Need help with Solex! Quick!

Post by **foggyjames** » 13 Sep 2004 10:44 pm

If there is insufficient (or too much) fuel in the float chamber due to the absense of this hose....then it may well be related.

cheers

James

Post by **Juha** » 15 Sep 2004 07:52 am

pettaw wrote:I'm 95 % certain its the ventilation hose from the top of the float chamber. If you look on the side of the top of the carb, there will be a place for the hose to just push on and then it just hangs round toward the back of the engine, presumably if it overflows then it directs the petrol down the back of the clutch housing rather than all over the red hot engine.

A garage pulled ours off the car and it was a year before we noticed it and put a new piece on it.

Could you show me from the picture where the hose should be connected?

Post by **Juha** » 15 Sep 2004 08:00 am

foggyjames wrote:If there is insufficient (or too much) fuel in the float chamber due to the absense of this hose....then it may well be related.

cheers

James

The problem is... Sometimes when I accelerate fast or when I try the top speed of the car, it suddenly loses almost all of it's power and starts coughing.
I can still accelerate slowly when I floor the gas pedal. If I stop, it's very hard to get moving again. I have to use very high revs to get the car moving. The way to get rid of this coughing is switch to neutral and give the enginge so much gas that it revs up to 7000rpm. When I do that couple of times, all goes back to normal.

Post by **5lab** » 15 Sep 2004 08:39 am

check yer valve clearances

Post by **foggyjames** » 17 Sep 2004 01:59 am

Juha wrote:The way to get rid of this coughing is switch to neutral and give the enginge so much gas that it revs up to 7000rpm. When I do that couple of times, all goes back to normal.

That is the standard procedure for 'de-flooding' - so I've got a tenner on it over-fuelling due to this probable float chamber problem.

For what its worth, revving to 3000-4000rpm ought to be sufficient to blow the excess fuel out - 7k is seriously pushing the boundaries of what the bottom end (mainly rods) can handle. A friend has held 7500rpm a number of times by accident in his B18U engined 440 (pretty much the same engine as a B172), but that's certainly not to be advised!!

cheers

James

Post by **5lab** » 17 Sep 2004 07:28 am

440s have rev limiters on them thou, a 340 will just rev till it dies

Post by **Juha** » 17 Sep 2004 09:15 am

foggyjames wrote: That is the standard procedure for 'de-flooding' - so I've got a tenner on it over-fuelling due to this probable float chamber problem.

For what its worth, revving to 3000-4000rpm ought to be sufficient to blow the excess fuel out - 7k is seriously pushing the boundaries of what the bottom end (mainly rods) can handle. A friend has held 7500rpm a number of times by accident in his B18U engined 440 (pretty much the same engine as a B172), but that's certainly not to be advised!!

cheers

James

So I've got a problem with the float chamber and I should take the car to the doctor?

I know that revving up to 7k is really not good for the engine, but it's the only way to stop the coughing....
I'll just have to get in touch with the local carb expert...

Post by **foggyjames** » 19 Sep 2004 11:27 am

5lab wrote:440s have rev limiters on them thou, a 340 will just rev till it dies

If this one didn't kick in by 7500....i don't think it was going to! Carb 440s won't have one either. A 360 GLT supposedly has one too....but I know people that have taken them to 7000.

Are you sure that a longer time spent at, say, 4000rpm wouldn't have the same result? If you're not sure what you're doing, I'd definitely take the car to a mechanic.

cheers

James

Post by **pettaw** » 19 Sep 2004 11:57 am

It lookas as though the hose is already connected correctly. One end connects to the carb, and the other just hangs down the back of the engine block down past the clutch bell housing.

That hose is not your problem anyway. ITs just s safety thing so if the float chamber really goes then it directs the fuel away from the hot engine.

I would strip the carb down, paying particular attention to the full load enrichment diaphragm and the accelerator pump diaphragm, making sure they're not split and also the float chamber adjustment height. Unclip the float and take out the needle and make sure it isn't totally worn out, a small line of wear is fine and indicates a good seal. Very good instructions in Haynes.

Before you take the mixture screw out to clean it, check the number of turns its adjusted to by screwing in all the way until it just stops. IT should be about 2 to 3 turns. Also check the carb base for warping between the base flange and the metal base, remove the flange and check with a straight edge. Also check all the breather hoses and make sure they're absolutely clean, blow through them with carb cleaner.

Once you get the carb back together and on the car, check for air leaks round the base, using an unlit butane torch or WD-40, wave it around the carb base, round the throttle assembly in the carb body and round the inlet manifold gasket, there should be no change in engine running with the engine idling. Be careful with these substances as they're highly inflammable.

I'm sure your problem will be found somewhere in that procedure.

Post by **Juha** » 19 Sep 2004 05:23 pm

foggyjames wrote: Are you sure that a longer time spent at, say, 4000rpm wouldn't have the same result?

Well... I'll just have to try that when the coughing surprises me again...

foggyjames wrote: If you're not sure what you're doing, I'd definitely take the car to a mechanic.

I'll do that...

Thanks everyone!