Lumpy under acceleration.

[RobbieJE]

Hello, I am completely new to this, I have a 1967 2-door with a standard 1098, as far as I am aware. I took it for a little drive on Sunday and it became progressively more lumpy (stuttering) under acceleration. I don't have a clue where to begin solving this, although I have found the online workshop manual, does anyone have any suggestions? Apologies if I have put this in the wrong place.
Thank you
Robbie

[martin418]

i had exactly the same thing on my car and it was a faulty new condenser , i fitted and old one i found in a box !and it's run fine ever since

[dalebrignall]

have you changed any parts recently . there is a lot of bad ignition componants on the market , for decent stuff go to accuspark or distributer doctor , it sounds like your car could do with a tune up .its difficult to diagonose problems like this could be 101 things .

[RobbieJE]

Assuming it does just need a tune up what should I be checking first?

[Trickydicky]

You could start by re gapping the points (15 thou) then give the plugs a clean with a wire brush and regap. If it has not had a service for a while a new air and oil filter and oil change wouldn't go amiss. (20w50 oil)
If you need a condensor give this chap a call, http://www.distributordoctor.com/distri ... ensers.htm

[bmcecosse]

Air cleaner - is it clean? Carb - does the piston rise and fall easily, and a teaspoon of oil in the damper. And check the 'choke' is going fully off at the c arb. Spark plugs - what colour are they ? Do they look 'recent' or ancient.. HT leads - good condition? Or old and knackered. Then you are into the dizzy - points gap and condition, condenser, rotor arm - clean or filthy, same for inside (and outside) of dizzy cap. And - the general condition of all the connections around the coil and dizzy. Check/adjust ONE thing at a time - and then make sure it still starts and runs before moving on to the next check.

[RobbieJE]

Thank you all for the suggestions, that is a lot to be getting on with. I'll get back to you when I have tried them or when I have some questions regarding doing them. Would it be worth checking the valve gaps and do I require a specific tool for removing the Spark plugs?
Thank you
Robbie.

[Dean]

Most socket sets have a spark plug socket. It is basically a little deeper/longer than your normal socket. If not your local motor factors will do one.

[bmcecosse]

It's always worth checking the valve gaps - just need a feeler gauge for that - set exhausts to 15 thou, inlets can be left at 12 thou. Spark plugs need a special 14mm spark plug socket - or a basic hand tool for the job.

[Monty-4]

Might be worth asking your local branch for help, somebody might just come out and show you all these things.

[RobbieJE]

I now have a Spark-plug socket, are the valves arranged IEEIIEEI?

[bmcecosse]

No - quite the opposite...... Look at the manifolds !

[RobbieJE]

Thank you, yes I see now. The air filter seems quite dirty, the inlet is pointing right at the exhaust manifold should I move it? I also seem to be missing a Jubilee clip on the breather pipe. Where am I looking for the Carb piston?

[RobbieJE]

Also should there be a rubber seal between the housing and baseplate of the air filter?

[bmcecosse]

Run it without the filter till you get a new one. There should be a rubber ring - but it's hardly critical. Remove the air filter casing - the piston is right there in the mouth of the carb and must lift and fall easily. Search Google for a free download of the Workshop Manual.

[RobbieJE]

How far is the Carb piston supposed to move? If I push the piston lifting pin it rises then, with the briefest of pauses, it falls back down after releasing the pin. The spark plugs I would describe as light brown with a layer of soot over the top, although I did manage to stall it a couple of times reversing into the garage.

[bmcecosse]

Lift the piston with your finger - it must go right up - and then fall down. Plugs sound ok.

[RobbieJE]

There is quite a bit of resistance when pushing it upwards, it falls back down with a medium speed.

[RobbieJE]

I also took the rocker cover off so I could set the valve gaps, there seems to be a very thin layer of mayonnaise on the rockers and inside of the cover. Also I am struggling to undo the lock-nuts.

[bmcecosse]

The piston sounds ok - to really check you first remove the little damper piston (black 'nut' on top). The rocker lock nuts don't need to be touched if the gaps are ok! Just check the gaps first. 1/2" AF small ring key for these nuts. Just wipe away all the mayo - but an oil + filter change could be a good idea.