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mystery shut off

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redsnapper386

Regular Contributor
hi guys,i have posted in the past on a issue that still persists. i have a 1987 350 a-1,all rebuilt with 80 hours on motor on the hose.the motor runs good for a while ,and will stop running as if i turned off the key switch.what can cause this.i am constantly trouble shooting this.as of today it will not start.it did try,and shut down quickly to day.i think it is electrical some where.is there a way to by pass the wire harnness.also.is it possible that the 50 amp breaker is faulty,and will not release.i have 12 volts at the dizzy.i have good gas with new fuel pump,and 6.5 psi.as i said earlier this keeps occuring.very,very strange.i am out of possibilatys at this point.what can i check next.oh,fuses are good.thanks in advance.lost.:p
 
When it stops do you still have spark?
When it stops do yo have 12v at the + side of t coil?
Looses engine harness plug, it should have a clamp on it. Bad tach will kill spark too,
 
Bt Doctur said:
When it stops do you still have spark?
When it stops do yo have 12v at the + side of t coil?
Looses engine harness plug, it should have a clamp on it. Bad tach will kill spark too,
Click to expand...
yes spark,yes coil, harness tight,will start tach test tomorrow,thanks bt,will post more later.
 
To make trouble shooting easier here is a drawing of what I call a remote starter rig.

You will need these things.

1. One ON/OFF toggle switch

2. One Momentary toggle switch

3. 14-16 gage RED wire about 4-6 feet long
4. 14-16 gage Purple wire about 4-6 feet long
5. 14-16 gage Yellow wire about 4-6 feet long
6. Three alligator clips

The two switches will have one red wire connected to one of the terminals on each switch. Also One of those terminals will have a 4- 6 foot red wire with a Alligator clip on the end

The momentary switch will have the yellow wire connected to the other terminal and the 4-6 foot wire with alligator clip.
The purple wire will go to the last terminal on the ON/OFF switch and have 4-6 feet with an alligator clip.


How to hook it up.

WITH THE ON/OFF SWITCH OFF!!!!!!!!!!!

Connect the red wire to the battery + or the red with purple stripe at the slave solenoid (large top stud).
Connect the yellow wire to the small Yellow with red terminal on the slave solenoid (or to the small terminal on the starter solenoid)

Connect the purple to the + side of the coil

Now while at the motor and the KEY switch OFF, Turn the on/off switch to on this will apply power to the coil + (ignition)

Now flip the momentary switch on and this will engage the starter. As soon as it starts release the momentary switch.

When you are done simply turn the ON/OFF switch off and motor should shut off.

See pic.
 
kghost said:
To make trouble shooting easier here is a drawing of what I call a remote starter rig.

You will need these things.

1. One ON/OFF toggle switch

2. One Momentary toggle switch

3. 14-16 gage RED wire about 4-6 feet long
4. 14-16 gage Purple wire about 4-6 feet long
5. 14-16 gage Yellow wire about 4-6 feet long
6. Three alligator clips

The two switches will have one red wire connected to one of the terminals on each switch. Also One of those terminals will have a 4- 6 foot red wire with a Alligator clip on the end

The momentary switch will have the yellow wire connected to the other terminal and the 4-6 foot wire with alligator clip.
The purple wire will go to the last terminal on the ON/OFF switch and have 4-6 feet with an alligator clip.


How to hook it up.

WITH THE ON/OFF SWITCH OFF!!!!!!!!!!!

Connect the red wire to the battery + or the red with purple stripe at the slave solenoid (large top stud).
Connect the yellow wire to the small Yellow with red terminal on the slave solenoid (or to the small terminal on the starter solenoid)

Connect the purple to the + side of the coil

Now while at the motor and the KEY switch OFF, Turn the on/off switch to on this will apply power to the coil + (ignition)

Now flip the momentary switch on and this will engage the starter. As soon as it starts release the momentary switch.

When you are done simply turn the ON/OFF switch off and motor should shut off.

See pic.
Click to expand...
thanks ghost,thats good info,i will post back when i get this thing running again,i plan on now looking at the balancer its original 28 yrs old and could have slipped on the hub,lots to do now.thanks again.
 
I've seen shift interrupt switches that are on their way out cause this. Try disconnecting it and see if it still happens.
 
Last edited:
That is possibly a good point and we forget the basics sometimes.

One of the first troubleshooting steps in the manuals for ignition problems is to bypass the shift interrupter switch. If you have or suspect an ignition problem

Of course many many years ago the micro switch used was not very dependable and would fail in a closed position.

So if you have your shift linkage out of proper adjustment and you throttle up and the V notch on the shift plate moves this will possibly engage the interrupter switch.


Although if you have spark and it wont start then the switch is not the problem. The interrupter switch will short the ignition to ground.
 
kghost said:
That is possibly a good point and we forget the basics sometimes.

One of the first troubleshooting steps in the manuals for ignition problems is to bypass the shift interrupter switch. If you have or suspect an ignition problem

Of course many many years ago the micro switch used was not very dependable and would fail in a closed position.

So if you have your shift linkage out of proper adjustment and you throttle up and the V notch on the shift plate moves this will possibly engage the interrupter switch.


Although if you have spark and it wont start then the switch is not the problem. The interrupter switch will short the ignition to ground.
Click to expand...
thanks again,i have the newest version of the shift switch which has the pin instead of the roller style.but i can see where it could still stick.will keep checking stuff,so far to date,no luck.weather is slowing me down.
 
That is true with the exception, if the cable adjustment is way out of whack then the shift mechanism will move after shifting into gear as the throttle is applied causing a delayed ignition cutout.
 
kghost said:
That is true with the exception, if the cable adjustment is way out of whack then the shift mechanism will move after shifting into gear as the throttle is applied causing a delayed ignition cutout.
Click to expand...
thanks ghost,also would you send me a drawing on how to by-pass the cut off switch arrangement,if there is a way.
 
The interrupter switch has two wires, One goes to the ignition circuit and the other ground.

So if you disconnect both the wires from the switch or where ever they connect (temporarily) it will remove the switch from the circuit. The shift interrupter does NOT have to be hooked up for the motor to work its only function is to momentarily ground/kill the ignition when shifting out of gear.

Now you may also want to follow the wire lead that goes from the terminal block to the ignition and see if there is a bare section that may be touching a ground.

I am not 100% sure how yours is wired because you have he newer switch. But in 1987 the two wires went to a terminal block. One terminal on the block is the ground wire, the other goes to the ignition.

Follow the yellow brick road to find where they are.

Of course we have no idea if this is your issue. Just one of many possibilities...................

Ya gots to start somewhere.........
 
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