Hello,

Cam anyone help with this please:

I have had my 340 Redline (1.7) since new . It's only done 22,000ml and looks like new. However when I got it out of the garage last week it ran ok at first, but about a mile from home the engine started to drop revs, if I pressed the acelerator the revs would rise then drop.

I managed to get it home using the choke, with the choke out and the revs at 3,000+ the engine ran, but if I pushed in the choke the revs would drop again.

At home pushing the acelarator causes the revs to rise (stutteringly) reach about 3,000 and then die back pumping the acelaerator causes the enginee to "cycle" to 3,000 revs and die back.

It would seem to be the carburettor or fuel system, I belive the carb is a Solex twin barrel.

Has anyone any sugestions as to the problem as I can't drive the car to a garage the way it is.

Any help appreciated

I am sure the screws of your carburettor are loosened, there is the same problem with the 1.4. Check all fixings! Check also the flexible pipe between the fuel pump and the carburettor...

i agree on these, also check and clean the breather hoses.

Hugh

You can also have the same symptoms when the engine is running on 3 cylinders instead of 4, I had that. But I'm sure it's a problem with the carburettor here.

Thanks for the replies, the carb does not seem to be loose. Are there any problems with these carbs that I should check for?

The way the power justs dies when the revs reach 3,000 feels like fuel shortage, but the pump etc must be ok as the revs go to the redline with the choke, could it be somthing to do with one of the carbs barrels?

Mike.

it sounds like something is leaking air. are all the breather hoses connected properly?

Hello Mike,

I've had a 1.7 for 12 years and everytime it's had a problem the symptoms have been the same as your own. The first place to start is to remove the distributer cap, check that the inside is clean and dry, could be oil or water, are the contacts healthy looking? look at the centre contact it is sping loaded and twice my spring failed so there was little or no contact with the rotor arm. Once cleaned try the car again. Next comes air leaks at the inlet manifold, this was the problem that occurred just after buying my car, a Volvo dealer "replaced" the gasket for an extortionate amount, years later I took off the carburettor and found no gasket and an amount of "instant gasket", which I could have bought from Halfords for a few pounds! I got a mechanic friend to service the carburettor which also solved the problem 2 years ago! There is a little ball in one of the fuel injectors that can stick, the accelerator pump diaphragm can split also. As you can tell there are quite a few things to go wrong, I always start with the easiest. Good luck.

340 1.7s are famous for warping their carb bases, causing an air leak. Try spraying WD40 around the carb base (running but cold engine!)....if it runs ok during spraying, its an air leak.

You can either get the carb base machined flat again, or I saw some special thicker flexible carb gaskets on ebay a short while ago which solved this problem (without the expense of machining).

cheers

James

or just buy another carb - they aint too expensive or too hard to fit

Yeah, but be VERY careful that the new one isn't warped...at affects most 1.7s these days.

cheers

James

why do they suffer more heat than 1.4s?

It's the poor (cough cough Renault) design that can't handle the heat as well.

cheers

James

so's the b14 is it not?

Same problems with the B14... I just have changed the carb, I should start a topic with that, what a story that was...

I was about to say that the B14 is a tried and tested (read: ancient) design which had all these problems ironed out. Maybe not so!!

Volvo redesigned the manifold / carb setup for the Renault 1.7 engine for the 400 series. On injection models it was designed by Porche!

cheers

James