'31 Tudor AV8. 59 AB, '39 trans, 38 banjo rear, 2 94's on an edmunds manifold. Engine has been running fine for 2 years. You know...go to garage with a beer, start it up and grin at it while checking everything over and such. Good flatty, 150 psi in all cylinders. Everything has been good. Been building it for 6 years. Been JUST driving it around the block and short trips for the last month. Blew the '38 trans that was in it. Take all apart, put in fresh '39 trans. Start up and start going again. Took it for a couple mile spin for an errand and when I came out 2 mins later, it would not start. Spin over fine, just no evidence of spark. Carbs leaking out the bottom from too much fuel while trying to restart. Mop it up and grab a bite with my friends across the street. Come out, starts fine and drive it home quick. No issues. Take it to my buddy's house about 2 miles away on fathers day to show him. Runs well. Idling great in his driveway. Go to leave and notice that it breaks up a little on heavier throttle so I back off while scratching my head on the way home. Light throttle okay. Heavier throttle, not so much. More breaking up. Get it home and put in garage. Cut engine. Will not restart. Same symptoms as last time. Go out with the family for fathers day. Come home late. Ex-wife giving my shit again as usual so I decide to take it out for a spin to blow off some steam. Same issue with throttle. Get on it a LITTLE bit and it breaks up. Light throttle okay. Get four houses away and it dies. Dead. Engine just quits. I pull over and try to figure it out. Plenty of fuel. Jump a hot wire directly from battery to coil. Nothing. Push it home (luckily downhill and coast into driveway). Park for the night. I'm thinking spark so I change out the coil and condenser yesterday. Starts fine. Idles great. Take it out again up the block. Same issue with throttle. Heavy throttle, it breaks up. Light throttle okay. Get it home quick (again only four houses away) and back it into garage and cut engine. Will not restart. Spins fine, just doesn't fire. Go to bed disgusted. Figuring MAYBE a breathing issue so I take off the air cleaners. Starts fine today. Idles great. Take it for another four house spin. Issue with throttle seems worse. Get it home and engine DIES as I'm backing it into garage. Will not restart. Break out the meter. Got juice to coil and dizzy. Plenty of fuel. No issues there. Pull cap off crab dizzy. Cap looks good, Rotor looks good, points look good. Stock mechanical fuel pump working fine. Have pressure regulator set at 1 1/2 lbs. confirmed by gauge on fuel line at carb. Any ideas? Thanks, Andy
Been seeing this a lot lately on the boards I frequent. Vapor lock? This ethanol crap has been causing havoc in my 55. Intermittent dying when pulling up to a light, won't restart for 5-10 minutes. Falls on it's face above 4k rpm on one pull, strong as a bear on the next pull all the way up to 6k. Runs great when it's running great, if you know what I mean. Fuel pressure holds steady, even after it dies.
What do the plugs look like. Might be dumpin to much fuel and there might be a vacuum going on after you shut it off and it's flooding it. At low rpm it's somewhat fine then you get on it alittle and it breaks up, I would start with fuel bowls maybe they are stuck. I would think it's in the fuel and not electrical. Clean the jets check the accelerator pumps check linkage. Plugs can tell a lot as a lean and also to rich can sometimes have the same effect. To lean and it will break up because there's not enough air and to rich It can break up because it's foul out the plugs. But then timing can do wierd things too. Also how long has the gas been sitting in the tank. Bad gas can make you pull your hair out trying to figure out what's wrong and all it is old gas. But then again I haven't seen a rainbow in a long time so I don't know. Could be a bad ground. Carb gasket leaking could cause a vacuum leak lots could be wrong just dive in then and post how you got her fixed.
"Carbs leaking out the bottom from too much fuel while trying to restart" Shoudn't be. Power valves maybe working loose, their gaskets failing, diaphragm shot...? Or...do you have the inlet needles with rubber tips? Rubber dissolving? Sticking?
Sounds like a bum coil to me. I had the same thing happen to my 1949 Dodge. Drove me nuts. I actually sold the car before I found out what the problem was. I was really pissed at myself for finding out too late. Oh well....I was 17 years old back then.
Okay, diagnosis 101; Information, patients and plan ahead!! What do you have? Ignition is missing in post, do you have an ignition system? How does it look? Pics please Fuel pump? Old, new or don't know? Do you have a volt- or amp-meter in car? Vacuum gauge? Does it smell of fuel? Does it start on 8, when it does start? Do you have a fuel baseline on it or is it properly set up? How old is the plugs? Make? Did you rebuild carb? Is the float valves new? Is the floats? Is the carburetor insulated of the manifold! There is a reason for all the questions, and the answer tell a lot!! And it might be more then one issue!! So tell all, show all and the truth will set you free! No holding back!!
Average reading comprehension suggests that spark (or LACK OF!) is the culprit. Repeated. And again, in the 'Four House Road Test'. Finally, (again!) at the backing-in stage, second 'four house test'. Spark at coil and distributor...sound like condenser? Maybe fuel, but sounds a little thin... (that's cop talk by the patrolmen, usually trying to get noticed for detective!) How'm I doin'? Just in passing, (this isn't the problem, Chiro bypassed the root of power source with jumper) my F100 died suddenly, wouldn't start...ended up calling the ramp truck! Faulty ignition switch was the culprit. Ran fine, then MISS! Then fine again, then: Nada. Nix. Nothin'! (no jumper wire with me, either) It can happen... Shift! Damned switch was NEW in '74.......
