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Solex B30 PSE1 Leaking fuel upon stopping engine


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I am a. Little frustrated... having just paid for a professional restoration of a b30 PSE1-1 for my herald 1200 , it came back looking better than new. So imagine my disappointment  when after fitting and a little fettling, i stopped the engine and found petrol squirting /dribbling out of the accelerator pump swan neck and also the main opening in the middle of the carb throat. It was enough to produce an intermittent drip from the throttle spindle directly onto the manifold. Also some made it past the throttle butterfly and out of the manifold drain.  

Any ideas where to go looking for the issue? Or should i just revert back to the Weber 32-ICT that had been fitted previously?  The problem with the Weber being that the throttle mechanism would never return cleanly to idle, car often difficult to start from hot and fairly poor economy. I thought that by returning the car to a correctly specced carb i was doing the right thing.

The Solex carb has been assembled with a plastic float and a fairly thick washer under the float valve.

Upon first fitting, the float valve jammed open causing a lot of petrol to flood the carb. I took the  valve out, gave it a good blow through, checked it for correct operation and refitted.

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did you flush the supply pipework into a jar?  its quite possible you have some dreaded rubber slivers jaming the  back float valve

these little sods are born when you push a hose onto a metal fuel pipe 

what you are seeing used to be called perculation ,  and can be down to a number of things

so 

rubber slivers

top cover gasket blocking air bleed holes 

float problems raising levels 

ball and spring missing  from th accel pump swan neck

blocked air flter

just some ideas,  where was the recon done ??   

its the insides that matter more the looking pretty 

 

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Hi thanks for the reply. 

I agree, with your comment about the physical appearance. The carb was repaired by classic fuel systems in Bradford. It does seem to have been done to a good standard. It could of course be the rubber slivers, but yes i did purge a little fuel before connecting to the carb, although the fitting to the carb itself has a stub of about one inch , and that might have caused a few slivers i guess.

 

I have an adjustable filter/pressure regulator fitted and set to just a tad over 1.5 psi. 

So ... check gasket isn’t covering any holes first?

then remove the float valve again, emulsion tube and main jet? And clean out?

 

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There were a few tiny bits of black (hose rubber?) in the bottom of the float chamber. I have cleaned these out.

none of the body holes are obscured by the gasket except for top middle of float chamber but that has a notch cut out of the body below the gasket.

Given that there is what i think is a vent to air in the top cover, i am wondering where the pressure is generated to push the fuel through when it is stopped and hot. Could it be a simple as an incorrect float level? It was coming out of both the accelerator pump swan neck and the main bridge. 

When full of fuel, the float is sitting proud of the flat surface of the carb body by a few mm.

Although the photo s upside down... the accelerator pump mechanism is clearly very close to the manifold ... should i raise it up onto a thermal block of a few mm to reduce heat transfer.

 

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you can get heat boil the float fuel when air flow and such stop when you cut the engine this can give you bubbling

maybe a heat shied under the carb /flange   as many other makes used in the day  may help 

you could make one from sheet steel /ally  plate   to mask heat from the exhaust/engine  to dissipate  thermal transfer  

a cheap diy would be simple and easy to see it it helps 

even as a test a good folded piece of cooking foil across the manifold zone   to baffle heat from the carb might give you a clue 

Pete

 

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I think you are on the right track with heat transfer, expansion and especially boiling. Modern fuel has a high vapour pressure than of old, partly due to ethanol content, meaning it vapourises/boils easily. Or at least some components of it do, which is also why it goes off so fast.

Float level may be a bit high, adding to the issue, but not necessarily.

Insulating block between manifold and carb may help a bit. Could add a carb cooling fan if really keen....

Nick

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i had a new pug 405 which had a lot of supposed vapourising  hang ups  so they fiited a sensor and a cooling fan for the carbatootie which used to switch on at 2 am in the morning , cold engine   but noisey  thing woke up half the household   out to the garage ( from the house ) an pull the plugs  PSA didnt understand and kept faffing around so after less than a year old she went.    the end of a  brilliant car rubbish dealer .

but yes carb cooling fans are out there   got the Tee shirt   Ha !!

Pete

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I will be trying the heat shield idea. And also i think i can get away with about a 5-7 mm  gasket to try to prevent thermal transfer without needing new studs.

in the meantime, the damn thing is runnng rich at idle and the volume control screw isn’t working! I guess that i must have picked up some particles so it is back to strip down clean and reassemble first. 

