irregular running maestro 1.6S

[kawim]

I am a new proud Maestro owner form Holland.
I just purchased a 1987 Austin Maestro Mayfair 1.6, S-type engine. The car was completely overhauled and sprayed in 1999, and still looks very good. The only problem is that the engine doesn't run properly. The idling is very irregular, I turned up the idling speed up to 1300 rpm to prevent the engine from stopping. Also when driving, especially in low revs, the engine runs irregularly. It looks as if the engine cannot get enough petrol. The car has just passed its MOT. Could it be they set the carburettor too lean???? If so, how to adjust this? Or are there any known faults with this type of engine to cause this problem?
I hope people from the country of origin are able to help me in this respect.

[BikerGran]

I'd say the first thing would be to replace all the vacuum pipes - I had this sort of problem with mine - I checked all the pipes and they appeared ok but I put it into a garage and they replaced the pipes and solved the problem .

WQelcome to the forum, glad to hear you have one of these very nice British cars, please keep us updated with your progress with it!

[G Force]

The car has just passed its MOT. Could it be they set the carburettor too lean???? If so, how to adjust this? Or are there any known faults with this type of engine to cause this problem?


Hi and welcome to the forums.

If the problem has started since the car went in for its MOT test, then the mixture setting on the carb could be set too lean. To adjust this try turning the mixture adjustment screw clockwise in 1/4 turn increments to see if the idle quality improves. The mixture adjusting screw is located just below the fuel inlet pipe.

If you had problems before the MOT the problem could be air leaks in the vacuum pipes or breather hoses. A sticking ORFCO valve if fitted, or plug gaps set too narrow. You can find information on how to check and fix these problems in the Frequent Questions Section under S series tuning.

Gary:)

[PhilD]

I think another possibility would be a faulty plug or HT lead. If you carefully remove each plug lead in turn with the engine idling (using a pair of insulated pliers to prevent electric shock) and you find there is no difference to the engine speed when one lead is removed, this narrows it down to a problem with the HT lead or plug on that cylinder. To isolate which of these elements was the cause assuming the plug gap to be correct, you could then swap the plug on that cylinder and see if the problem remains.

[Terry]

Hi. You should also check the dizzy cap and rotor arm are in good nick. Also make sure there is oil in the dash pot.

[kawim]

Thank you for your quick responses. I hope next weekend I'll find the time to start working on it. I'll start on the vacuum pipes as I've read in this forum many people have problems with these. I bought the car the day after its MOT, and on the MOT paper was written they adjusted the CO, so I guess they adjusted the fuel/air mixture. In the bills I received from the former owner I found several repairs on the carburettor. I just ordered a Haynes repair manual, hope to get it tomorrow. This might help me along.I'll keep you posted on my findings.

[Simon]

It could also be a faulty fuel pump. The rubber diaphragm splits allowing fuel and oil to mix (causing the sparking plugs to foul up) and also results in poor fuel delivery to the carburettor.

[kawim]

Yesterday I changed the sparkplugs. After that it refused to start completely. Finally I found out that one of the plug leads was severely corrodated and, after trying to pull it from the ignition's distributor cap, it broke off. It took some effort to get the remains out of the cap. I tried to ghet a new plug lead, but in Holland plug leads cannot be bought seperately and a replacement set had to be ordered. I managed to alter an old plug lead lying around and replaced the broken one. And yes, it fired up finally. Since then it rund much better, i was able to turn the idle down again without the engine stalling, and it runs much better now. Problem seems to be solved.

[Terry]

Happy to hear you've sorted it mate.