carbs seeping fuel from main gasket?

[Marko]

has anybody had a problem with PDSIT carbs seeping fuel from the main body gasket? I've tried 2 pairs of cut off valves and 2 different gaskets and still it seeps out, not dripping but the gaskets are obviously wet.. float level seems fine but I haven't tested pressure as I don't have the equipment to do that but it's the same with 2 different pumps.

short of trying different carbs I'm running out of ideas!

Mark.

[broady_6]

i have some spare carbs you are welcome to try. Have you changed the float needles? the new ones have a habbit of not closing properly. so your float height might seem fine but the needles still arnt closing.

[Marko]

I have tried the valves from the rebuild kit but at the moment I have re-fitted the original ball bearing style valves back in but still the same, just ordered a fuel pressure gauge to see what pressure the pump is kicking out. apparently i could have too much pressure causing seepage..

if the needle valves are at fault then I don't know what to do because I'm guessing originals are NLA so have to make do with either used or iffy after-market quality!

Mark.

[FastySlow]

Old carbs can be difficult to seal, maybe it's just leaking from the fuel sloshing about. I scrape a thin layer of gasket sealant on the paper gasket to make it tacky. Personally I'd start saving for some Weber ICT's, like Porsche I'm not a fan of Solex's I've always found them to be thirsty.

[Marko]

no sloshing, the car hasn't moved an inch yet! I want to stay with Solex carbs so got to try and make what I have work..

I've been trying to get the fuel pressure down from 4.5psi to the recommended 2.5ps but not having much luck but have managed to get the pressure down to 3.5psi ish, that's with 4 additional pump gaskets made out of cereal packets! at that rate I would need a lot more to get to 2.5psi Rolling Eyes surely this can't be right?

also had a look at the carbs and the right hand side carb was dripping fuel out the overflow tap, this was because one of the original cut off valves was defective! I fitted the new ones back in with an extra washer for good measures and it stopped. I'm still not happy with the gasket seal on the main bodies and I think I may have to try another pair of carbs Sad but before that I will try and get the psi down to 2.5, maybe I need to use a thicker material?

Mark.

[JSR-69]

If adding packers under the pump reduces the pressure then maybe you have the wrong length pushrod in there? The Beetle ones changed lengths at various years so maybe the Type 3 did as well?

Judi R

[Editor]

I think the fuel pumps for alternator Beetle ones were shorter as there wasn't the clearance from the alternator body. I'm pretty sure the Type 3 and dynamo Beetle ones are the longer (earlier) ones.

[Marko]

I think the fuel pumps for alternator Beetle ones were shorter as there wasn't the clearance from the alternator body. I'm pretty sure the Type 3 and dynamo Beetle ones are the longer (earlier) ones.

I think you are correct Dave, the top of the shaft is supposed to stick out past the plastic base by about 13mm and mine was about that, it's just I have too much pressure and need to tame it a little I think..

Mark.

[Editor]

Decent needle valves should do that. You may be able to get a pressure regulator for carbs, but I doubt a bit too much pressure would make too much difference. Having said that, I've never tested the pressure on mine.

[broady_6]

silly question. why not fit a fuel pressure regulator?

[Marko]

silly question. why not fit a fuel pressure regulator?

it's easier to to just shim the pump up? I don't want to really add anything else in the engine bay.. just bought some hole punches from car boot sale this morning so going to make a few decent gaskets in a bit

[alex d]

I'd say 3.5 psi is fine, seems like your issue is more the needle valves!

[Marko]

right, got my pressure down to 3psi now so quite happy with that, that's with 6 gaskets on plus original! but it still leaks from the main body? I'm stuck with after-market needle valves as it does the same with original Solex ones, in fact one of the original ones was so bad it dripped fuel from the over flow pipe into the engine after engine turned off. I doubt original needle valves are available so will have to make do with what I have..

the other problem could be warped carb tops but I would have to rebuild my spare set of carbs to find out and that means another 2 rebuild kits

the only other thing I can think of is when I flatted the main carb bodies I didn't use a fine enough grade paper and fuel is finding it's way through there, I used 80grit I think, maybe in hindsight I should have used 320 or 400 grit paper.

