Technical Tech help

[moretti124guy]

I just picked up a 1974 X19 that is in very good condition. The carb was recently rebuilt and the car was running great until the other day. I was on my way home on the freeway and the car just stopped running, it sputtered and just died. No loss of oil pressure, and the temp was normal. So I tried to restart it and it cranks over fine, starts to start, and then sputters and backfires before shutting off. I am thinking it may be a fuel pump, but I wanted to see if anyone had any ideas before I took it apart. It is a stock 1300, that has been "de-smogged" and has a electronic ignition.

Other than that any ideas?


Michael
1974 Fiat X1/9
1969 MINI

 

[Brooa]

you could try pulling the fuel return line off the carby and seeing how much fuel is flowing through? this should give you a good idea of fuel flow etc. you may just find theres a blocked filter or something.

 

[jimbro1000]

Check the standard 3 things first.
1) Fuel
2) Ignition
3) Compression

Sounds like you're lacking one of the three - my guess is on ignition, either the timing is out or the HT side is breaking down.

 

[moretti124guy]

Ok so I tracked down the issue it was a bad rotor. The rotor in the dist was burned or melted on one side. I replaced that and the cap and it fired up perfect, until it started to idle higher and higher. I attempted to adjust the carb according to the manual, but it just keeps climbing and it settles at almost 4K on the tach. Anyone have this issue before????? I am at a loss as I have adjusted the carb any and all ways it is shown in the book.

 

[jimbro1000]

The only thing I can think of is that the carb throttle butterfly is not closing properly. Either the shaft is bent (unusual on these carbs but it can happen), the autochoke (if you have one) is pulling them open slightly or the throttle cable itself is adjusted wrong.

It could conceivably be a little too much advance on the ignition also encouraging it to accelerate but it shouldn't make that much difference.

 

[moretti124guy]

I pulled the carb off this afternoon, the secondary butterfly is not closing all the way without help. It is staying open about 1/8 of an inch. Is there a better aftermarket carb set up I should be looking for?

 

[jimbro1000]

The DMTR/DATR is a very good carb to start with. Without going to seperate twin choke carbs there really isn't much you can do.

If you want to investigate the twin carb route then try to find a pre-EFI MG Maestro in a breakers yard and nick the carbs off that. They are the right size and just need a little re-jetting on a rolling road to get them perfect. You will need a proper throttle linkage and a pair of manifolds to go with them.

Beyond that you are looking at converting to fuel injection with throttle bodies.