No Spark - help!

[Logana12]

Hi all

So my Austin 12/6 does not want to play ball. Before I bought the car I was aware it had a starting issue, but was told it had been fixed when it was delivered to me...

So the problem is that there is no spark getting to the plugs... the car has new spark plugs, a full set of new ht leads and all connectors, a new distributor base plate, new points, new rotor arm, new condenser, new coil and cable to the distributor. Anything else remaining has been cleaned up and has good clean connections.

I can prove power is getting to the distributor but after that I am at a complete loss!!! The engine just turns but does not fire...

Does anyone have any ideas??

Thanks in advance
Brian

[Logana12]

So, having started at the beginning and gone through everything again over the weekend, we re-did the points and hey presto, we got a spark. It still wouldn't start, so we drained off the carburettor and tried again, after an extended crank time with the help of another battery it fired into life!!! Yey!!! However.... She is still not starting well when cold.

With a brand new battery (480A) she will not start cold. As soon as I put on another battery in line, she starts (eventually). Once she has been running for 10mins plus and is warmed up, I can switch her off and restart her. She starts instantly!

Any ideas??? Fuel flow? Fuel quality?? Could there be drag in the starter motor when cold? If anyone has experienced this or similar I would very much like to hear your thoughts...

Brian

[SimonB]

Hello Brian,
I've just seen your post. Seems like your sparks are working so I what condition is your carburettor in, any play on the throttle spindle? If all OK are the jet sizes right? Does the choke work? I had my carb overhauled by David Jones (Page 12 in this months mag) and it made all the difference to cold starting as well as general running.
Regards
Simon

[Logana12]

Thanks for your reply Simon, I've since found the starting problem to be a problem with a bad earth on the starter motor. This I have fixed and it has improved the issue. However the car has since developed another issue where she is dying randomly when driven (not ideal) and has a very poor idle with excessive smoke under acceleration.

So having stripped the fuel pump and determining that it was in good working order I turned to the carburettor as you suggest... I was not happy with its setup as the mixture screw was having no effect on the idle, and exactly as you mention, there was play in the throttle spindle, so probably letting in air.

I have since sent it away to David Jones and he has found immediately that the slow running jet is the wrong size and significantly too large, and the capacity tube is missing altogether!!

So I am hopeful that this will prove to be the answer to my running gremlin and I will get the car reliable in time for spring!

I will update this post once I get the carburettor back and tested...

Brian

[SimonB]

You'll be amazed with the difference it makes, he sent mine back all set up, didn't need any adjustment at all, can't recommend him highly enough and the difference to the car is amazing.
I hope you find the same.
Regards
Simon

[Logana12]

Good Morning All, I trust everyone had a good Christmas!

So, the plot thickens! I have received the carburettor back from David and fitted it yesterday... however it is still not running right. The idle speed is still significantly too high and I believe it to be over fuelling (black spark plugs). Given that David had the Carb on his engine working fine, it must be something else. But I cannot for the life of me work it out. Essentially, the only way i can get the revs to lower to what I would describe as a satisfactory level is to operate the choke to approx 40/50%, thus reducing the airflow into the carburettor, but clearly this is not correct. I have checked and rechecked the default positions of the throttle and choke butterfly valves and they are both correct (Throttle almost closed and choke fully open). I have also looked at the throttle stop screw and the adjustment of the screw that rests on the cam for the choke butterfly, but to no avail. Furthermore, with the idle running high, when accelerating the engine feels “lumpy” again suggesting it is over fuelling.

I am frankly out of ideas as to how to reduce the idle on the car!

Am I missing something here?

[Shortstroke]

You say it is a 6 cylinder, has the timing chain slipped?

[Martin]

I think you need to do a compression test on all six cylinders. This will give you a good idea if your engine is capable of running properly when everything else is set up correctly.

[SimonB]

I agree, you need to get back to basics, compression test, timing check. Disconnect accelerator linkage and choke, check the throttle butterfly is completely closed.

[SimonB]

I agree, you need to get back to basics, compression test, timing check. Disconnect accelerator linkage and choke, check the throttle butterfly is completely closed.