22 replies to this topic

[Anthony]

Yep we found the 'default' settings in the su manual that came with the rebuild kit! A classic case of not reading the destructions! Sorry for wasting your time.

Yep I have points and they are gapped correctly. One thing that is puzzling me is which system I have, ballast/non-ballast? By the manual I should have a ballast system. However when I check the supply at the + it reads 12v. I have read on calvers website that if 12v is supplied then it is a non-ballast system. Also my coil which is ducellier says 12v on it. Im confused. The non-ballast system was supposedly updated to ballasted in 1984. The resistance across the ducellier coil is 1.3ohms. Calver states that if a ballast coil is used on a non-ballast system it will spark but the spark will be weak. This seams to fit my situation.

Any thoughts?

Ant.

[dklawson]

Coil operating voltage has to be measured in a very specific way. You cannot just stick a meter on coil (+) and switch on the ignition.

There MUST be current flowing through any ballast resistor (or resistor wire) to produce the voltage drop the coil sees. Repeat your test as follows.
Remove the distributor cap.
Connect your meter between coil (+) and a bare metal earthing spot on the engine.
Switch on the ignition.
Place a screwdriver tip between the points to insure that they are closed.
Read the meter.
12V = regular ignition system, 6V to 9V = ballast ignition system.

With the screwdriver inserted between the points you're insuring that current is flowing through the system. The reading you get on coil (+) will now reflect any voltage drop created by a ballast resistor or resistor wire. If you remove the screwdriver (and the points are open) the voltage will immediately jump "up" to battery voltage regardless of whether your ignition system is regular or a ballast type.

Sorry, once you said "Ducellier" I have to bow out. I've never seen those components.

However, what Calver is mentioning is: If you use a regular (non-ballast) coil on a ballast ignition system, you will have a weak spark (low operating voltage and limited current). If, however, you put a ballast coil on a regular ignition system, too much current is flowing and you will quickly burn up the points and the coil.

[Anthony]

Thanks Doug ill do that. Im lost when it comes to electrics!

[Anthony]

Doug,

Have checked the coil and can confirm it is a ballasted system. I now have a spark.

We adjusted the carb to the default position and got it to run but only with slight throttle. What technique do you use to initially set up the carb? I have an exhaust gas analyser and a colourtune incase you use those.

Thanks,

Ant.

[dklawson]

I have a ColorTune but I never could get it to work properly with dual carbs. I WISH I had a CO meter like you do.

I simply follow the Haynes and SU manual instructions on setting the mixture. Setting up carbs is my weakest area. I don't have the manual in front of me but it's basically making adjustments (typically down/rich) from the nominal start height of the jet with periodic checks made by using the lift-pin on the side of the carb. The idea is that you just barely lift the vacuum piston with the lift pin (perhaps 1/32") while monitoring the engine RPM. (Push the pin up GENTLY until you feel it contact the bottom of the vacuum piston... then just a tiny bit more). If the engine stumbles and nearly dies your mixture is too lean. If the engine RPM increases a lot, it's too rich. If the engine RPM moves up perhaps 50 to 100 RPM and remains stable your mix is close to right. You're also supposed to monitor the exhaust note when you think the mixture is right. It should have an even drone or purr without a lot of "pffft, pffft, pffft" sounds or hunting.

Hopefully someone will respond with instruction on using the gas analyzer you've got. That should give you the optimum mix. If you have to pass emissions tests, it will give better results than the lift-pin method.

EDIT: So what was up with the spark? What brought the spark back?

Edited by dklawson, 08 April 2008 - 01:23 AM.

[Anthony]

I rekon the spark was lost due to a poor connection at the king lead, all is well now though!

Attempting to tune it tonight. Will report back with results.

Just for your info. the HS4 waxstat doesn't have a lift pin.

[Anthony]

Got it running well! Thanks very much Doug for your help, greatly appreciated!

Ant.

[dklawson]

That's great news Anthony! Thanks also for letting me know the HS4 waxstat carbs don't have the lifting pin. I thought all the HS series carbs had them.