no fire

[tippy]

87 merc 25hp. no fire in bottom cyc ,switched coils over and still no spark in bottom cyc.with a good coil? whats next? plugs, wires are good.someone told me maybe bad trigger? what is that and how to fix or check? thanks

 

[newb197]

Assuming all wires are good, clean and connected tight. There are 2 trigger wires, they are the wires going to the positive+ posts on your 2 coils. Try switching these wires around instead. If spark appears on bottom, its the trigger that's faulty. To do an actual test you will need a multi meter to test the trigger leads(2). Trigger leads must possess 100v+ on each of the two wires. To change the trigger you must remove the flywheel then is a cake walk. Hope this may help.

 

[tippy]

thanks very helpful are there 2 triggers or 1 trigger and 2 wires? thanks again

 

[newb197]

there is just 1 trigger assembly with two wires. one brown/white and one brown/yellow. I see them available on ebay (if needed) for $25 and up used and a bit more new. Can see listings here: http://www.ebay.com/sch/i.html?_trksid=p3984.m570.l1313&_nkw=25hp+trigger+&_sacat=0&_from=R40

 

[faztbullet]

Flipping the leads will tell you if its a switchbox as trigger does not attach to coils. The DVA voltage on trigger is 3-9volts the stator output is 25-125 volts on low speed and 100-400volts on high speed

 

[racerone]

The one trigger fires both coils via the switch box.----I would say your switch box is suspect here.

 

[fastjeff]

Correct. The motor would have no spark at all if the trigger coil circuit was open.

I see a few of theses switch boxes on eBay for under a hundred.


Jeff

 

[fastjeff]

..."Have you disabled the kill wire first off. A faulty kill circuit will give you a no fire condition."

Yeah, but on BOTH plugs. Switch box.

Jeff