So, my son buys a '78 'B' (yes, I'm jealous)and picks it up this morning.

It's been running daily, or at least wee(a)kly.

He starts it and starts to drive it home...five miles, or so, it backfires twice and stalls...won't re-start. (Tows it 10 hours home.) Dad, the car won't start! Turn it over, sure enough, car won't start.

Dad checks for fuel flow... disconnects fuel line and turns key, accidentally turns key to "start" and car fires right up! Dad reconnects fuel line, touches the key and vroom, car starts instantly and runs at high idle. uummm.

Car runs for five minutes, or so and starts to die, touch gas, and engine dies. Turn key, not starting...

So what's up?

Car has a weird ignition "module" (aftermarket, according to PO) All of my experience is with 1967-1969 MGBs, no fancy ignition stuff there.

Can the choke system on the Stromberg carb cause this sort of thing? (stalling when it gets warm)

check the fuel pickup tube in the tank. Some gas is probably varnished over the plastic filter on the end of it. Mine did exacly the same thing when I first got it running. Go about 1 mile and then it would quit. After sitting a few minutes with the key in the on position, it would crank right up and go another mile. When I took the pickup tube/sending unit out, I couldn't even blow air through it. I used the end of a small screwdriver and an exacto knife to re-open the little slots.

Definitely the most likeley cause, have had the problem myself and know many others who have as well.

IN addition to old gas gunk can also be sediment from a rusty fuel tank clogging the pick up or somewhere along the line.

Be sure to check the tank well before you start driving it. Mine had a layer of old gas that had turned into a sticky substance that clogged my valves after a few miles.

OK, will do. Thank you. Will post back and also post photos and have son create a user name here.

Well...

Took the intake tube out of the tank, it was very clean. Disconnected fuel line at carb, and got a steady flow.

Hooked coil directly to one cylinder, engine hit.

So, we have fuel and we have spark, or do we?

Put things back together and found a black box on the fender wall, it's a "piranha ignition system" jiggled the box around while we tried to start it and car starts! Only to end a minute later with a backfire from the exhaust.

What's a piranha ignition system? My experience is with '67-69 B's, not this.

We've looked at Moss catalog, external amplifier on the distributor? This is new to me, and at only $400??? What the heck?

Is this thing preventing the car from running?

Not sure about that one. Does it still have the opus electronic ignition? My car has a standard 25D4 distributor installed by the PO. I'll be adding a pertronix to that soon.

Now that I know what an opus ignition is, yes, it's still there. Vacuum line is not present. Six wires from black box spliced in at various locations.

Is the 25D4 an earlier distributor, was that done to get away from the fancy "amplifier"?

Yes, and yes. More simplified 1 wire hookup. Just like the older MGB's. Get one from Tony, or whoever you get used parts from. Not sure about the difference in advance curves aver the years, but just about any old MGB points distributor will work. Opus sucks, and is probably the problem here.

Plainly said! What a mess under the hood. Google leads me to find piranha ignition system was made in UK, bought out and bought out again!

I can chime in here...I had a pirhanna connected to the stock distributor. I think it was an aftermarket optical pickup of some sort, kind of like a pertronix. Mine was running the car just fine when I removed it. could be a bad solder joint. I can't remember what condition mine is in...I could send it if there's no broken wires.

get a 25D disty, and teach your son to keep the points lubed and set.

I have a '79, backdated to about '71. twin SU's, and 25D. As long as the points are set, it runs like a champ.

sjd

And, either a points file or an extra set of points and a feelers guage tucked in the dash for emergencies. Best $10 insurance you'll ever buy. Works for the fuelpump (if original) too.

I'll play th' broken record... retrofit an older diz and points. The "black box" units are fine when they work... that one could be getting warm and with thermal expansion a discontinuity may be created. Too much reliance on "solid state" widgets in cars designed with mechanical triggering is unnecessary, IMO.

An emery board and a matchbook can usually get you home in a car with points. A AAA card is the only bail-out option with a smart box iggy.

Agreed on all three counts. Points I can understand and teach him the same. I appreciate the input. I'm going to start scrounging for a 25D.

Doc, I couldn't agree more about the emery file and a matchbook cover, those two things saved me once, although nowadays, I can actually afford the extra set of points like Kenny suggests.

Steve, how long have you had the 100-6?

I talked with Tony...he sent most, if not all, of his dizzys to a guy named Jeff in Minnesota!

So I called Jeff, and found his website . We ended up ordering a rebuilt 25D, new coil, wires and plugs.(In for a penny, in for a pound, as they say.)

I'll report back after the swap.