Morris Minor Owners Club

I am a new member and this is my first post on this excellent site! Have just got fully restored Minor 1000 , new engine 1098, box , brakes etc, carb refurbished, First 200 miles on new engine, when i brake hard to avoid danger , when accelerating away it sometimes dies to the point of stalling or actually stalls. Have put 3 in 1 in piston damper to thin it out but has not worked, i will take the car back to the garage but cannot do it yet ! Anyone got any suggestions as to what's wrong ?

Welcome to the forum. Do you have a servo? It may be faulty. I can only think you may be drawing a lot of vacuum when you brake hard causing you to stall??

Does the carb piston move freely, and drop with an audible clunk onto the jet?

A small amount of adjustment to the fuel mixture would probably cure the problem. It may be running a bit weak and the sudden lift off the accelerator is causing it to stall. Mark one of the flats on the carb mixture nut, the brass nut under the carb, with tippex or similar as a reference point and with the engine fully warmed up, turn the nut down a flat at a time until you get the fastest, smoothest tickover. If there is no improvement turn the nut back to the starting point and try turning in the opposite way.

Thank you for all your comments, i spoke to a guy who new what he was talking about and he suggested a sticking piston might be the cause. How do you get to it and what do you do next? ps apols for my 'newbie' question!

MarkyB already told you that above

Take the airfilter housing off the carb completely and you'll see a vertical cylinder inside the carb, lift that up vertically with your finger and check it falls with a healthy clunk. You say the carbs been rebuilt, its probably not a sticking piston as such as more of a misalignment of the main jet and its fouling on the piston.

I think you need to centre the main jet.

hope this helps a bit

Steve

I have this exact same problem with my Moggy, servo fitted. Logic told me it was something to do with the servo but posts on here seem to verify it. It mainly happens in traffic when I'm jumping between clutch and brake to stop and start - and not so much when slowing down for a junction - but the engine does 'hesitate' just when you stop under heavy braking before catching itself and returning to idle. Is there any adjustment in the servo set up? What should I look for? Thanks in advance.

A servo introduces a 'slug' of air into the manifold - just when it doesn't need it if you want to rev up and move on...... Either throw away the servo (best solution really) - or richen up the mixture slightly. You could use thicker oil in the carb damper - but this will compromise acceleration slightly....... I assume the idling speed isn't set too low ?

No, idle speed was set very low when I first got it - so low that it would barely tick over with a warm engine. I ended up using the hand brake in stop start traffic as the brake so I could feather the throttle to keep the engine turning over. I've since turned the idle speed up a little which has improved things a lot, but it still threatens to stall after heavy braking. I'll have a bit more of a play and read up on actually how servos work which will probably help my understanding