Carb for single cylinder engine

I've not tried it on a float but I use clear fuel proof lacquer on the hit & miss engines, a few coats sprayed onto the float may do the job. I left the float out of the engine I'm doing at the moment as I tend to just test run them the float chamber can be filled from a dispensing bottle and act as a small tank.

Hi , I wouldn't be able to get fuel proof lacquer here in Northern ireland - they won't even send enamel paint. I have gone the epoxy route and have only quite thick stuff but it seems to be ok. I epoxied a small diameter aluminium tube through the centre. Seems to float alright if you don't get too much epoxy on. I wondered if anyone had ever made a brass float?

I made a tinplate float 26mm diameter and 30mm long many years ago. The material was the thinnest plate that the local model/hobby shop had, maybe 0.2mm. The ends were spun in the lathe and the body was rolled around a former. It was soldered up with the minimum possible solder to keep the weight down. The finished item weighs 6.5g and floats reasonably in alkylate fuel (I think the density is similar to pump petrol).

It never worked due to my inability to make a suitable valve at the time. I decided to use an overflow system for my model SU type carb as this would have needed an even smaller float and valve.

Hi Roger, I was thinking of an overflow system but I couldn't think how to make a petrol pump. How did you accomplish that please? I've re-arranged my tank for the Rumely so it's above the float chamber now. I was reading ETW's article about carbs in a 1946 ME, in that he says the jet should be very near the throttle valve. However the 1831 carb has the jet miles away from the throttle - strange? I haven't got the next article in ETW's series on Carburation without complication though.

Just out of interest my Indian had a cork float with the brass hinge fittings glued in with strengtheners that looked like brass panel pins glued in as well, but as time passed flooding was getting a problem so I sourced a new,new one from the states which is 3d machined in some sort of fuel proof closed cell foam, still with the fittings glued in and has not been a problem for over 12 years. Perhaps this material might be a possibility.

The fuel pump started out as a piece of 20mm square aluminium. I have also built a larger 25mm version but the delivery was too much for this engine. The diaphragm is cut from 1mm Viton sheet using the clamping ring as a punch guide. I decided to use a ball and socket at the rocker end of the pull rod so it would stop pumping against a closed outlet (needed for another application). It is driven by an eccentric mounted on the camshaft drive gear. The inlet and outlet are gravity ball valves with 3mm stainless steel balls. Tiny cross shaped pieces limit the movement to 0.5mm.

Thanks Roger, that looks like really nice work. Meanwhile my epoxied cork float seems to be ok. I was looking up fuel resistant foam online but kind find any. Cork is free and if it works I'll stick to that.