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MG Midget and Sprite Technical - Mg midget 1500 big problem

A view weeks ago a had to take the engine out to change the clutch. After I build the engine back in the starting problems began.
A summary of the setup I have:
1500 1976
Electronic egnition
Stromberg cd 150 carb
New sparks
New egnition coil
New egnition leads
Carb is cleaned

Problem when I start choke open or closed the rpm needle start jumping from 0 to 500 rpm and that’s it.
She runs very rough, then when the engine is hot the engine runs a little better but not oke. I really do not know where to look.

Greets
Jan
Jan Jacobs

Hi Jan
offering help remotely is always a case of starting with the obvious. But without wishing to offend, have you looked at the basics, coil wires round the right way, plug leads the same, earth strap connected ?
I assume you are getting a spark and fuel ?
Anyone who can take an engine out and change a clutch, would have thought of these things of course, but starting at the basics, has often helped me along.
There are far wiser folks on the forum than I, so help is on its way.
regards
peter

P Bentley

Hi Peter,

Indeed I checked the basics all is well attached, I have spark, I have fuel, the earth strap is fastened well. But still!
Jan Jacobs

Jan,
as with Peter I don't mean to offend but he posted as thought, check the basics and check again, a number of times and only recently problems have been resolved on re-checking what was thought to have been fully working, I know I've missed the obvious until it has been pointed out by someone else, more than once.

Note I am certainly not one of the wiser posters here so just my general thoughts now.

The engine starts but does not run well. By what you've put and the usual run of events it is more likely to be electric ignition side rather than carb side (or a combination of both or could be something different altogether).

If using the choke made no difference to how it runs then that might point to a choke or carb problem more likely.

I note you have electronic ignition and jumping rev counter - igniter heads have delicate wires that can get trapped, scuffed and nicked.

I also note you cleaned the carb so check it has been refitted correctly and choke set correctly.

Refer to the Driver's Handbook to set up the carb and other components.

New parts can be faulty from new so check them and if possible replace one at a time with the previous old parts that were working, that is replace a set of parts one at a time (example - HT leads/plugs/coil/etc.) and then one part in that set at a time if you want to find the single culprit.

Nigel Atkins

As Nigel says, new parts can sometimes cause problems.
Dave O'Neill 2

Check your ignition leads are connecting properly and are in the right position. try installing the old spark plugs.
Dominic Clancy

Does not sound like a big problem.
First rule is “all new parts are at fault”
So if possible use known working old parts to check.

Chuck in an old ignition with old leads and old plugs.

As long as you get oil pressure and don’t hear strange metalic sounds it can’t be a big problem
O K

I'm concerned about the jumping tacho too. But are you sure the manifold gaskets are airtight?
Greybeard

I'm thinking out loud . . . . electronic ignition modules do funny things in the presence of tacho modules, especially if the tacho connection is on the wrong side of the coil terminals. When that happens, the electronic ignition can trigger off the tacho, also causing the tacho to jump around. I think. Maybe. Possibly . . . . .
J Thomson

My electronic ignition needed wiring in particular ways depending on the model year. My 1500 has a balista (I think thats right ) coil. I see you changed your coil. Are you sure its still the same as before?

Dave
Dave Squire

This thread was discussed between 21/05/2018 and 22/05/2018

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