Thot it was the coil. Replaced coil and condenser last night. Nope Ignition system: Ford crab dizzy, dual point rebuilt. Standard Motor Products 12 volt coil, internally resisted Fuel pump, stock mechanical off manifold, new Ammeter yes Vacuum gauge no Does not smell of fuel when running, only after dying when attempting restart. Banging on all 8 all the time What do you mean by "fuel baseline"? Fuel system is properly set up Plugs 2 years old. Garage run only for maybe 10 hours before taking to road 3 weeks ago for short spins. Champion H10. I have not inspected plugs yet. Carbs rebuilt. 2 years ago. Installed with plugs 2 years ago. Carbs insulated off manifold with 3/16" spacer. I suck at rebuilding carbs so I had my flatty guru, Bill Ketch, rebuild them for me. He knows what he's doing. Don't know about the inlet needles with rubber tips. See above about Bill Ketch rebuilding the carbs. But BOTH carbs failing the same way at the SAME time does not make sense to me. I did remove both carbs when I had the engine out to replace the trans. Reused all four carb gaskets (one above and one below each spacer) because they looked good and were not on there all that long before I took them off. Now I'm thinking they may be leaking and causing excessive vacuum leak. Is that possible that the engine will start when cold and then when warming up a little, dying due to progressive leaking of vacuum at carb bases? That just does not make sense to me either. Gaskets looked perfect upon disassembly which is why I reused them. Still scratching my head. Andy
Okay You did some work and don't ride on luck, very good to know. There should only be fuel outside the carb if you have a carb issue! If you have a vacuum leak, it would explain the issues when you get on it, but not the not-starting-at-all deal. If you have a moment when it decides to start, spray ether/starter fluid/brake cleaner/propane or the like there of around the base of carb, as a diagnostic purpose! But back to the problem at hand, A good rule of thumbs; If it's fidly, and can be massage to behave, it's mostly carb. If it runs under some conditions, like only cold or only in sunshine, it's ignition. And if it don't run at all ever, start with compression/mechanical inspection. But you are on to something, have you checked coil in any way, except does it get power? Did you check distributor for ground, and are all wires to distributor good/new? Does the amp do anything when it doesn't start? Dip, top out or no damn change? The "fuel base line" question, is to determine how far along you are in your set up. A "fuel base line" is when you call your flathead guru/carb guru/or just the service station down the road and ask: I got X amount of motor, Y amount of carbs and Z amount of cam, what jets do I need? This is very basic and it takes more then that. I did this with my carbs, and I went a little up and down till I got the right mix. But it cost me at least two sets of plugs to get it right, overfueling makes them foul, and I had to go for a different set (glow number). I needed to know if you had worked that issue out or not. But when you say it's set up perfect, it might be somewhere else that is more important to look first.
Also are you using the glass bowl style fuel pump. If so have you been watching the glass to make sure it stays full. Vapor lock can also happen. Also next time you shut if off and It won't start right away spray some staring fluid in it just real quick spray don't hold down the nozzle just as fast as you can just to see if lights off then dies. That can tell you all about a vapor lock or a flood. and also again how old is the gas?
Yes as the motor gets hot it could cause the gaskets to leak as metal moves from heat. Now I can't remember if there is more vacuum at idle or at higher rpm? But any vacuum leak will mess with the way the motor runs.
Check plug wires for arcing out? Night time mskes that easy. Old wires do break down... Check all connections to the distributor? Buddy didn't make show once b/c of those POS butt connectors. Wire came loose, but didn't fall apart. Lost power when it just ran a second ago... major wtf moment. I had a new Mallory condensor give me the exact same problem you described on my 8ba. 3blap.
You sir is on to something! More vacuum at closed butterflies, not to be confused. And I agree with the spray in the carb when it do not start, but I'm a big fan of checking all over from one end and then troubleshooting. And plugs out, and check them, pull can and pressurize the system to check for leaks, ad new fuel when I doubt and do from there. And just to make sure, crab style distributor is post "diving helmet" and pre Mercury style distributor, right? Or is it an updated "diving helmet?
