Righto - I'm going to make myself clear right now: I hate Carbies

OK, now that I have that out of the way , I have a 28 PICT carbie on my '63 Bug. For the week leading up to our trip to Warwick I had been experiencing problems with a strong fuel smell in and around the car once the engine was turned off and more-often-than-not the engine would run on when it was switched off. The engine was also hard to start when it was warm, usually starting on one, then two, then three cylinders....

I checked the entire car for signs of fuel leaks and the only place that looked suspicious was the carbie (it looked damp around and below the throttle shaft) - so it looked like it was flooding...right?

I removed the needle and seat and checked their operation (it was a fairly new unit) and it appeared OK. The float also appeared OK.... Hmmm.

I had had it suggected to me that I should put a second seal/washer between the top of the carb and the needle and seat in order to space it down - and therefore cut the fuel off earlier, so I did this on the Friday before leaving for Warwick but didn't have a chance to properly test it.

The car ran great during the trip, but every time I switched the engine off the smell of fuel was still obvious and I had to crank it for ages to get it to start (if I restarted it when it was hot).

Today I opened up the carbie again and replaced the needle and seat with another one from one of my dozen 28PICT's that are stashed away in my shed, then I went for a drive....

The smell of fuel is still there, although not as strong, and the car is still hard to start whilst it is warm.

Now what do I do? Replace the needle and seat with another one and cross my fingers? Replace the float again? Hit the carbie with a BIG hammer?:bounce

I really don't have a lot of knowledge about carbies, so any suggestions will be greatfully accepted.

Cheers,

R

it does sound like symptoms of a worn or sticky needle and seat
also check that ur float is still ok, might have a worn spot up high which can cause intermittent probs like this
i had one like it drove me nutsl i'd swapped everything in the arb bar the float
does it still have an original fuel pump?
i cant remember if 40hp have the fuel cut off valves in the top been to long since i clapped eyes on one

-Joel

you have the answer-----------------------kalmaker-------------get to it

Replace your float itself rat-attack. Im wondering iffen its sinking and not controlling fuel pressure adequately any more.
Another angle might be that the carb top cover could be cracked or perhaps porous where the fuel line screws in and is allowing fuel to get past and into the bowl and flooding the engine.
The fuel pump will retain a surprising amount of fuel under delivery pressure and it is bleeding into the engine flooding.

Try just changing the carb top along with the float with another from your collection.
L8tr
E

I had a similar problem with a carby on a commodore. The float had become porous and soaked up some fuel. Only was a few grams heavier but resulted in flooding.

I went to a brand new 30 pict-1 carb on my 1200 splitty kombi and solved all problems. Good carb, easily adjusted and tuned and very reliable. Also slightly more power with the bigger throat and they have their own throttle return spring attached to the carby, much better than the set up on the 28pict.

Ross.

go with the 30pict 1. The 28 has given me many headaches over the years. Ive changed needle and seats, whole tops, jets and when they are over thats all there is to it! A new 30pict1 and off you go.

Hi Folks,

Just a quick update - so you didn't think that I had just given up!

I haven't had much time to 'play' with the car recently due to other commitments however I did spend some time on it last Friday and this is what happened:

Firstly, I made a trip down to my local VW workshop and picked up another, complete and rather slimy 28 PICT-1. I made a point of picking up a rather oily example as I figure that if it is coated in oil, then it couldn't be leaking fuel, otherwise it would have washed it clean (OK, perhaps not the best argument, but it worked for me ). I also managed to find a 6 volt fuel cut-off solenoid that still worked, so that came home with me too!

I then returned home and dismantled my new posession, checking for problems along the way, then I cleaned everything very carefully. Once it looked reasonable I re-assembled the new carbie, using all the parts that it origionally came with (ie: not using any of the parts from other 'leaking' carbies). The only minor change that I made was to fit the fuel cut-off solenoid in place of the fixed idle jet.

I then removed the old 28 PICT from the engine of my '63 Bug and replaced it with then new, freshly cleaned 28 PICT-1. I wired up the cut-off solenoid and took a rough stab as to where the choke should be set, then having double checked the everything was tight and properly connected, I started the engine.

I allowed the engine to warm-up (and re-adjusted the choke which was no-where near where it should have been!) and gave it a quick tune before going for an extended 'blat' around the block.

When I returned home, I came to a stop in the driveway, jumped out and adjusted the idle speed up slightly then switched the car off - and for the first time in a long time the engine just stopped - no running on! This was promising....

I wandered inside to grab a drink and upon my return I was greeted by the smell of petrol - sure enough it was leaking out of the carbie, through the throttle shaft hole :cussing

I then decided to try re-adjusting the float level again (as I had done with the last carbie), but after a quick run around the block again it was obvious that this was not going to cure the problem as it still leaked once the engine was turned off...

Totally confused, I decided to turn my attention elsewhere, and I chose to add extra spacer gaskets under the fuel pump to reduce the pump stroke (and therefore the pump pressure) - as I had a number of fuel pump gaskets in my 'misc gasket and seals' box, and I was becoming frustrated I decided to add 3 gaskets at once and see what effect it had on the engine .... none what-so-ever - I could still easily reach the speed limit on the freeway (110km/h), and when the engine was switched off the carbie still leaked fuel.

At this point I gave up - I drove the car on a club run on Sunday and it actually feels a little more responsive with this carbie on it (I noticed this during the first test run on Friday), but the carbie still leaks fuel when the engine is switched off.

It has been suggested that I replace the fuel pump in case the pressure relief valve that is supposed to be in the pumps has stopped operating for some reason - I suppose that I should give this a go as I have no idea what else to do.

What do you reckon? As much as I would like to upgrade to a 30PICT-1, if this problem is being caused by something other than the carbie then all I will be is back at the starting point with a new leaking carbie - I'm sure that the cars weren't sold new with this problem so there must be a cure for it.....


Aaaaaaarrrrrrrgh! :bounce

R

you not parked on a hill are you?
fuel pump rod length incorrect for your "new" pump?

[ Edited on 22-1-07 by jnr356 ]

Start at the front of your car and check all the fuel lines to see if they are weeping or leaking fuel usually weaps and runs down insidet he tunnell so you get the smell ( I had this on the 76 )

other than that i would chuck the Brazilian fuel pump out and try n find a good genuine unit and replace

the extra washer under the needle n seat lowers the fuel level in the carbie bowl and reduces the chance of the fuel venting out the vent tube in the bowl

try the fuel pump

Is the fuel leaking on the outside of the carbie can you see it ??? or just smell

I have changed 3 - 4 old 28 pic carbs before before finding a good one. Many of them do exactly what you are describing and leads to you trying all sorts of things to rectify the problem.
30 pic1 is the way to go, and a lot easier to find a good one, even if not buying new.
Sometimes it really is easier to buy new and save the headache though.