Backfiring

J

jwinterstein

Junior Member
Last evening my 29 model A Sport Coupe was running well after I changed the water pump which had a bad front bearing. Today, I left to get gas and about 1/4 mile from the house it began to backfire significantly and lose power and eventually stopped altogether (about a mile down the road). I towed it back and it has adequate fuel which is getting to the carburetor. I pulled #1 plug and turned the engine over and saw a good spark. Points are at 18 and the distributor has the condenser on the upper plate. It will not fire at all at this point. Any ideas?
 
The modern style condensers that mount on the upper plate give a lot of trouble. I would recommend swapping back with the original style points and condenser. There is no advantage with the so called modern set up.
 
Purdy Swoft said:
The modern style condensers that mount on the upper plate give a lot of trouble. I would recommend swapping back with the original style points and condenser. There is no advantage with the so called modern set up.
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I agree.:)

Have you held the coil wire 1/4" from a head nut to check for spark?:confused:
 
Set the points at .020. Also check to see the rubbing block hasn't worn down on the points.
 
Thanks for this Johnbuckley - a little more information - today, with a bit of starter fluid, it fired up. I let it warm up and took it down the road - ran fine. I turned around and when I got into second gear, I stepped on it a bit and then it began to stumble, lose power etc. I pulled the choke and it momentarily started up and then died down and stopped. I popped the clutch and it started again but no amount of gas feed or choke would keep it running. In fact, when I pull the choke, it seems to improve and then as is typical with a pulled choke it begins to die. It SEEMS to be to be a gas issue. I pulled the gas line from the end of a modern filter someone put on before I had it and opened the valve and gas seemed to flow reasonably well. I had also opened the gas cap a bit before going down the road. So, I know gas is getting to the carburetor, and when I pulled #1 plug, I had gas in the cylinder and had spark when I turned it over - so that's where I am at this point. I will read this site and see what I get. Thanks to all. If anyone has any other ideas I am all ears. I will check the points and probably put in a new condenser just on principle.
 
One other thing I have not done yet is check the coil. I do get spark at the plug, but when I think about it, it is not a great zapper! could be under pressure the spark is weak?
 
If you try changing the condenser, get a good one. You'll pay more for the better quality ones from NAPA.
 
Have you checked the filter in the top half of the carb? That filter is usually shot or plugged on the swap meet carbs I picked up years ago. Also make sure the fuel line isn't pushed in too far beyond the ferule or it can block off fuel flow.
 
Ok, I got some things figured out. I followed the recommendation sent by Johnbuckley and the problem - is not electrical. Great coil spark, good condenser, points, plugs carboned but good - gapped them and cleaned them. No frayed wires. I am in the 4% category regarding the reason for an engine stopping - it was fuel. The former owner had put in an in-line filter. I took it off and it was full of rust particles and junk. Then I cleaned the carb which also had some of the same. Put it all back together and it runs like a champ! Thanks to everyone.
 
Hi j,

Some have absolutely no idea concerning the tremendous educational impact on any Forum when someone with a problem is compassionate enough to take the time to type a message reporting how a problem was fixed.

All intelligent educators were humble former students at one time trying their very best to learn.

Thank you for the reply -- it is surely very much appreciated by all who are interested in keeping their Model A's running.
 
I agree with the others ,go back to the original points and condenser. the modern points and condenser is just a head ache.
 
Well good. It just goes to show that most electrical problems are fuel related and most fuel problems are electrical in nature.
I think the newer modern upper plates[within the last 10 years or so] are pretty good, the problem has been fixed. While I too prefer original, the modern plate has been trouble-free as long as the 'good' points/condenser are used.
 
Hi all,

I still have the "modern" points and condenser but I went to NAPA and purchased the Ford 1970 points and condenser for the V8 and also got a new rotor. With the new fuel filter (also from NAPA) and one in reserve, I believe I am pretty good to go. When I first got the car, the first time I drove it for about 4 miles, it overheated. I did have a "loose fan" - someone had not tightened the nut down and I thought it was the front bearing. I put in a new sealed bearing pump (looks just like the original), added a 160 degree thermostat in the top hose (which I changed) and added a bottle of "wetter water" and since then no overheating. If it happens again, it will be a re-core of the radiator.
 
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