[purplepeter]

Have You definitely got the curvy clips that Dave mentioned somewhere recently.. they go in the recess that the float pivot sits in
Are you saying you sanded the face where the gasket sits between the top & bottom of carb?
You could possibly try oiling the gasket before fitting? I'd hylomar it, but that does occasionally come back to bite you in fuel situations!

Curvy clip is item 36 here http://www.hallvw.clara.co.uk/type3/T3pbo/T3pb1-46d.htm

[Marko]

yes I have those "curvy clips", to be honest I'm fed up with it, just been out trying to fine tune it and it back fires and pops and is very difficult to start when hot. I'm going round in circles here and getting no where.. I don't know any cooled specialists in my area other wise I'd book it in and pay to have it sorted.

apart from that it seems to drive OK and stops and steers fine, just gutless and back firing, a bit embarrassing really on it's 1st drive around the block!

a disheartened Mark

[broady_6]

I had problems with hot starts and high fuel pressure. it was on a rolling road at a specialist and he commented on the fast that fitting a regulator would cure this and it did sort it out straight away.

Have you thought about speaking with danny a reichspeed. West stockwith isnt to far from doncaster.

http://www.reichspeed.com/main.htm

[FastySlow]

I thought the recommended psi was 3.5 anyway? Any carb should handle that.

[broady_6]

appreciate you wont be finding it that interesting any more, but im very interested in this and I do let my mind wander across it from time to time. I still none the wiser, other than as you say the sand paper was to coarse. maybe try working up to a 400.

i take it when the engine is running, its running ok other than the fuel over flow? Or does it run badly? have you had it on an exhaust gas analyzer?

[Marko]

I think I found the culprit why it was backfiring and running bad, I swapped the condenser out and immediately it ran better (not yet drove it to be fair) and that could of been the reason my multimeter couldn't read RPM too. not had chance since the weekend to try anything else.

someone over on the Samba forums said that the weeping fuel is almost definitely down to using 80 grit to flat the surfaces so that's another job I can try and fix for good.

I don't have a gas analyser, I have a colour tune kit but could be a pain to try on a Type 3!

[Editor]

When it's back in use, you can tell a lot by the exhaust pipe or colour - whitish deposit on bumper is running a bit lean. Too much black (on plugs too) is rich. Reading spark plugs is supposed to tell you a lot. Give it a good drive then turn off from highish rpm. When cool, look inside the cylinder head (ie take out a plug and look at the colour of the electrodes. There will probably be a bit of soot at the edges, but a nice straw colour of electrodes confirms it's about right.

You can get extensions for the colourtune for flat-fours. I've never had a colourtune - don't know how well it works with an extension.

I'm sure there would be a friendly garage who would do an emissions test for not too much. I went to Halfords to compare the read out on my Gunson's CO gauge - they gave me a value which confirmed the device within the 0.5% claimed.

[broady_6]

if you really wanted you are more than welcome to borrow my gunson CO tester

[Marko]

it's sounding a lot healthier now, just need to balance carbs and sort the weeping but I now know what I have to do to fix that!

I played with timing a bit this evening and a little baffled, according to the notes posted in another thread my distributor should be timed at 0 degrees with both vacuum hoses connected but if I do that then I have a lot of advance at high revs (like 40 degrees!), if I set total advance to 30 degrees to be on the safe side them the idle reading is out.. not sure what to do for best? if I set the timing at idle then it revs nicely but doesn't sound that great if set for 30 degrees total advance. I wonder if my distributor is not in good health..

[broady_6]

I havent read the other thread but did you get the retard side of the vac can sorted out? If thats still faulty it could be a part of the problem letting it over advance.

[Marko]

I fitted a new can BUT it's off an FI distributor so maybe a little out.. but the engine hasn't ran better since fitting it! I'm going to have to except that It'll never be perfect as original parts are hard to find even used.. if someone had a NOS distributor and can to suit my engine it would be a miracle!!

Mark.

[broady_6]

Well its not just the engine it has to suit, its the mass of the car the gearbox and so on. what code engine are you? Presume your just a stock 1600 tp twin carb. Forgive my memory I've spent the last 4 months learning fuel injections systems so I haven't followed the carb forums to closely. Does it have to be NOS? Or would you settle for one that suits the engine to make it run properly while you search for a NOS one?