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the idle circuit only works with a correct idle setting of the throttle plates if for some reason the idle is screwed in too far and the idle is artificially high the 

volume screw will have no effect ,  check this first    the slower the idle the more effect on idle mixture setting response 

the screw only adjusts the idle mix it has no effect on the main jet running 

also check the slow running jet in the side is not blocked  the hex headed  jet in the outside 

Pete

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Latest news in the saga... I have removed stripped, cleaned and reassembled the carb.

now re-mounted with a thermal spacer to reduce heat transfer.

Got it idling very well but with volume control wound almost all the way in. Does this mean an incorrect idle jet?

Just checked the plugs and it was very sooty. Hoping this is from all of the fiddling on the drive.

Will take for a quick run... do i need to be concerned or just get on and enjoy it?

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most idle   slow run jets are 45s   not easy to clean as a careful prod with a wire pokes any debris inside the jet body ( this is the one on the side )

i would say from lightly nipped up that 1.5 turns out would be a good start point 

blocked slow run jets normally make for a lumpy stall or needs a over fast idle to run , doesnt affect performance just makes progressive power  all or nothing driving 

the air bleed to the back of this jet is from the small hole in the top face , might help if this is tested for being clear along with the small holes at the side ogf the throttle plate which is where the slow run exits into the throat  the other small holes in the throat near the T plate is the vacuum for the dizzy  feed ,

all need to be clear to  run smoothly 

Pete

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Thanks for all of the information. 
I have blown through all I could find and didn’t see anything obvious.  The idle jet seemed to be clean as a whistle. I did note the very slightest of ‘edges’ when I ran a finger nail along the volume control needle. 
 

on short test run all good for couple of minutes and then threatened to to cut out and needed a bit of choke to keep revs up. Came back home to have a think about it some more 👍👍😳

still got a very definite whiff of petrol vapour in the garage now. 

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By floating blockage do you meant the float chamber ? I did set the fuel pressure on the lower side of the range given, and of course the pressure gauge that I have could well not be calibrated correctly especially at the low end of the scale. Maybe tweak it up closer to 2 and a bit psi indicated? 

I agree it is all pretty simple really, however as with the electrics too... everything has to be just so. 
 

I think that I might order some new flexible fuel pipe, because although that I am using was meant to be ethanol proof I do wonder if it is giving rise to odd floaters in the carb. 
 

in the meantime I am also cleaning up an alternative carb that I have been keeping for a just in case day. 😂😂👍 kitchen smells nice 
 

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the dreaded rubber slivers normally end up jammed in the small feed hole in the back of the float needle valve , unlikey to get into the chamber 

many hoses sold were found to ne complete rubbish  stick to branded gates barricade  its sold by club shop and others 

but avoid market place junk its worse than the 50 your old originals 

Pete

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Well you may be into something there. It isn’t an original pump. However for that reason I put an adjustable filter king in line with just a short run of hose to the carb. As original stated I used a pressure gauge to set output to in between 1.5 and 2 psi.

I am going back out to regroup and see if I can find anything amiss. Will take some photos. 

the frustrating thing is that it is almost there! Happy with electrics... the percolation issue can be tackled in time... I will drive again and see if I can glean anymore info. I think the revs were dropping( stuttering) when under acceleration pulling away. 

thanks for continued help 😀😀👍

 

 

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Ok is there some thoughts of why you feel the replacement needs a  regulator   ,yes some are generous in pressure  1.5 to 2.5 is about right 

orig pumps maxed at 2.5    some repro have been found at over 5psi    disaster

you mention the acc pump is giving a good squirt so its not that  are you sure the dizzy advance is up to spec  , try advancing a bit , 

1147 have a high static degrees of advance and at idle of 800 you get 20 deg    

might be worth doing by ear  turn dizzy to get fastest idle then back of a bit  ...check for pinking if it doea back a little till it just stops

Pete

Pete

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Well... I started to get a problem with percolation and also leaking from the paper top gasket ... having changed the fuel pump. At the time I didn’t really equate the two events.

After a refurb, the carb still had a problem. I didnt really have a reliable way of testing the pressure, but a friend said that the super king adjustable filter was a good product and that is what I went with.

Whilst the car wasn’t in my ownership the carb was swapped to a Weber which I think was always running a bit rich and the accelerator mechanism was a bit of a botch... hence my interest to return it to ‘standard’. 

I have just done a really good run of 90 miles and it ran well enough... a bit lacking in the acceleration department ... I will have a tinker with the advance when I get home.
Again, I think the dizzy is not original and I have no idea about the curve. I have purchased an old original and intend to send to distributor doctor when enough pennies are put by. 😀😀👍
 

 

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