Morris Minor Owners Club

Hello all,

I own a 1969 Morris Minor Replica Convertible, which I bought from Charles Ware in 2009. During the 8,000 or so miles I have since travelled with her the only problems were a leaking brake slave cylinder and a failed fuel pump. Last year she took the 1,125 miles to the Morris Centenary and back without any problems. But today I had the same situation for the third consecutive time when I wanted to take her out on the road:

The engine starts on the button, and after getting her out of the garage I can push the choke in about halfway. When I have left the estate where I live and get on the open road I can push the choke in completely. The car runs very well for about 5 to 10 miles. When accelerating from a stop at a crossroads or so the engine suddenly runs on three cylinders only and loses power. If I stop, the engine is idling perfectly on all four cylinders, but accelerating in neutral means I lose one cylinder. Pulling the choke again does not change anything. After a few minutes of idling the engine is running as usual, and I can carry on.

Today I had no immediate place to stop, so I was limping on three cylinders for about half a mile when the engine died. I had a look under the bonnet, couldn't find anything that looked unusual, so I tried to start the engine again. At the third attempt (without choke or throttle) the engine started running as if nothing had happened. I drove for a further 45 miles without any problems.

The car was last serviced in April 2013, the electronic ignition checked and the carburettor tuned with a slightly richer mixture than applicable, as we found out that this gives a smoother running.

I have a suspicion that the fault lies in the area of the carburettor, possible the choke.

Does anyone have an idea what is the reason for the misbehaviour of my engine and what can be done?

Thank you for all your answers.

Cheers
Hubert

Fuel pump? In the carb - is the piston free to rise and fall - with a nice clunk (damper removed) - and is there a little bit of oil in the damper? Since you have electronic ignition - hopefully it is ok, since usually 'all or nothing' - but it could be the rotor arm breaking down , or tracking in the dizzy cap - or bad HT leads. But the 'complete engine stop' would encourage me to check the fuel pump first of all. Clean the points - and then get it to pump a full gallon into a can - does it manage that without stopping?

Hello bmcecosse,

I would exclude the fuel pump from the list of possible faults. I fitted a brandnew one in autumn 2012, and I have done only 2,000 miles since.

The piston in the carb is more likely the cause, I think. I will check that. There should be enough oil in the damper, it was refilled about 100 miles before the problem first occured. Could it be that the carburettor is drawing too much air through a blown gasket? The problems always started after I had slowed down by shifting back to 3rd and 2nd gear.

I will also check the distributor, you never know.

Thank you for your reply.

Cheers
Hubert

[quote][/quote]I would exclude the fuel pump from the list of possible faults. I fitted a brandnew one in autumn 2012, and I have done only 2,000 miles since
Dosent mean that its still ok,it would be my first to check.

Yes - don't exclude the pump without a test. There may have been dirt in the tank - now drawn through and blocking the filter.

I think one of your HT leads may be earthing when you accelerate for some reason. Check they're not too near the metal at any point or if possible try the car with a different set.

sounds like fuel starvation take the filter out of the fuel pump and cheak its clean is the float valve in the carb sticking ive had that too .

In the meantime I have dismantled the carburettor, expecting dirt in it, but it was all clean. I borrowed an endoscope and had a look into the tank, but there was nothing in it except the petrol. The visible parts of the electronic ignition looked ok, so in the end I decided to take the car to a garage, specialized on vintage British cars.

I don't know why I hadn't checked that, but the first thing they did was to unscrew the spark plugs. The first two looked ok, but the rear two were white, which means these two cylinders had a combustion which was too hot. After examination they also found the reason for this: The manifold had bent, possibly because a screw hadn't been tightened enough. This has left a gap which allowed air in and led to a weak mixture on these two cylinders.

It now sound logical, too, that the engine always ran perfectly after some time. When the metal got hot, it expanded and closed the gap again.

They have dismantled the mainfold, had it grinded flat and fitted it with a new gasket. Now the engine runs better than ever.

When the problems began, I had a suspicion that there was air in the system where it should not be let in, but I would have never expected it in that place.

Maybe this can help other Moggy owners if a similar problem occurs.

Cheers
Hubert

Crikey! Well done that garage. Yes - the plugs were the give away.