4.5 mercury still spark intermittant

[GRAMPS]

checked all connections, installed all new wires. has no shut off switch. mercury part # on top of stator is 336-4524 ( thunderbolt) still have no way of knowing year model as serial # 3399968 does not jive with any lists! (how can that be ??) hard to check coil or stator coils without proper ohm info ! HELP ! I'm an old fart but i'm going to get this old merc running if it kills me !

 

[Laddies]

Re: 4.5 mercury still spark intermittant

First your engine is a 1972, Here's the test but don't forget the most frequent problem with the pts. CD is the insulator block on the points.

 

[bktheking]

Re: 4.5 mercury still spark intermittant

Is this phase maker?? Green wire coming from the stator to the coil? 1 wire from the points to the other side of the coil? Points on these rarely go bad, disconnect the stator wire, grab a DVA and set your meter to high AC ( 1 wire to ground, the other to the green wire) and pull, you should see 400+ volts. If not the stator is shot. If you have power, then reattach the green wire and disconnect the wire coming from the points on the coil. Connect a spark tester, pull it over and quickly tap that disconnected wire to ground. If you observe spark chances are the insulator block is shot, this is how I troubleshot a 7.5 hp with the same setup, difference being it was a twin.


Ohm out the coil with an ohm meter or multimeter to rule out the coil.

 

[GRAMPS]

Re: 4.5 mercury still spark intermittant

Thank you " Laddies" for that info but I need the "specification readings in Section 9 " if you have them .I may have a bad capacitor and that is probably not available ! I replaced the insulator block quite some time ago ! THANKS FOR ANY HELP YOU CAN GIVE !!

 

[Laddies]

Re: 4.5 mercury still spark intermittant

I only have seen one capacitor bad in about 40 years, think thats why they are NLA, anyway here's the specs you need

 

[Laddies]

Re: 4.5 mercury still spark intermittant

Here's a good test for the diode rectifier

 

[bktheking]

Re: 4.5 mercury still spark intermittant

If it's got a cap it's not the same system i'm thinking of.

 

[Maxz695]

Re: 4.5 mercury still spark intermittant

agree bad dirty points will fire ignition on and then off again