Howdy boys, got a troubleshooting question for you: A couple times my 46 MERC truck, with a 53 Flathead engine, would buck like a rabid horse, then die. Usually it would start back up and be fine. I cleaned all the connections at the solenoid, battery, looked at all the connections to coil and dizzy and everything seems OK. Then it started and ran fine for the last couple trips so I thought that was it. Today, after warming it up and driving fine for about 10 minutes, it did it again - bucked like mule and then died. I coasted into a parking lot and went over every wire, plus the fuel system. I found a bit of a loose conxn on the generator, and a ton of corrosion in the centre (coil) hole on the dizzy cap. I cleaned it out really well, as well as the coil lead. It started right up after and I ran awhile it before taking off again. Ran great and I thought I fixed it - again.... 500 feet up the road it happened again and died. This time I left it and caught a ride home from another gear head. I'm pretty sure it's not fuel - the bowl is full and when it runs, it runs good, so fuel is making it to the carb. Plus the "bucking" to me means loss of electrical. My only guess now is it's losing power to the coil.....but why and where? I don't know much about the regulator or generator on these, so not sure where else to look. Any help is appreciated!!
How old is the coil? May be a wild shot, but the "bucking" makes me think intermittant ignition problem. good luck!!
When was the last time you tuned it up? A corroded cap tells me you are over due. Tune ups in the 50s were every 10000 miles including cap and wires. We seem to forget that with our modern cars. The plug wires are probably just as bad. You have to start there with the basics. That might not miraculously fix your problem but it still needs to be done before you go on a wild goose chase.
I would lean towards a tune-up. Points Condensor,cap, rotor, and possibly a new coil ...bad condensors & bad coils have a tendancy to crap out when they heat up...JMO Jim
sounds like a vapor lock to me its sucking air somewhere gas tank vent wrong gas cap these things are known for this
I'll bet my money on the coil. I just had the same problem with my model "A" banger. It started with ocational missing and bucking at 45MPH,then it would shut off completly. The car would restart,and go about 1/4 mile then die again. After changing to an antique Mallory 6V coil,everything is fine now.
In old ford tractors and points engines an excessive amount of loose rust will cause the engine to misfire and buck like that. THe dust gets spinning inside of the cap. I would look for a larger piece of dust or debris in the stributer housing
I get called out every spring to start swathers and balers for friends, the gas these days ,SUCKS . BUT, I would also lean toward the bad coil , possibly condenser, Here is a cheap gamble . $1.49 for a can of HEET POUR THIS DIRECTLY into the vent tube , in the throat of your carb, (the tube looks like a straw cut at an angle ) be careful to pour a small stream ONLY into the vent tube ,not down the carb into the engine,, til you see the accelerator pump rod get a fuel ooze around it ,pour the rest of the HEET into the tank,,, let it sit for 15 minutes , start it up , (it's gonna run a little rough for a bit, til the float level evens out ) This will evaporate water in the bowl and other condensation in tank and lines, ,, If you do not have the vent tube , 5 screws hold the top on your carb , and removal will allow a visual inspection of the float bowl. If the problem is still there , you've eliminated bad fuel as a possibility , for a buck and a half , and it can't hurt a thing ,, I'd , Again , look toward tune up parts tho' coils go bad ! Hell I had the buckin' and die ing problem on an early GM HEI system . after the guy had done a tune up, everything looked good , idled great til you gave it gas , I went through everything , pulled the cap , looked good , then I accidentally,manually, moved the vacuum advance , and the plug on the ignition module pulled away , wasn't plugged in, it was just sitting on top. So when it accelerated the advance pulled the contact away Hell I even saw a dead mouse that must have got in the points door in a gm distributor Hope you win , Joe
May not hurt to lay a hand on the coil when it does as well. If it is hotter than a 2 dollar pistol your coil may be soaking up heat or be on its way out. I would assume that if you have had the old mule on the road for any amount of time that heat soak is notgoing to eb the problem and that getting ready to go to the big parts shelf in the sky is more likely. Tommy is probably the closest to correct here, but the coil is another place to look.
Another vote for coil. Gets hot. bucks and quits. You mess around under the hood, the whole time the coil is cooling. You start it after it cools it runs for a little bit then bam, your roadside again. A rewire and clean connections are a good idea, as said.
Thanks to all you boys for helping me out. All replies seem to point to one of the above, so I'll be going at it today - before I get "bucked" clean off!
Had a condenser do a similar thing. Would cut out whenever it got warm. Also check distributor cap for hairline cracks and everything else said earlier. Good luck!
about a year ago, while driving down the highway, the ignition coil on my '62 would cut out intermittently, causing a "bucking" like i'm sure you are describing. i changed the coil and never had the problem again
I would also check ign wiring. I had faulty wiring(from prev owner) and when I got goin on the freeway the combo of my side pipe vibration and shitty wires it would cut in and out. Hope you get er goin soon.
Just to update this thread - finally got to fixin' the Merc over the long weekend. Put all new plug wires, coil and ignition parts in it, pulled the carb off and gave it a blow-job. Runs like a champ now (wouldn't you? LOL!) Here it is starting easy (for a 6V!) and running fine: http://youtu.be/nC0eTy4xtEk Time to get back to work!
Some thing to think about. I had a similar problem with my 29 4 banger. Found a bad coil. Got a new one From NAPA. All went bad with in 2 months and they gave me replacements. Finally called Bubbas in Indy. His was twice as much, BUT he said his would be the last coil I would need. So far he right. The NAPA coils ran HOT, his runs cool and no more problems. Iceman
Well , looks like his problem is solved now, in as much as the entire ign system has been pretty much replaced. However, I have a feeling that the origional problem was nothing more that the conderser. A bad condensor was so common in the 50's that most everybody that drove knew pretty much instantly what was the problem when a car acted as described. I was amazed that this thread went on seemingly forever before anyone even mentioned a condensor -- I guess that with electronic ign. being the standard now for most of the last 40 plus years, it would take an "old duffer" ( like me) to remember.
Glad it's fixed.... Ran into something similar years ago. Dirt daubers had made a home in the gas tank vent!!
The Jalopy Journal
