Hot Rod 960 Dies

showcrop

Well-known Member
I have been having an intermittent problem or perhaps a string of different problems with my 960 puller for about a year. I had the engine professionally rebuilt about ten years ago, and it has for the most part run very well since. The first time it stumbled and died was about a year ago, it was a series of worse and worse misses until I had to push the clutch in. Cleaning the filter bowl seemed to take care of it, but a few weeks later on Labor day last year it was worse. This time we found a carbon track on the rotor indicating that it was jumping to ground on the shaft. I replaced rotor, cap, wires and autolite plugs. It seemed to be better, then it started missing again. I went into the fuel side again and tested for flow and found it to be very good from the tank into the carb bowl. I opened the carb and found it to be very clean, and found all passages clean, but the float was 1/4 inch low, so I took care of that and tested it on the Dyno. On the Dyno it would make and hold full power for ten minutes. Next time on the track, yesterday, I got half way down the track and it skipped twice and died. It did exactly the same on two hooks. Last night I went at it again, checking everything in the dist. (EI), including advance, wiring, I even dumped the gas from the tank to check for something floating but there was nothing. I checked for an intermittent ignition switch and struck gold here. I ran wires out to twist together to take the place of the switch. I thought for sure that I had it, but today it did exactly the same thing; two misses then dies, but pushing the clutch in catches it. Any ideas?
 
(quoted from post at 00:23:04 07/27/15) I have been having an intermittent problem or perhaps a string of different problems with my 960 puller for about a year. I had the engine professionally rebuilt about ten years ago, and it has for the most part run very well since. The first time it stumbled and died was about a year ago, it was a series of worse and worse misses until I had to push the clutch in. Cleaning the filter bowl seemed to take care of it, but a few weeks later on Labor day last year it was worse. This time we found a carbon track on the rotor indicating that it was jumping to ground on the shaft. I replaced rotor, cap, wires and autolite plugs. It seemed to be better, then it started missing again. I went into the fuel side again and tested for flow and found it to be very good from the tank into the carb bowl. I opened the carb and found it to be very clean, and found all passages clean, but the float was 1/4 inch low, so I took care of that and tested it on the Dyno. On the Dyno it would make and hold full power for ten minutes. Next time on the track, yesterday, I got half way down the track and it skipped twice and died. It did exactly the same on two hooks. Last night I went at it again, checking everything in the dist. (EI), including advance, wiring, I even dumped the gas from the tank to check for something floating but there was nothing. I checked for an intermittent ignition switch and struck gold here. I ran wires out to twist together to take the place of the switch. I thought for sure that I had it, but today it did exactly the same thing; two misses then dies, but pushing the clutch in catches it. Any ideas?
ou found it! Keep the clutch in.
 
Lol, it won't pull well with the clutch pressed . Where is
your battery grounded ? Is the fuel tank venting ?
 
(quoted from post at 19:16:51 07/26/15) Lol, it won't pull well with the clutch pressed . Where is
your battery grounded ? Is the fuel tank venting ?

battery is grounded to original position. Tank vent is positive. it has 12V with 6V starter so it usually starts with less than one revolution. After posting yesterday I unloaded and the battery was dead, so after a good charge I will take it in and get it load tested. It is my top suspicion at the moment. it may be twelve years old and not taking a full charge.
 
I know you've checked it, but an engine that pulls forever on a dyno or in the shop which behaves erratically in use,
usually points to a float/needle issue.
As the tractor tips, or rocks back and forth, a float with a sloppy pin or float lobes not perfectly square/balanced can make contact with the bowl.
Some carbs with a proper though high float level can overflow
when at a steep angle..giving a miss or cough.
With the front airborne,if it coughs, when you clutch it to save it, watch the exhaust pipe for the puff of black smoke when it clears itself.

I have a couple zeniths that will cough coming down a steep hill, or when I don't see a big rock and I bounce the front.
 

I can't fault your trouble shooting but would offer a comment. I had a similar problem with a motorcycle - it would break up under load...sometimes. I noticed the tach needle would drop to zero when ever it happen and concluded it was ignition. I did the normal checks, found nothing wrong, replaced the spark plug, plug wire, then the coil, then the ignition box. I finally replaced the ignition sensor and the problem went away. The sensor tested good and after it was removed I placed in the oven and tested it hot, then the freezer and tested it cold all tests showed a good sensor. To this day I do not understand how the sensor was affected by engine load.

I would suggest changing the EI if you have not already done so. Also a tach that drops to zero when the spark goes away is a useful tool to sort out the ignition versus fuel question.
 
Does it have the stock carb and fuel lines? On your dyno pulls do you load it the entire time or cycle up and down?
I have had mine run fine under load for about 100' then starve for fuel when I forget to turn on the fuel pump (dummy!)
you may want to try a small electric fuel pump and see if that fixes your problem.
 




has to do with bouncing... could be float too high and flooding, or could be electrical.... I have seen both. A car that every time I jumped on the bumper it would stumble... float was too high and it flooded... pickup that had a bad primary wire to coil that would cut out everytime it hit a bump... Good luck..
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top