Zenith 26va Carb. Float - sunk!

[DaveT]

Well I nearly had a fire yesterday when the float in my 26va carb decided to sink so allowing the pump to work overtime and push petrol out of every orifice on the carb.

When I took the float out you could hear the petrol sloshing inside so I weighed it at 30 gms whereas an empty float is 13 gms.

Question is where can I get a new float from as they don't seem to be listed in the spares lists of the usual suppliers. 

Also how would I go about finding the leak and repairing it as for obvious reasons I don't want to apply any heat to the solder on the bottom and I can not see any bubbles when it's sunk in a jug of water. 

The petrol also managed to remove the majority of the paint off the plate above the exhaust, better than nitromors. 

Any suggestions gratefully received.

Dave

[JonE]

Have you seen whether a stayup float from Burlen fits? - give em a ring. They are v.expensive - 28 quid or so, but on overhauling an SU it was suggested to me by another forum user and I thought it, with modern fuel, would be fit and forget.
http://stayupfloats.co.uk

[Robert Leigh]

Well I nearly had a fire yesterday when the float in my 26va carb decided to sink so allowing the pump to work overtime and push petrol out of every orifice on the carb.

When I took the float out you could hear the petrol sloshing inside so I weighed it at 30 gms whereas an empty float is 13 gms.

Question is where can I get a new float from as they don't seem to be listed in the spares lists of the usual suppliers. 

Also how would I go about finding the leak and repairing it as for obvious reasons I don't want to apply any heat to the solder on the bottom and I can not see any bubbles when it's sunk in a jug of water. 

The petrol also managed to remove the majority of the paint off the plate above the exhaust, better than nitromors. 

Any suggestions gratefully received.

Dave

I have heard that modern petrol attacks some solders, so possibly this is the reason for your problem. I suggest that you work in the open air and heat the float with a hair dryer or fan heater. When petrol appears turn the float so that the leak is at the bottom, and keep it that way until drips stop. You are best to let it cool after that then repeat the process until you don't get any more drips. At that stage the float will contain air and petrol vapour, so I suggest repeating the process of cooling and heating a few times which will reduce the proportion of petrol vapour. Then you can practice your soldering skills at the leak point. With soldering cleanliness is next to godliness, and keep the amount of solder to a minimum or you will exceed the 13 gm target weight. Good luck! If you are still in trouble I will sell you another float, but I can't guarantee its life!
Robert Leigh

[Mike Costigan]

I had a punctured float on another car; with the float out and standing on a paper towel the source of the leak soon became apparent; vigorous shaking got most of the petrol out, and then dropped it into a saucepan of hot water. The ensuing trail of bubbles confirmed the leak(s) - multiple in my case, the whole side of the float had stress cracks - and a thin skim of solder has sealed it (so far!).

[Chris KC]

Well I nearly had a fire yesterday when the float in my 26va carb decided to sink so allowing the pump to work overtime and push petrol out of every orifice on the carb.

When I took the float out you could hear the petrol sloshing inside so I weighed it at 30 gms whereas an empty float is 13 gms.

Question is where can I get a new float from as they don't seem to be listed in the spares lists of the usual suppliers. 

Also how would I go about finding the leak and repairing it as for obvious reasons I don't want to apply any heat to the solder on the bottom and I can not see any bubbles when it's sunk in a jug of water. 

The petrol also managed to remove the majority of the paint off the plate above the exhaust, better than nitromors. 

Any suggestions gratefully received.

Dave

I have heard that modern petrol attacks some solders, so possibly this is the reason for your problem. I suggest that you work in the open air and heat the float with a hair dryer or fan heater. When petrol appears turn the float so that the leak is at the bottom, and keep it that way until drips stop. You are best to let it cool after that then repeat the process until you don't get any more drips. At that stage the float will contain air and petrol vapour, so I suggest repeating the process of cooling and heating a few times which will reduce the proportion of petrol vapour. Then you can practice your soldering skills at the leak point. With soldering cleanliness is next to godliness, and keep the amount of solder to a minimum or you will exceed the 13 gm target weight. Good luck! If you are still in trouble I will sell you another float, but I can't guarantee its life!
Robert Leigh

Sounds good to me. I'd have thought you could get another carb for £28!

[bob46320]

I fitted a "splash plate" onto my exhaust, so if petrol leaks out of the carb, it hits the splash plate and evaporates/ drips off away from the exhaust pipe. Its simple enough, 2 big Terry Clips pop riveted to a bit of aluminium the size of a postcard . The best plate is stuff from an old fridge as its surface is all "wrinkly", a bit like me.

[Colin Wilks]

Carburettor Hospital quoted me for a float for a Zenith 30 VEI, so may have stock.
http://www.carburettorspecialists.com/
0345 061 4477
chipmork@btconnect.com
When I was in contact with him in early November he was about to close for three months, so should be back in action in Feb.

[Steve Jones]

I did exactly this before Christmas to three floats and took them apart at the same time to repair dents. The float is sealed to the bottom with a blob of solder. With a 2mm drill bit, drill this out. There's already a hole behind the solder. With a bit of shaking, you can then drain the contents. Boil in a kettle and then let it stand for 24 hours and then carefully melt the solder around the seam using a small gas soldering torch. It requires minimal heat for it to separate. Once split, you can clean the two halves and press out any dents.

To re-assemble, hold each half in turn in aluminium soft jaws in the vice (gently!), heat around the solder to the rim and wipe excess away. Once done, you'll find that the two halves can be fitted back together and then, again, holding the float gently in the soft jaws, heat the seam and run new solder into the joint. You can do about a third of the circumference at one go, turning the float to get to the next third. Finally, a blob of solder into the hole in the bottom and job done.

I should say that I don't have any cars that use Zenith carbs these days but I did have some duff floats. My aim was to respond to a challenge from Charles Ping who said he didn't think it was easy to do

Steve

[DaveT]

I did exactly this before Christmas to three floats and took them apart at the same time to repair dents. The float is sealed to the bottom with a blob of solder. With a 2mm drill bit, drill this out. There's already a hole behind the solder. With a bit of shaking, you can then drain the contents. Boil in a kettle and then let it stand for 24 hours and then carefully melt the solder around the seam using a small gas soldering torch. It requires minimal heat for it to separate. Once split, you can clean the two halves and press out any dents.

To re-assemble, hold each half in turn in aluminium soft jaws in the vice (gently!), heat around the solder to the rim and wipe excess away. Once done, you'll find that the two halves can be fitted back together and then, again, holding the float gently in the soft jaws, heat the seam and run new solder into the joint. You can do about a third of the circumference at one go, turning the float to get to the next third. Finally, a blob of solder into the hole in the bottom and job done.

I should say that I don't have any cars that use Zenith carbs these days but I did have some duff floats. My aim was to respond to a challenge from Charles Ping who said he didn't think it was easy to do

Steve

I've just had a shake of the float over some blue paper and yep. it's leaking from the bottom solder and from the solder around the circumference. 

So as this carb. has been fitted to my car for 20+ years I'm going to blame the EU and the Ethanol unleaded petrol.


Now I'll have to smarten up on my soldering