to start working
Thanks again
PS :Ifitted new gaskets on the carb when i mounted it on the engine last time

i had the same backfiring thing everytime i tried to get upto speed quickly and it turned out to be carb gaskets
kev

Another cause can be oil in the distributor cap, but tends to stall when pulling off at junctions more. Sudden choking when applying power can mean a weak spark is being drowned by fuel.