Viola: New Everything

Repeated the same coil test but with the new coil with the proper 89mm mounting points.

So this test had all the new stuff:
- Japanese ignition coil (is it really Mitsubishi?)
- Nippondenso condenser
- Nippondenso points
- NGK plug boot
- brand new NGK spark plug

Viola: Big Fat Spark!

Finally figured out the problem with the electrical setup - and managed to get spark!

The problem turned out to be that the mounting bolt on this Chinese coil was actually grounding it to the frame!

After an afternoon of testing, I found a big clue in that I was only seeing 0.3 volts between the open points (where there should have been at least 6).  Folks on the S90 group confirmed that something was shorting.  I started to work backwards from the points, checking each connection, but got all the way back to the coil and was still seeing the voltage drop.  Finally realized that it was the coil mount, and confirmed that when I found continuity between the bolt and the wires.

So I hung the coil from the frame so it wasn't touching anything.  With that done, I was getting 6v at the points.  And with that, I got spark!

For reference, here's how everything was wired.

Condenser
- long green wire connects out to points
- short blue wire to the coil

Coil
- green wire to the condenser
- black wire to battery positive
- spark plug body ground to engine block

Battery
- positive lead to coil's black power wire
- negative ground to engine block


Also, these were the components:
- the NGK plug
- the Daiichi points and condenser
- the #1 chinese coil

The final setup that worked.

Daiichi points and condenser.

DON'T leave the points connected with the battery wired up.  It will overheat the coil and crack the plastic.

Old (bottom) and new points.  These appear to be Nippondenso style points.

New points mounted.

And finally some new old parts from eBay.  A points cover, baseplate and head cover for Viola so that I can clean hers up and use them for the model top end.

Viola: Still No Spark

Tried the same test today but with the new condenser.  Still no spark.  So I started testing with the multimeter.

Found there was NO continuity between the HT spark plug wire and the coil ground wire.  So definitely seems like a bad coil.  Ironic since it's new, but perhaps somewhat expected given the Chinese manufacturing...?

Expecting a new coil from eBay soon.  This one has the correct mounting tabs, so hopefully it'll do the trick.

Also gave the new NGK boot a try, just in case that was part of the problem.

Viola: No Spark Today

So... this didn't work.  Not really surprised.

I've got a new condenser now, so I'll try it again with that.  Plus I'll put the head cover back on and set static timing.

Viola: Air Hose Measurements

The S90 carb-to-air box hose should be 1-3/8" (a bit smaller than the CM91).  Hoping I can find the same blue hose at the hardware store just in the slightly smaller size.

Viola: One Good Carb

Prepping the K1 carb to test it on Viola's running engine.  Found the K1's valve pin to be sticking, so I replaced it with the one from the "B" carb.  Had to reset the float height afterwards (19.5), but with that done, she seemed to be in good working order with no leaks.

For reference: the K1 now has B's float valve and seat but kept the better gasket.  Thus B now has K1's seat and valve (but same old gasket).