Morris Minor Owners Club

For some time now I've had an intermittent running problem where once the car has warmed up, it starts kangarooing and full power isn't available. Feels like fuel starvation, yet some days it would happen and others the car ran fine. Fuel pump and condensor were swapped to no avail, so my attention yesterday turned to the carb.

There have never been any starting problems, hot or cold, in the past.

The carburretor has had a hard life and the mixture couldn't be adjusted as the nut just went round and round without going up or down. As the plugs were a healthy colour and fuel consumption was around 30 mpg I left it. The other thing which raised my suspicions about the carb being at fault is that I suspected the needle to be ever slightly off-centre, and the suction disc could occasionally take its time to come down.

So yesterday I decided enough was enough and went tinkering, with the car running I undid the two screws holding the bellhousing to the carb body and lifted it up slightly, rotating it 180 deg. to see if this had any effect. Of course the running of the car changed as I lifted the bellhousing, but I didn't ever allow the suction disc to come out. Soon the engine stopped, and try what I might I haven't been able to get it to fire since.

I have since taken the bellhousing off completely, cleaned everything, put fresh oil the dashpot, checked the piston action etc but still it won't fire.

The float bowl is full and fuel pump is ticking away. Plugs are getting wet with petrol. Air is also being sucked in.

Compression readings are around 100 psi on 2 and 3 with 1 and 4 being somewhat lower.

To add to my woes there now isn't any spark at the plugs when earthed against the engine. I have changed them and still nothing doing, yet the c.b. points are sparking. Also swapped dist. cap and leads.

Most grateful for ANY suggestions before I set fire to the car. (Well I would if it wasn't stuck in the damn garage!)

It's never the coil. -really????-

Well, I have no reason to doubt the coil as the engine ran before I started messing with the carb.

Only other thing worthy of note, re there being no spark at the plugs when earthed, is I removed the rotor arm and held it roughly central in the dist. cap, and it didn't seem to quite reach the terminals. The cap does have a fair degree of wear, but in any case I swapped it for another used one, and the car was, as I said, running before, which gave me no reason to doubt the ignition.

I'm thinking perhaps the mixture is too weak.

I know you can't adjust the mixture with the nut, but is there anyway you could richer it?

the suction disc could occasionally take its time to come down

Refer to the manual and sort this out first.
If it's been like it for a while the needle and jet are probably worn and need replacing for a quality job.

Aye Marky, a replacement has been on my mind for some time.

If anything it was running slightly rich, Dean, as it never needed much choke and the fuel consumption wasn't the best.

Still not going anywhere yet whatever I have tried.

No I mean since you messed with the carb. Probably was running rich, but taking the pot off has knocked it out of adjustment.

If the mixture is now too weak, the car isn't going anywhere.

Sure you haven't just 'wet' the plugs? Try another set - but while they are out, spin the engine over to clear any excess fuel. Is the rotor the correct one for the cap? By all means - when you have done all the usual checks - test the coil. Simply hold the king lead a small distance from earth and flick the points - it should spark......

JOWETTJAVELIN wrote:. the mixture couldn't be adjusted as the nut just went round and round without going up or down.

The reason that the mixture nut went round and round is because the jet locking nut above it is loose allowing the jet to turn with the mxture nut

New rotor arm ordered. Mike, I have had the whole jet assembly off, and tightened it back up. In any case it wasn't leaking fuel which would indicate a loose nut.

Will perform a coil test.

I changed the plugs and then dried them with tissue before earthing them.

I'll be damned if this car is going to cause me to miss another National.

Try replacing the "replaced" condensor.

King lead issues a nice fat spark when earthed.

Thank goodness -it's not the coil........phewwwwwwww. So now, you need to find where that spark is going - if it's not getting to the plugs.......

It would seem that either the rotor arm or dist. cap has worn out, yet I can't understand why these would suddenly 'die' as soon as I began tinkering with the carb.

In any case I am getting nowhere apart from flattening the battery each time so will wait until the new parts come.

If you doubt fuel supply - then tip an egg cup of petrol down the carb - and crank it...... If it runs for a few seconds - then indeed fuel supply was the problem.

I don't doubt fuel supply as the float bowl is full, and when slackened the banjo union pours it out.

The fact that there isn't even a hint of firing suggests an ignition fault, as I am frankly stumped that lifting the carb bellhousing up slightly with the engine running would cause it to grind to a halt and never start again.

It's teaching you to leave things well alone......

I'll take it to the nearest Morris Dealer next time.

A new rotor arm has got the car going again.

Ordered from Simon BBC, Powermax red rotor arm. £4.50 incl. postage, arrived next day.

However, the kangarooing is still present so a recon carb is needed.