spark testing and spark strength testing

pcrussell50

Petty Officer 1st Class
Joined
Sep 21, 2008
Messages
296
my 1959 super seahorse, 35hp, rds21b is running fine right now, but i always want a course of action already doped out in case i run into troubles. this thing has run well since the day i bought it, 9 months ago, and i almost feel as if I'm "cheating" or on "borrowed time" with it because it's 50 years old and i've hardly done anything in the way of maintenance besides install a thermostat, because the previous owner had removed it.

anyway, from reading posts around here, i've been sold on the idea of getting a spark tester, and why not, they're pretty cheap, too?

in shopping around, i've noticed two types:

1]inductive types that sense spark through the insulation, like a timing light
or
2]directly connected types, that you plug inline between the spark plug and the plug wire

as for the inductive type, i already have a timing light. what does the inductive spark tester tell me that my timing light wouldn't?

and finally the big question:

how do you "test" for adequate spark intensity? iow, how do you tell how "bright" and "hot" the spark is?

and if it turns out to be a weak spark, what do you change first?
guessing:
points and condenser first since they are cheap
then
coils, since they are more expensive

thanks
peter
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: spark testing and spark strength testing

I use my inductive timing light under load at all speeds to check the firing. It allows you to look for double firing, heat breakdown, etc. The better models have tachometer readings and can be set for the different engine types.

I use a CDI unit to static test the ignition with the plugs out; that's especially helpful when the engine won't start.
 
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