no fire to plugs on '55 640

GeneG · Jul 10, 2014

OK Guys here's the scoop. I was moving dirt with my 640 when it juat died. It had been missing a little but I have an issue with tank rust and so wasnt concerned.
So far I gapped the points, repalced coil, rotor, points and condencer and still have no spark to plugs. The spark from both coils seem weak to me, not blue as I expected (more yellow). even ran wire direct from battery to coil and didn't get blue fire. Even removed and cleaned carb in off chance that it was too dirty.

I have current to points but not to plugs.....What in heck am I missing?

Thanks all,
Gene

Royse · Jul 10, 2014

Do you have battery voltage to the points when open?
Often the insulator that goes through the side of the distributor
cracks and grounds, or partially grounds, the wire from the coil.
You can remove the insulator and run a straight wire from the
points to the coil as a test, just make sure it doesn't hit anything.

old · Jul 10, 2014

First off you threw parts at it before trouble shooting the problem. New points some times need to be clean to work as they should. Gap should be 0.025. You should have a spark at the point when you open them by hand but if you try doing that be careful or you will find spark the hard way. Your spark should also jump at least a 1/4 inch gap. A bad cap and or rotor can also cause that problem so you need to check spark out of the coil wire and also the plug wires

NNP · Jul 11, 2014

like said, with that style distributor, I check that distributor wire pass-thru and copper strip first.
Sooner or later they all short out there.
usually a rust bridge.
Your voltmeter/test light/ohm meter will tell you.
Like Royce said, a wire replacing it will work fine.
Sometimes with a rust bridge or time eroded insulator,
just loosening the pass-thru connection and fitting a u-shaped
piece of rubber in there will 're-insulate' it without a teardown.
(like in a field, miles from the shop

)

souNdguy · Jul 11, 2014

put a test lamp inline with the primary wire to the coil. roll engine over.. lamp should blink.

if no lamp. check power wire.

if it stays on constantly.. check for short at the dizzy pass thru

post back

no fire to plugs on '55 640

GeneG

New User

Royse

Well-known Member

old

Well-known Member

NNP

Member

souNdguy

Well-known Member

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