Thread: Stuee's 101 Rebuild

One other thing I am thinking is if the O rings around the main jet were leaking due to age , I wonder what the carby diaphrams are like.
Use a phillips head screw driver and remove the cover on the top of the carby helded with 4 screws.
Check the condition of the diaphram (looking for holes or a tear) and ensure the big alloy piston slides nicely up and down ,being carefully not the hurt the main jet needle in its main jet hole.
Add a couple of drops of engine oil in the damper for the carbys which is the black knob thing in the top cover of the carbys.
(lack of oil in the small damper piston causes a flat spot under accelleration )

Originally Posted by 101 Ron

The spark just needs to be fat and blue while cranking.

This is what I've been hoping for but so far only had a sissy little one.

In terms of setting it up, its only quite basic, so provided all the parts are fine, I must be missing something obvious.

I've set it up as per the instructions (below) and the electronic ignition side is firing when its supposed to, just its very weak. The only difference is that I have wired up an additional 12V supply through a relay that powers the coil directly when cranking over. Using a Bosch GT40R which has approx 1.2Ohms across the primary contacts, and the ballast resistor has a total of about 1.8Ohms. But on a 12V source this would only give the coil 4.8V.



There is the possibility the ballast resistor is not suitable for the GT40R (don't know if they come in a wide variety of resistances??), but the two were sold to me as a compatible pair (GT40 being for use with no ballast resistor).

Aerostart has been used quite a bit today and didn't really get any extra cylinders firing. Which I gather from what you say points me back to the ignition.

Just checked the diaphragms and they are still good. If I had a car trailer I probably would have dropped it off to the local workshop by now, but I'm stuck with it. Will ask a few of the WA guys I know if they are free in the next month or so to come take a look.

The GT-40 and GT-40R coils are great coils.

If you are using a 12V system, the GT-40 works with full voltage applied. The + terminal has 12v supply attached, usually from the ignition switch. Sometimes this switch develops dirty contacts so sometimes I wire a relay operated by the ignition switch so any ignition devices are operated almost directly from the battery.
The - terminal goes to the points or other triggering device.

The GT-40R operates on reduced voltage. The resistor reduces the voltage. A relay operated from the start signal shorts out the resistor thus applying full voltage to the coil.
This is done because, during starting, the battery voltage drops and it ensures the best possible spark is produced during starting.

If I have troubles with ignition to start a motor, I ensure all possible sources of voltage drop are removed. I wire the coil directly to the battery (via a fuse of course) and check there is a good earth connection from the engine block to the battery via the chassis.

Apart from the earth lead on the starter motor, are there any other earth points between the engine block and chassis?

Whats the spark like coming straight out of the coil while cranking and using another sparkplug and a spare lead......remember to earth the sparkplug
.
With the Neg wire off the coil from the ignitor,,ie removed, install another temperary wire , turn on the igniton and flash the end of that wire to earth,
You should get a spark coming out of the coil on the spare lead and sparkplug you have rigged up.
(you may get a small jolt from that wire you are flashing to earth)

I cannot remember where the earth lead is on the 101.
most vehicles have a heavy battery type cable running from one of the starter mounting bolts to the chassis and the Neg on the battery should run to the chassis/ or to the mounting bolt on the starter.

As Ron says, test the spark.
An extra earth strap could help.

Originally Posted by 101 Ron

Whats the spark like coming straight out of the coil while cranking and using another sparkplug and a spare lead......remember to earth the sparkplug
.
With the Neg wire off the coil from the ignitor,,ie removed, install another temperary wire , turn on the igniton and flash the end of that wire to earth,
You should get a spark coming out of the coil on the spare lead and sparkplug you have rigged up.
(you may get a small jolt from that wire you are flashing to earth)

Ok I've just tried this (earthing plug and coil to the engine block) and am not getting very much spark at all, if anything the spark between the coil negative and block is bigger. So I take it from that, that I have either a shot coil or poor power and earth connections, the old coil is behaving in much the same way, either that or my interpretation of spark size is skewed.

Have cleaned up all the plugs to start cranking again tomorrow, but will also look at putting bigger power and earth wires to the coil as well.