1988 Mercury 90hp 3 cylinder spark

Schnidly

Petty Officer 2nd Class
Joined
Aug 12, 2001
Messages
143
If I hook up a spark tester to my 3 cylinder 90hp mercury outboard and get a great spark at 7/16" gap test does that indicate that my stator, switchbox, coils and rectifier are all working as they should? I figure that all these components lead to spark to the plugs so if I am jumping a 7/16" spark gap all is working as it should? I recently replaced the oem rectifier with a radio shack brand, replaced the switchbox and stator last year and the only items left to replace were the 3 coils themselves. They all checked good and thats why I did not bother throwing money at them. Is it a correct assumption on my part to believe that the electrical system is checking out just fine for firing up the outboard? I also replaced the battery, which was 2.5 years old last week. Bought a marine starting battery which is only hooked up to the starter solenoid. A couple weeks ago my son had the boat out and the starter motor would not shutoff so he disconnected the battery to kill the starter and since that my tachometer, fuel gage, trim and tilt gage and the lights on these gages does not work. The light bulbs on my other gages do not work either, they were burned out. I had one 5 amp fuse under the dash blown too, replaced that also. I just want to be sure that my stator and switchbox are fine and testing for spark and getting a great spark I figure they are fine? Please advise.
 

oldman570

Lieutenant Commander
Joined
Mar 25, 2011
Messages
1,615
The running side of the motor sounds fine. A test of the charging of the battery with a amp meter between the rectifier and the wire to the hot side of the solenoid will tell if that side is working. JMO
Oldman570
 

Schnidly

Petty Officer 2nd Class
Joined
Aug 12, 2001
Messages
143
Thanks oldman, Why can't I just put a volt meter on the starter solenoid where the red wire from the bottom of the rectifier connects to and check it there? Would not voltage tell me its charging? Also, my charging system is a 9 amp system, is that what I should read when hooking the ammeter up in series with those two connections, starter solenoid stud and the red wire going to the battery? Thanks
 
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