Good morning everyone, I'm just about at my wits end with my flatty. I have a '49 8BA with dual carbs, MSD ignition, and Fenton headers. Within 15-20 minutes of driving, the engine stalls out and won't restart. If I wait 5-10 minutes, I can restart it but it won't run under load for more than a block before stalling out again. What I know: Temp guage never gets past half (though I've seen it pegged in the summer) A small amount of steam comes from the breather Engine is running rich; there are dry black deposits on the spark plugs Fuel pump is working and there is a regulator Header installation was the latest change to the engine Fuel lines around the block are warm to the touch, but not hot No oil in the coolant No coolant in the oil Any help would be greatly appreciated! -Stefan
I maybe a fuel problem,ya don,t want fuel lines next to exhaust pipes.Drain tank and blow gas line back to tank.
MSD units are susceptable to not having good grounds make sure everything is grounded to a good ground, box, dist, even advance plate to dist, dist hsg too block, block to frame............ get the running rich corrected, jets and carb tuning, are carbs synced............
Thanks guys. Carbs are 94s at 3-3.5 psi using a mechanical pump. I've emptied the bowl to check refill. Fuel lines are not really near the headers. I mentioned them to possibly rule out vapor lock. As I said, they get warm but not hot. I did all the wiring myself and know I have a good ground. The engine feathers out over a minute not instantly which suggests it isn't an electrical issue.
Roseville Carl is right...Good grounds all around are a must.....Mine are on bare metal, with "star type" washers added. Adding the driver side exhaust could be getting the fuel line just warm enough to vapor lock; Fords were plagued with the vapor lock issue just about all the way thru the flathead years. Ditto to all the carb setup advise,....and if using Strombergs, (new or old) fuel pres. needs to be no more than 3.5 lbs. After getting the carbs set up, try installing a 3 lb. elec fuel pump as close to the fuel tank as possible. That cured my issues with the 47 Ford I had. 4TTRUK
at the time of failure, do the accelerator pumps still shoot gas? any fuel dripping down throats of carbs?
Check your gas cap to make sure it is venting. You could determine if this is the problem by removing the gas cap next time it conks out. If she runs with the cap off, you'll know.
Something else that would help would be to wrap heat reflecting material on the fuel line, where it runs along the frame rail.... Happy Roddin' 4TTRUK
Im with Jack on this one. Im running dual Strombergs, electric fuel pump and fuel regulator and sequential carb linkage.
I've noticed occasional gushes of air bubbles into the fuel pump's jar. It definitely feels more like fuel delivery issues rather than electrical. It doesn't cut out but rather sputters for a minute before dying. Just how hot do fuel lines need to get for vapor lock?
bubbles would indicate air mixed w/fuel. suspect something like a bad fuel pump flexible fuel inlet hose...jack
First you have to determine if you have a fuel or ignition issue. As soon as it craps out open the hood remove a spark plug wire and check for spark by attempting to start the engine and holding the contact of the plug wire slightly off the head surface. If you have ignition you should see a good white/blue spark. If you see a weak orange spark there is a potential ignition issue but the next check is the fuel. Remove the air cleaner. Open the choke plate, look in the carb while opening and closing the throttle quickly, you should see a stream or drops of fuel spraying into the carb base. If you dont, attempt to start the engine with some spray either starting fluid. If it starts and dies its a fuel issue. If you have fuel and it wont start on starting fluid then you know its an igntion issue. Now if it starts on starting fluid and will continue to run with random spirts of starting fluid it may be necessary for you to trace the fuel lines to make sure they are not crossing close to a heat source like mufflers or dual exhaust pipes. This will make your new yuppie fuel percolate and this may be the source of your problem. Try this approach before you tear everything appart.
Yes modern fuel is very susceptible to vapor lock. And to compound the problem most fuel right now is still winter blend which is even more likely to vapor lock.
Story time. I had that stoping problem,start up run awhile and quit.I drove home with 1 gallon jug tied under hood had range of say 10 miles did i few times to get home hoping for anotther gas station.The problem was a small gas filter with a micro cantrage,looked clean but could not blow thru it. I don,t think you need a regulator with mech pump,they are for eletric fuel pumps,I,m runing 2 lbs with 2 97s and electric pump at tank.Your gasket on pump maybe leaking,rotted gas line with hole in it.Another thing is rust it never goes away.
You didn't say if it was 12 Volt or still 6 Volt...Mine is a 12 Volt conversion..I run a Carter electric fuel pump mounted just in front of the rear spring perch, using a Holley fuel pressure regulator set at 2.5 PSI & an oil pressure Safety Switch, with a Holley fuel filter...It sounds like it could be fuel, flex line sucking air at the firewall, or a coil going bad, or even a condensor problem... Jim
Once again, thanks guys. The coil is about 3 years old and was replaced when I converted to 12V. I have a pressure regulator because the mechanical pump was able to produce pressures over 5 psi. Rust in the pump jar is common, but has never caused a problem like this in the past. I'll also have to check just how close the driver side exhaust gets to the fuel line (I completely forgot about it until today) Also, definitely not the coil; I tried a new one today.
I go with the fuel pump . My flathead has done the same thing. Pump gets hot after about 15 min. and pressure drops from 2 1/2 to 0. Have changed to Faucet 2-4 lb.pump,will know more in a day or two.
Do what Dick Spadaro said. It does sound like a classic dying coil, which will give a thready yellow spark that won't run the engine when hot. If the air bubbles ar pointing to your problem...either heating up back there somewhere or you have a leak/pinhole somewhere behind pump. If fuel becomes the suspect, get some rubber hose and hookup pump to a lawnmower tank or Moon tank or such and go for a ride to see for sure.
The Jalopy Journal
