Morris Minor Owners Club

I was enjoying a spin in my Morris Minor today when I started having some stalling trouble. I had just filled up with a fresh tank of petrol and had dropped off my brother to collect his car from the pub. There was quite a strong smell of petrol inside though didn't spill any and didn't see any leaking when I checked later. When turning off the main road to the pub car park I stalled, simply because I did not have the revs high enough. When I was trying to leave the pub the engine stalled again and I had a lot of trouble starting the car again. When I did get the engine started it was incredibly sensitive and stalled simply from trying to build the revs too quickly while in neutral. The oil pressure was also slow to build and was a bit low when it did. When the key was half turned there was a strange random clicking noise coming from the dash, the red ignition light also flicked on and off when I did get the engine to a dodgy state of idle. Eventually I got away after a few more stalls and hill starts. The engine only started from me leaving the car completely off for 10 mins or so. I then started it and let it run idel for another 10 min or so. The radiator was not that hot to the touch and everything seemed normal under the bonnet. As I was motoring away the engine started to feel gradually less sensitive though I could feel an increasing amount of heat coming through the interior heater even though it was turned off, this could be normal perhaps? The car had started fine that morning when I left despite not being used for a couple of months and later that day I was able to move the car around the drive no problem. I checked the oil and it was clean and at the right level.

I can't work out what I had done wrong or what might have caused it. Flooded the engine with choke maybe?- I cannot remember using it much though. What do these symptoms sound like to you guys?

Merry Christmas and thanks,

Edward

Welcome to the forum! It does sound a bit like excessive choke - you should only need that for a cold start - and then only for a few seconds, slowly easing it back in. Hot start should be done without choke. Otherwise - it could be sticking needle valve in the carb - causing flooding. Are you aware of the fuel pump ticking away 19 to the dozen at any time ??

The clue here is a fresh tank of gas. If you've got muck lurking in the bottom of your tank (and considering the age of moggies most do) a fresh tank can stir it up, particularly if it was near empty when you filled it. What often happens is that flakes of crud work there way through the fuel line and either clog the filters or clog passages in the carb. In addition to what bmcecosse mentioned, it could be a sticking float bowl valve. A speck of dirt could do this and -- depending on where it lodged -- cause either flooding or fuel starvation. It sounds like it may have fixed itself, and this sometimes happens when the muck finally lets go and gets pulled all way through. However -- always -- beware of spontaneous remissions! You may also have water in the tank, which at rest will settle out on the bottom. I think I'd check the fuel filter screens (one in the original Lucas pump if that's what you've got, and one in the carb). Also, obviously, if you've added an inline filter check that too. If your filters are full of crud or show any signs of water it's time to have a good look at the tank (and perhaps flush it). A tip: If at all possible, don't let the tank drop down below half full for a bit and see if the problem stays away.

If you get stuck and you're so inclined, here's something to try: Remove the air filter, exposing the throat of the carb. If the car will run at all, get it started and idling. Now -- at the carb -- rev it up some and then slap your (other) hand over the mouth of the carb to seal off the air intake. The car will stall if you leave your hand there. What this does is significantly increase the vacuum in the fuel circuit of the carb temporarily and will often pull any crud through the fuel circuit.

Hello again everyone, and thank you for all your responses.

The stalling is back! I fitted a transparent inline filter just after the fuel pump since our last discussion which had collected some crud (not much) and I was optimistic enough to assume the problem was resolved. However I filled up with fuel again (almost empty tank ) and the engine was immediately very sensitive and stalled if I built the revs even fractionally while in neutral. More embarrassing pushing of the car at junctions and my girlfriend and brother assuring me they will never get in the car again.

On inspection the inline filter was empty of fuel. The fuel pump was trying to pump but it seemed to be working against a vacuum and was only able to draw a very small trickle that was not nearly enough to supply the engine.

What confused me is when I removed the float chamber and released the valve the fuel ran freely albeit with air bubbles that filled the inline filter with about 50/50 fuel and air. I had a look in the aluminium carb bowel and that was about 50/50 air and fuel too. When I lifted the float valve up high I expected the air to flow out and the inline to fill with fuel but it seemed to defy physics and simply remained mixed with air and fuel. Bubbles trickling up from the pump.

When I connected everything back together the engine started first time and was back to normal???

Admittedly I ran out of weekend to take the fuel tank out and have a good poke around at that end which I assume is the next step. Any clues of what to look for?

Thanks again,

Edward

My initial thoughts are, there must be something causing the fuel to only come through in small amounts. If the pump is clicking, I think it's safe to assume it's working ok, although lets not ignore it. When the engine is cold, have you disconnected the outlet pipe from the pump, got a friend to hold a big jar over the pump exit and turn the ignition on? If so did plenty of fuel come through. There should be loads, do not do this on your own.

If small amounts:

1) There's crud blocking your pipe from the tank.
2) Your fuel cap isn't venting to give the fuel gravity to get pumped through.
3) fuel pump faulty.

If large amounts, you need to clean out the carb and give it a clean, these are some notes I made, when doing mine.

Tuning the Carb

· Warm up the engine.
· Turn off the engine.
· Mark the pot at the base to ensure you put it back exactly the same on re-assembly.
· Using some engine oil, remove any carbon deposits from inside the pot and dash pot. Check for any marks, scratches or burrs, if there are some lightly emory them down smooth.
· Smear a thin bit of oil from your finger over the grooves in the dash pot.
· Assemble the pot over the dash pot out of the car, and ensure the dash pot falls smoothly into the pot. Make sure it falls the full length under it’s own weight smoothly all the way home.
· Make sure the brass jet and jet sleeve at the base of the pot is flush with the aluminium casing.
· Fit the carb back together remembering to fit the spring and to fill the dash pot with oil.
· Check the cap of the plunger has a clear and visible breathing hole.
· There is a small spring under the pot between the jet and the carb. Make sure this is free, it returns easily and makes a noise as it lifts the plunger.
· Start engine.
· Speed the engine up a touch by twisting the screw with a screw driver.
· Pop around to the exhaust and listen for “fluffyness”.
· The fluffyness needs to be smoothed out.
· Using the graph above you need to find the point at which the engine runs the quickest by twisting the nut at the base of the carb.
· You need to rev the engine to clear it every time you adjust the nut.
· Listen at the exhaust to hear the engine rhythm.
· You may need to play with the settings until all the fluffyness is removed.Ony turn the nut one flat at a time.
· Slow the engine down
· Press the small spring and the engine should almost stall.[frame][/frame]

Sorry the graph is naff, basically you need to remove the brum brum bru brum bru brum sound at the exhaust and tune it to a long brrrrrrrrrrrrrrrrrrrrrrruuuuuuuuuuuuuuuuuuuuuummmmmmmmmmmmmmmmmm.

While you are under the bonnet make sure there is still a points gap, a very small one will also give these symptoms.

Ive just fixed my friends dub, and the problem was the briaded rubber hoses had perished and the pump couldn't draw the fuel through consitantly because the walls of the short peices joining the copper sections were leaking air in, but not fuel out
nice easy fix for a change n cost about a £1

lowride stepside wrote:Ive just fixed my friends dub, and the problem was the briaded rubber hoses had perished and the pump couldn't draw the fuel through consitantly because the walls of the short peices joining the copper sections were leaking air in, but not fuel out
nice easy fix for a change n cost about a £1

That would explain the smell inside this fella's car if the fuel line was perished. Otherwise is there a vacuum in the tank because it sounds like it...

More likely -blocked fuel filter. Clean the one in the fuel pump - and throw the extra one away.........