Trigger test for '72 80hp Mercury

[flstanleyii]

I have a '72 80hp, 4 cylinder Merc (serial # 3312746) that has no spark to any of the plugs. With the help of this forum, I believe I've isolated the problem to a bad trigger. At Laddies suggestion, in his post to Bryan22 on June 16, 2005, I disconnected the mercury switch, placed the engine at TDC, disconnected the distributor side terminals, jumped the brown and white posts on the 3 terminal side of the switch box and arced the black post to ground. With the switch turned on, I do have fire, which indicates a bad trigger. As parts are hard to find for this year of engine, I'd like to replace the entire distributor, if I can, but of course that means going to used parts. Prior to spending a lot of time and money on a "pig-in-a-poke", is there anyway to test a trigger with the distributor out of the engine? I have a couple of leads on used distributors but they've already been removed. I've checked the forum archives for some kind of a test, but have had no luck. As this is my first posting to this group, perhaps someone could point me in the right direction within the forum or perhaps knows of a way to test a used trigger if the topic hasn't been covered before?? As always, any and all comments would be greatly appreciated!!<br /><br />Thanks in advance!!<br /><br />Frank

 

[Laddies]

Re: Trigger test for '72 80hp Mercury

With the trigger wires hooked up crank the engine with the starter, you must have 9 1/2 volts on the white post with the starter turning the engine, ck the brown trigger wire 9 volts min., ck between the blk and the white wires with a DVA you should have 3 volts, low voltage between them means a bad trigger--Bob

 

[flstanleyii]

Re: Trigger test for '72 80hp Mercury

Thanks, Bob!!<br /><br />I have an extra pair of hands coming by and when they get here, I'll give that a try. However, if worse comes to worse and it is the trigger, any way to test one that's been removed from the engine??<br /><br />Thanks again!!<br /><br />Frank

 

[Laddies]

Re: Trigger test for '72 80hp Mercury

Sure just hook up the wires and turn the dist. by hand, you can't ck for starter load however and remember to stay away from the high tension lead

 

[timmathis]

Re: Trigger test for '72 80hp Mercury

Yas that is right if your trigger has A roter on it. If not you can test it with A feeler guage.