TheSamba.com :: View topic - Hard starting solved (sort of)-Pertronix and Kadron carbs

Tue Apr 16, 2013 4:08 pm

I have been frustrated with what I considered to be "cold blooded" Kadron carbs I recently bought from the Kaddie Shack. I though the problem was related to the fact Kadrons didn't have chokes.

At the same time I installed the carbs, I also installed an SVDA distributor with Pertronix points that came with the Kadrons.

The cranking time at start up seemed excessive, and oddly, the engine seemed to want to start when I stopped cranking the starter motor. It got me to thinking that maybe the electronic points were not getting enough voltage until the starter motor was released.

I hooked a hot jumper wire directly from the Battery + to the coil and gave it a try.

Boom! instant start and nice cold idle, just like my old Weber ICT's.

I don't know why I am getting such a voltage drop at the coil. My ignition switch is brand new too. Old age seems to take its toll.

I am thinking that maybe I will use the old ignition hot wire to activate a relay which can supply good battery voltage to the coil.

I also removed and replaced the old crimp connectors onto the coil wire connections in hopes a bad crimp was the culprit. I also swapped in another coil but it made no difference.

Any ideas as to why the low voltage?

Tue Apr 16, 2013 4:15 pm

I installed a small relay to shunt Bat V directly to the coil and picked up 1 V at the coil. Thats a huge difference. 3 years and still working fine! :wink:

Tue Apr 16, 2013 4:58 pm

Assuming that in addition to the connectors being replaced, you cleaned the tabs that they slid on to. I would look further upstream. Keep going backwards - like you have the conenction from the coil to I assume the switch. But what do you have on the other side of the switch? Weak voltage feeding it can still cause your issue. See what I mean?

Fix it right instead of putting on bandaids.....

Tue Apr 16, 2013 5:41 pm

Agreed. There are only a half dozen or so connections between the battery and the coil. A little time with a voltmeter will trace it out. Don't forget the ground straps.

Tue Apr 16, 2013 8:48 pm

Thanks for the diagram. I agree that getting the circuit cleaned up is the right approach. I will try that first before I resort to a relay.

But, I have to say, what a difference it made to get full battery voltage on the coil. It totally solved what I thought was a carb problem

Tue Apr 16, 2013 9:54 pm

Years ago I went with a coil that takes an external ballast resister and rigged up a bypass for the external resister during start up. This system was found on many rigs back in the day and gives improved coil output when cold over what the OEM VW system would even with a relay added.

Wed Apr 17, 2013 6:18 am

Even with perfect wiring, there is a voltage drop caused by the long distance involved. The addition of a relay is not as a band aid, but as a performance upgrade. :wink: