Pulse Pack?

[joho09]

Greetings all, I've been having a problem with my 1971 125. In the past when we are underway, at planing speed it would momentarily stall then as quick as it stalled it would pick up and run fine. It might do this a couple of times or not at all. This weekend I brought it in the shop and I am not getting fire at the plugs. I have 12.54 dc volts at terminals # 8 & # 9 but when I do the power pack test where you ground the black lead of the tester and connect the red lead to terminal # 5 and crank the engine I get a reading of 0. would this indicate a failed power pack? If not any other suggestions? Thanks, Joho09

 

[F_R]

Re: Pulse Pack?

What kind of tester are you using to test the pulse pack output at terminal 5? Inappropriate testers won't show anything there. It is a very quick, high voltage pulse. If it truly is no output on terminal 5 the pulse pack is suspect, but don't ignore the sensor circuit. And make sure you still have the 12v at 8/9 while cranking. Could just be the key switch or something.

 

[joho09]

Re: Pulse Pack?

I am using Model DM-1400A digital multimeter made by A.W. Sperry Instruments for that test. It may not be sufficient . I checked the voltage while cranking and it was 9.41 volts.

 

[joho09]

Re: Pulse Pack?

Perhaps I should check out the key switch, It is original equipment to my knowlege. Thanks

 

[F_R]

Re: Pulse Pack?

All we had back in those days were the stevens neon tester, but nowadays they use peak-reading voltmeters (I don't have one). I would think the pulse would be over before your digital multimeter can react.

Key switch is probably ok since you have 9.4v at cranking, but that sounds kind of low. How's the battery and connections?

 

[joho09]

Re: Pulse Pack?

Well, I removed the switch from its housing and looked at it. After moving it around and examining it, I checked for spark and had it. I am going to replace it and hopefully that will solve my problem. You guys are great and I thank you for your wise input!!