30 sport coupe

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dronedog

Junior Member
my dad has an original 30 sport coupe. just recently the engine began cutting out while riding down the road. before he can get off the road, it fires back up. backfires and runs fine for a while.
he thought it was the carb flooding the engine so we put in a new rebuild kit. i did not think that was the case but the carb was leaking gas and needed a new float valve anyway so we may as well do it all. well the leaking is stopped. the engine will sit and idle great. run around and go about a mile, then it wants to cut out, no warning, just dies but picks it back up, backfires and runs well again for a while.
to me it sounds like there is a firing problem and not a carb issue. but not sure where to look. i have always heard a condenser or coil just goes bad and the car would not run at all. not sure if that is true but what i heard.
i would appreciate any suggestions on what to look for. carb float set too low? too high? spark issue? wire grounding out?
thanks
dog
i did tell him to try taking off the gas cap just to see it was venting. but it would seem to me if that was the issue, it would not fire back up before he gets off the road.
 
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As soon as it acts up check the spark by holding the coil wire 1/4" from the head and see if you still have a strong blue spark. If not you might try a new condensor first. I would doubt the coil went bad, but anything is possible.

Do you have the small stand up filter in the gas tank valve? If not, then I'd install one.
 
I had a similar problen on a 28 leather back. start and idle fine, went a mile and the engine would die. the owner has had the car since 1963, we went thru all the normal trouble shooting, and found the gas line was restricted, and the bottom of the tank had 1 inch of sediment. We flushed the tank with kero, installed filters, new shut off valve cleaned fuel line and carb, car runs perfect. this car is driven 1000 miles each year so watch were you get gas.

mike
 
all these guys are on the right track forsure. I just went through a huge issue with my car not starting and finally found out it being a bad carb but everything appeared to be alright. Start with the small things first like gas restriction.....then move on to see if you have spark everywhere ie. coil,points,plugs ext... could be a case of bad gas but I wouldn't think thats your problem. Keep us updated on the results so it will help other people down the line.
 
Ditto the above advice above, sounds like it's not getting the fuel when demand goes up.
Just for grins and giggles: Shut of the fuel and loosen the connection to the sediment bowl, undo the connection to the carb and rotate the fuel line clockwise to where the carb end is now above the hood line.
Have someone open the fuel valve, and blow through the line into the tank. you should hear bubbles in the gas tank and a hissing of the vent in the cap as the air you install tries to get out.
If you can't do this you may have something blocking the line. If you can do it: shut off the valve an reconnect everything in reverse order, then try and run her down the road. Let us know how this turns out. Good luck!
 
thanks. i will start with the fuel line. we could have moved something when putting it back together. i don't know if he has tried removing the cap yet but i will find that out also.
 
still having an issue. he took the cap off and the car ran fine for a mile. then it quit. it only quits a little bit and then it backfires and picks it up. it runs fine again for a while and then goes thru the same cycle. cuts off and then it starts right back up before he gets off the road.
 
Had you taken the distributor out just before this started? If the end of the cable is screwed in too far, it could possibly cause this sort of intermittent problem.

Look for loose connections in the terminal box, on the coil, on the switch and on the ammeter.

Joe
 
make sure the gas line isn't pushed into the sediment bowl too far. The line should only extend about 1/8" past the ferrule. If it's longer than that saw off the excess. What happens is that you slide the ferrule onto the line then stick the line into the sediment bowl then tighten up the fitting compressing the ferrule onto the line BUT the line is up against the inside of the sediment bowl restricting the fuel's ability to get into the line. This creates a gas starvation, lean, situation where the car has enough fuel to idle nicely and will run on the fuel in the line but eventually starves the engine. The telltale sign is the backfire. This is assuming you don't have junk in the tank that is floating over and shutting off the outlet which creates the same situation.
 
Our Roadster exhibited same symptoms this spring. The fix was to drain the gas tank, remove the gas shut-off valve, insert a "gas tank screen" into the gas shut-off valve and then reassemble. The pencil-thin screen prevents the carb from scavenging gas off the bottom of the tank, which keeps that little crumb of rust or the gas gauge gasket you dropped into the tank from shutting off the gas supply. Try this easy/cheap fix early. It worked for me -- after lots of more labor-intensive stuff and plenty of frustration on a very long drive home!
 
Thanks for the help. he called me yesterday to tell me he went driving and shut the fuel rod all the way down. when he did this it popped a couple of times but it did not cut off. you would think with the gas off it would cut out. i guess i need to ride with him and see exactly what it is doing.
since we rebuilt the carb, is it possible we left the balancing screw to open. it was set at 1/2 turn on the old screw when i took it out. when we put this one in, it seemed to idle better with about another 1/2 turn. does this possibly cause it to flood while driving or when it gets hot? wondered if maybe we turn it back in and then see about opening the fuel rod a little.
 
i believe what you are calling the fuel rod is also called the choke rod which connects to the GAV. (gas adjusting valve)it does not shut off the fuel to the carb only the fuel shutoff will. check out this carb link it may help explain somethings. Float Valve and Float (Model-A.org)
 
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If all above doesn't solve it. Check points gap (.18-.20). Check timing. Check to see if "pigtail" wire connecting points to distributor plate is tightly connected and not shorting out.
 
I may of missed it, but has your Dad tried changing the condenser? I had a similar problem when I first got my '30 Sport Coupe some twelve years ago. I had back firing and than the car stopped. I changed the condenser and no more problems. If you have checked out all the carb potential problems, be sure to try the condenser cure.

I also have had the pigtail screwed in to the distributor and it would short out when making a hard right turn. No backfiring with this problem though.
 
great info on that site. from reading it, i believe our float valve is set wrong. we will have to get a kit to check it. thanks again.
 
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