Help! My 1275 mini has running problems!

[colmat]

Does anybody have any suggestions as to why my Mini will not run properly at anything over 3000rpm. She runs fine at idle but just breaks down under load.

Any help would be much appreciated!

[annodomini2]

We'll need a bit more info,

Carb, SPI, MPI?

Points or electronic ignition?

[colmat]

Hi, It's running a Metro 1275 engine and gearbox. It does not have electronic ignition and has a single carb.

It was fine on the drive to work but ran like a pig on the way home. If I keep the revs below 3000 its runs ok.

[Shoot Blair]

Get a timing gun on it and look what happens as you increase the revs. My guess is that the mechanical advance is stuck.

[annodomini2]

colmat said:

Hi, It's running a Metro 1275 engine and gearbox. It does not have electronic ignition and has a single carb.

It was fine on the drive to work but ran like a pig on the way home. If I keep the revs below 3000 its runs ok.

You sure its not electronic, most metro lumps were factory with electronic

The dizzy will have a big black plastic lump attached to the side, although it could have been changed.

[DanGT]

I could spend the rest of the day making a list. But hear are some easy checks. Dizzy cap got a crack in it?
Oil in carb pot at right level?
Battery connection inc earth all good?
Points in good condition?
Leads ok (see if you can see sparks coming off them at night)?
Water/damp got in any were?
Dizzy fixed down ok (not moved)?

Hope this helps

[colmat]

This car is driving me mad!! I had a poke about under the bonnet and the problem cleared.. But guess what. It's back and my poking about does not seem to help. One observation is that the car is running very rich, The plugs are black and so is the exhaust. I have tried to weaken the mixture but there does not seem to be any more adjustment on the carb.

Any suggestions would be gratefully received

[OldtimerJohn]

Don't forget that with the modern su carb with the mixture screw on the side, it works opposite. ie.. to weaken the mixture you unscrew the screw anticlockwise!

[ginettajoe]

colmat said:

This car is driving me mad!! I had a poke about under the bonnet and the problem cleared.. But guess what. It's back and my poking about does not seem to help. One observation is that the car is running very rich, The plugs are black and so is the exhaust. I have tried to weaken the mixture but there does not seem to be any more adjustment on the carb.

Any suggestions would be gratefully received

My guess would be that the stabiliser rubbers were weak or completely shot, and/or the bottom stabiliser bracket is broken. This allows the engine to move backwards, & the jet on the carb becomes bent and doesn't return to its intended position, .... in other words, it is like driving with the choke on! When you were fiddling, could you have pushed the jet back up?? Just a thought!!

[ginettajoe]

ginettajoe said:

colmat said:

This car is driving me mad!! I had a poke about under the bonnet and the problem cleared.. But guess what. It's back and my poking about does not seem to help. One observation is that the car is running very rich, The plugs are black and so is the exhaust. I have tried to weaken the mixture but there does not seem to be any more adjustment on the carb.

Any suggestions would be gratefully received

My guess would be that the stabiliser rubbers were weak or completely shot, and/or the bottom stabiliser bracket is broken. This allows the engine to move backwards, & the jet on the carb becomes bent and doesn't return to its intended position, .... in other words, it is like driving with the choke on! When you were fiddling, could you have pushed the jet back up?? Just a thought!!

Sorry, I should have asked what carb you were running, if it is an HIF carb, then ignore my suggestion!!