1987 110 spark problem

[PAULWI]

I have been having trouble with spark intermittent no start.
1. Assembled a peak voltage tester for stator output (output 197 both sides)
2. Tested output from timer base above.3 volts.
Disconnected black yellow wire still has intermittent spark.
Couple nights ago disconnected wires from output from stator to rectifier tested spark with external spark tester had steady spark on all plugs gap was at least 3/8.
Does this make sense just trying to understand what would be causing the problem with rectifier.

 

[racerone]

If starter is cranking slow you will have spark problems.-----Test starter / battery / battery cables.-----Usual reply to this is that motor is cranking just fine.-----Up to you to do the trouble shooting.

 

[PAULWI]

Motor is cranking great, my question is how does disconnecting leads from stator to rectifier affect spark?

 

[Bosunsmate]

Maybe its grounding out through the rectifier, either a short in the stator circuits or something else i dont know, so i will follow this post with interest.
Perhaps you could test the stator wires and see if there is any continuity between the two seperate circuits, just an ohmn test would do it

 

[oldboat1]

battery charging issues as well? I would just replace the rectifier. (Rectifier is cheap. Stator, not so much.) Believe there were a couple of different stators used, depending on model -- might run that down as well, just to be sure you have the right one. 6 amp for models without t. and t., 3/9 amp for motors with t. and t.

 

[Vic.S]

See the CDI Electronics Troubleshooting guide at https://issuu.com/cdielectronics/doc...ition_troubles Page 40 et seq
Replace rectifier!

 

[PAULWI]

Thanks for the help accomplished continuity ck to ground on both wires from stator to rectifier. I am getting an reading of around 200 ohms I wouldn't think that I should get any reading going to ground. I will replace the rectifier and keep you advised.

 

[Fed]

Retest stator with the yellow wires disconnected from the rectifier, they should be infinity to ground or a very high reading.

For your other question most posters here, myself included, will tell you the ignition is completely separate from the battery charging circuit but in reality the ignition and battery charging coils sit on a common iron core that induces power into the coils as the magnets wizz past past it creating an alternating magnetic flux.
Let's call it a 'flux capacitor' for fun.

My theory is that a short on the battery charging side sucks the guts out of our 'flux capacitor' leaving little or not enough flux to fire the ignition side properly and this is also probably made worse by a slow turning over motor.

I was also scratching my head when I first read the CDI instruction to disconnect the rectifier for further DVA testing.

I think your motor starts on page 43/44.

 

[Bosunsmate]

Thanks for the help accomplished continuity ck to ground on both wires from stator to rectifier. I am getting an reading of around 200 ohms I wouldn't think that I should get any reading going to ground. I will replace the rectifier and keep you advised.

Nope you shouldnt be getting a reading like that to ground, is that from the ignition or the charging coils?
It could be that you have a short in the wiring where the necklace rubs on the side of the crankcase as the timing turns. It might of opened up a short between the coils too.
Did you check for any shorts between the stator coils?

Not sure on FEDs idea, i believe in that as much as i do the Docs flux capacitor being able to take me back to 1955.

 

[Fed]

Just having some fun Bosunsmate, how about if we leave the flux capacitor out and simply say, "Low Voltages due to low initial magnetic flux because of less than optimum cranking speed combined with magnetic flux depletion due to a short circuit on the battery charging side".

Love the subtle difference between It cranks fine & it cranks great.

 

[Bosunsmate]

I really like Back to the Future so I prefer not to leave it out Fed:joyous:
Cant subscribe to your statement yet, although id like too, need this chap to get back with his testing on which of those stator wires was grounding out and also if there was any continuity between them.

 

[PAULWI]

Thanks for all the response. I have had problems for awhile replaced stator and timer base with used units. Was getting same problem intermittent spark sometime one bank then sometime other bank. So I started looking at voltages with a homemade peak voltage tester I made was getting over the required 150 volts ( have to be on DC voltage with this peak tester uses a capactor and resistor to capture the voltage. Now with the stop wire disconnected (black yellow) no change still no spark I had read somewhere about unhooking the wires from rectifier that connect to stator. With the wires from rectifier to stator disconnected cranked engine over with remote switch for starting was getting great spark on all plug had gap of at least 3/8. Update when checking continuity on the wires going to the rectifier realizing that the wires go into diodes I was getting a reading of around 200 ohms each wire to ground leads me to believe that this was grounding the stator so will replace the rectifier.

 

[emdsapmgr]

If you refer to the CDIelectronics.com troubleshooting guide for your engine, the minimum cranking output voltages for the timer base are 0.6 volts-as measured by a DVA. Not what you say you are getting. Also, keep in mind that your engine has to crank at least 250 rpm's in order to fire the ignition system. The timer base voltages do vary, depending on year of engine, but yours should be the 0.6 cranking voltage output.