Morris Minor Owners Club

Hi,

So to solve the overheating problem I fitted a HS2 SU carb and air filter. The carb was second hand, so I cleaned it, fitted a new jet and float. Now tha car won't start.

It turns over but only bursts into life if fuel is dribbled down the carb. The fuel pump is fine, there is no blockage in the fuel line to the carb and I have cleaned the plugs, which are new. Should I replace the needle or might the problem be the jet assembly?

I was really hoping to get Morris running again, such a shame, so close...

Why would you think the carburettor would cause overheating?
I would probably look at the main jet next in answer to your question but was there anything wrong with the original carb in the first place?

I changed the carb as the car has a replacement 1098 engine but had the original carb and air filter which needed to be changed. Under load, not enough air was being drawn into the engine and this built up oil pressure and subsequently jetted out and overheated.

Could you tell me what the 'main jet' is please?

The main jet is the bit that moves up and down underneath the carb when you operate the choke and has a flexible hose to the bottom of the float chamber. Do you have a workshop manual or parts list to help you identify things?

Sure, I replaced it with a new one. Is there some adjusting that may be needed?

Was the union into the bottom of the float chamber assembled properly? Did you dig out all the old sealing material? If the rubber seal is not fitted properly then it can block the end of the hose.

Thank you, I will check that today.

before you do anything else take the top off the float chamber on top of the cab (Two screws)r and see if there is any petrol in there,sounds like a stuck needle valve not letting petrol into the carb

Thanks for this.

There is fuel in the float chamber and the car can be started by putting my hand over the air inlet and plenty of fuel gets sucked into the engine. The engine then goes straight to high revs and seems to build up pressure in the crankcase and jets out oil underneath.

I seem to be either...

A: Going round in circles
B: Making progress or..
C: Trying to fix something that is badly broken.

Fearing the last option, I have said I will tow it round to a Minor specialist who also has engines available should the worst become inevitable. Thank you evryone on this forum for your support.

Can anyone help when refitting the main jet flexible pipe to the bottom of the float bowl with new o ring ( see item 4 part C in picture) do you put the o ring into to hole on the float chamber or push it over the pipe next to washer please, tried both and the pipe seams to move around a bit , do not want a leak

I've always pushed it well onto the hose, then insert the assembled bits into the float chamber. With the hose fully seated, slide the seal/washer/nut assembly into the hole and tighten the nut whilst keeping the hose pushed right in. A bit fiddly as the "spring" sheath makes it difficult to hold the hose, but it does work.