1978 90hp Mercury Ignition Coil Test

psimonee · #1 December 12th, 2003, 08:00 AM

Trying to troubleshoot ignition problem and need help. I do not have spark. I tried reading with ohms meter the two terminals on the ignition coil. gnd and conv. The result is a closed circuit ( 0 ohms ). Is the coil burnt? Should I have a small reading?

thanks.

simon

mellowyellow · #2 December 12th, 2003, 08:03 AM

swap coils and see if no spark follows.

good luck,

M.Y.

psimonee · #3 December 12th, 2003, 09:29 AM

this motor has a single ignition coil feeding distributor. Sure do wish I had an extra one to swap, but don't.

simon

rickdb1boat · #4 December 12th, 2003, 10:03 AM

Sounds like it's dead shorted out. There was a suggestion to take it to a lawnmower shop and have them test it. Sounds like a good idea to me. You should not be reading zero from all terminals to ground. Betting it's shot!!

This may work, using an Ohmmeter touching each side terminals looking for 0.75 to 0.81 ohm of resistance. Then go from the primary (Spark Terminal) to each small terminal, should read 10,000-11,000 ohms. If not within readings, replace.