engine losing power

[marc]

My moggie has developed a problem.

It starts fine, and drives well for the first half mile or so. Then the engine cuts out, and although restarts easily, cuts out again as soon as you lift the clutch and make it work. My guess is that it may be the head gasket, but the oil and water look good, with no cross-contamination.

Has anyone out there any ideas?

[brixtonmorris]

may be the choke is stuck open. could be the coil, or the oppersite to choke stuck open, a lack of fuel for some reason

[Kevin]

If it starts and runs fine its unlikely to be the head gasket, does it only happen once its warmed up and does it still happen if you raise the revs when using the clutch ?

[marc]

Thanks for your replies.

I don't think that the choke staying open is the problem, as you can see it shutting, but it is certainly worth me checking inside the carb. Also the fact that it happens suddenly I suspect would not point to this.

I guess the only way to check the coil is to try another one?

I suspect that the problen may only be apperent when the engine has warmed. By revving the engine when I raise the clutch I have so far been able to struggle home. That it revs freely when restarted, I have taken as a sign that the fuel is OK.

Marc

[winger300]

have you checked the timing? My dizzy slipped once, and i had no idea what had happened, but the car was really difficult to drive without stalling, but the engine revved really smoothly.

[turbominor]

my last moggie had a similar issue, every thing checked out but it kept spluttering to a hault afery mile or so..

in desperation i decided to dip a stick in the tank to double check the level and as i removed the modern lockable cap there was a big hiss.. turns out the vent hole had become blocked and the fuel pump was sucking the petrol out but no air was getting in causing a semi vacume....

[MrA.Series]

Same happened with me! The rubber round the cap used to swell up in the wet with mine, otherwise it was okay.

[jbennett]

Try replacing the rotor arm. Your problem sounds very much like the problem I had and which was discussed at some length a few weeks ago on this message board. If your rotor is a newish one and made from black coloured plastic, get rid of it and get hold of an old one from the 60's or earlier. The modern rotor arms break down far quicker than the old ones and the result is an engine that stops under load when warmed up and eventually cuts out for good.

[rayofleamington]

There's a whole heap of things, but checking the timing isn't a big job so it can't hurt to do that first (and it should be done regularly anyway)

I also had a failed rotor arm, but they give a lot of missfirring, so I'm not sure that's your problem according to your description. If you had lots of missfiring then check this urgently.
Also faulty coil etc could cause a weak spark, therefore upset the engine under load.

Fuel starvation needs to be checked - as the engine will still rev up, but not drive under load. I've seen this from a temperamental petrol pump which started and stopped - getting worse as it warmed up. Do you know if the pump is fine?
Petrol tank vacuum is also possible but usually only after you've used a lot of petrol (ie not after the first half mile).
Many other things could cause fuel starvation, so it'll all need to be checked.
Stalling can also come from a sticking throttle slide which then overfuels the engine at idle causing stall. This will get worse in the warm as it's like having the choke 5 times more open than you can do with the choke cable.
To check it, take the airfilter off and push the throttle slide up. It should have a resistance caused by the damper. When you let go, the damper should open and the throttle slide should snap back down with a 'plop'. If it comes down slow, or sticks then it usually needs only dissassembly and cleaning.
However if it always restarts easily is a tough one - nearly all faults mentioned would also be evident when trying to start.
Had you left it for seconds or minutes before restarting ( i would guess that you restart immediately?)

[skater]

hi
i had the same problem, and its was being caused by the
condenser, fitted a new one and no more problems

skater

[Kevin]

Skater did you not find that the points were not lasting long, discolouring, burning out quickly as they are all signs of a conderser going home.