Okay, the gas is not old so let's forget that one. The ignition wires are not old either. Plugs were a bit black so I replaced them last night and it didn't start at all. Crab style distributor rebuilt and set up on Sun distributor machine so that's okay. I will try the ether test for vacuum leaks if it starts today, but doing that always scares the shit out of me. Still scratching my head. Andy
Where is your coil mounted? I had almost identical issues with my 59A. Even replaced the coil. Every time the car quit on me, you couldn't touch the coil because it was so damn hot. The first coil I replaced was bad out of the box. And the second one had the same issues. I then remounted it so it catches air off the the fan, and haven't had issues since. Of course by the time I had done that, I had replaced the condenser, plugs, plug wires, and fiddled with the carb and all electrical connections, so it could have been a combination fix... I also know that if you hook up the coil backwards, it will work. Sorta. But not for long. (found that one out on a long-previous build)
Okay. so I replaced the really black plugs late last night and fiddled with the coil wiring and it did not start. Looked at it again this morning and it did not start. Realized I messed up on the coil wiring I did last night (probably too fuzzy headed at midnite) and fixed that and it started right up. Took it for the aforementioned four house spin and indeed breaking up under heavier throttle again. Must be running very rich with the very black plugs I took out so I'm going to fiddle with the mixture on the carbs. Please understand that I am new to flatheads and EXTREMELY unschooled when it comes to these 94 carbs. I never ran a two barrel like these and especially two of them on the same engine. Does anybody have a tried and true method to adjust the mixture properly? The carbs feed to a single plenum so I don't think the sit on top of the carb balancer with the floating ball (forgot the name of the damn thing...I must be getting old) will work. I have tried it before and it really does not change from one carb to the next upon adjustment. Do you use a vacuum gauge in the manifold (there's and extra port there for vacuum if need be)? BTW, I also sprayed some ether around the carb bases and the vacuum ports on the manifold and there was no change whatsoever with the engine running so vacuum leak has been ruled out as well. Andy
Check your power valves for leaking....new P.V.'s will not seat correctly in 94's without some re-work...
Single plenum...adjust by mixture and speed entirely. With engine idling turn mix screws in slowly, seeking the lean end of proper running. Check RPM or continue by ear...basically stock engine, probably should idle around 400 but maybe keep it up around 5 until you are sure all is happy. Test lowering idle speed with that screw, if you go lowere go around and adjust all 4 mix screws again. Go by smoothness and perceived happiness of the engine. After you have found lowest and leanest point, turn screws to very slightly richer and consider it done. If anything goes strange on you, block off one carb, get other happy, then swap. Two separately set carbs will then idle a bit high when paired up again but you know what to do about that. NOTE that idle fiddling around is done with linkage loosened! You get your idle right, then affix linkage to work from that point!
I was struggling with the exact same issue with my 21 stud for the last few weeks. I replaced/checked everything, including new carbs, jets, coil, condenser fuel pumps, wires, sparkplugs etc. Mine would idle great and rev up in the garage great and then break up under a hard load while on a drive. I finally pulled the distributor a second time for further inspection. My dizzy had an adaptor to replace the original coil on top of the dizzy with a modern coil. When this adaptor is installed, there is a stud for the small coil wire that goes through the adaptor and connect to a cone-shaped spring that energizes the points. On my car, this stud was loose and allowed the spring to wobble and lose contact with the points at certain times. I tightened the stud and all is right with the world.... You might want to take a look at that area.
This!!! And what PV's are in your carbs? IIRC I ran only one on my 276 Merc with dual 94's with straight linkage.
This is a good and easy thing to check! On my buddies 8ba, he had a new Mallory dual point distributor and the points plate was loose... wreaking all kinds of havoc in the higher rpm band as the plate/points would wobble around. I bet MikeW is onto something... I will agree w/ leaky power valves creating similar issues. Quick and easy to check. You really should be VERY familiar with a 94 if you're going to run 2 all of the time! They're pretty damn simple carbs and there's a ton of tech on them here on the HAMB! 3blap.
Thanks all. Will try Bruce's carb adjustment procedure and remove and check dizzy within the next few days and get back onto the thread about results. Won't have time to fiddle with it till probably the weekend. Gonna be a busy couple of days here in Mayberry. I have rats to race and bacon to bring. Andy
Andy, ^^^^^^^ Just remember even if you win the rat race you're still a rat! [emoji37][emoji23] JK of course
Hopefully not too late to the party, but take a look at your ground wire. My late model truck had similar symptoms, and the ground wire is a cheap fix!!! It is very possible that you pulled it when you swapped out the trans.
Had a similar problem with our flat powered roadster (see video below). Set out on annual local reliability run - 100 miles +/-. About half way out it had an occasional dead miss at highway speed. After the run, was headed home and the miss became worse. Finally somewhere in down town OK City, in a light rain, it crapped out and I coasted to a side street. Right across the street from the big Bauhaus inspired Mercedes dealer! Went over to use the facilities. Snooty bastards! Went back out in the drizzle and fiddled with it for some time. Took the carb top off to check, etc. It would start, run for a few seconds and die. Maybe electrical? Coil wire had a break in it just at the connector where it bolts to the coil. The insulation looked fine - but inside the strands were mostly broken! OOPS! By now, you've likely checked all connections? Keep us posted.....
Yup, the wiring is brandy new. Just finished wiring it last week and it ran flawlessly until this crap started going on. I've checked the wiring a buncha, buncha times and it all looks real good, even pulled hard on the connectors to see if they would come apart.. All good. I'm hanging my hat on it being way too rich a fuel mixture or maybe the points came out of adjustment. I'm going to pull the crab dizzy and check the points setting and then adjust the carb mixture as per Bruce Lancasters suggestion. Will keep all posted so when this happens to YOU, you don't pull out your hair like me. Ground wires and straps are all good by the way. Andy
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