'75 merc 1150 ignition box test

[monk-monk]

I need info or a Link as to how to test my ignition box...it goes something like, red wire should have voltage with key off, and when you turn the key on there should be voltage on the white wire...just got my powerhead changed and i have no spark at the coil wire to the distributor...its either the switch box or the coil and i need the test procedures for both..Thanks!

 

[monk-monk]

Re: '75 merc 1150 ignition box test

Update...I have 12 volts at the red wire with key off...i have 12 volts on the white wire when the key is turned on...what and how do i test from here...?

 

[monk-monk]

Re: '75 merc 1150 ignition box test

So if the voltage on the red wire and the white wire is correct, and i jump the brown and white posts on the dist side and with key on, when i ground the black post i should get spark...if i get spark the box is ok and the trigger is most liely the culprit? and no spark from the black would indicate a bad switch box?...is this correct..?

 

[Laddies]

Re: '75 merc 1150 ignition box test

 

[monk-monk]

Re: '75 merc 1150 ignition box test

Thanks Laddies...i noticed at the very beginning it stated about a spark gap tester and a trigger tester...i have neither, im interested in those tools, but at this point i know im getting no spark out of the coil to the high tension lead...the trigger tester might be of some help at this point but again, i know i have no spark so the spark gap tester really wouldn't help right now...I will check the voltage on the brown trigger wire as stated...what is DVA voltage..?...I will also do the grounding of the black lead with the rotor on #1...

 

[Moody Blue]

Re: '75 merc 1150 ignition box test

BEFORE you connect wires together and jumper things to ground, make sure you disconnect the trigger circuit (wires from distributor) first or you will be needing a new trigger.

 

[monk-monk]

Re: '75 merc 1150 ignition box test

Oh yes, im aware of that moody...heck, i don't even like the idea of tapping that black terminal on the dist side of the box to ground...i can't believe there's not an easy way to test these components...gotta have this tool, gotta have that tool...heck, it's easier for me to pull my known good box of my other motor, install another coil and if that don't work than i'll change the dist...i have a bunch of spare parts, guess i'll just start changing the easy stuff first and move forward till i get...it's the box,coil or trigger..simple as that...

 

[Laddies]

Re: '75 merc 1150 ignition box test

Sorry to bothered you two geniuses, one asked for the trigger test so I give it to them and then the other comes on with their brilliance and the two belittle the test. Thats exactly why I seldom post here any more. Thanks Guys

 

[chum1]

Re: '75 merc 1150 ignition box test

Sorry to bothered you two geniuses, one asked for the trigger test so I give it to them and then the other comes on with their brilliance and the two belittle the test. Thats exactly why I seldom post here any more. Thanks Guys

Dont take it personal, others are here to learn too.

 

[monk-monk]

Re: '75 merc 1150 ignition box test

I did not belittle the test..!! Look at what i said just after you posted the test..I said i didn't have the tools to perform the test step for step, but i also said i'd try everything in there that i could...and even said i was interested in those tools...I started this thread and nobody else came in asking more questions...i don't no where you got all that..! I did say i can't believe the testing is not simpler...thats all! I said without the tools its easier for me to just change everything...NEVER BELITTLED THE TEST...PERIOD...!!

 

[Moody Blue]

Re: '75 merc 1150 ignition box test

Sorry to bothered you two geniuses, one asked for the trigger test so I give it to them and then the other comes on with their brilliance and the two belittle the test. Thats exactly why I seldom post here any more. Thanks Guys

Holy crap Laddies, take it easy. You comments are way out of line, offensive and unwarranted. If that's the kind of "help" you are offering then it won't be missed by me.

The ONLY thing I mentioned was a cautionary note on performing the switchbox test in relation to THIS post

So if the voltage on the red wire and the white wire is correct, and i jump the brown and white posts on the dist side and with key on, when i ground the black post i should get spark...if i get spark the box is ok and the trigger is most liely the culprit? and no spark from the black would indicate a bad switch box?...is this correct..?

Re-read my post. It did not have anything to do with what you posted. I did not belittle anything. Simply trying to help out a fellow boater. Is that not the purpose of these forums?

 

[monk-monk]

Re: '75 merc 1150 ignition box test

I got it running...it was the switch box...i performed the test of the switch box on the dist side...got no spark at all when i grounded the black post...i heard no click out of the coil either when i grounded it, and had no spark from the high tension wire to the dist cap...this test method does work, and it's a lot simpler than i thought...i've learned something in the process, my motor is running good..and im happy...

 

[Moody Blue]

Re: '75 merc 1150 ignition box test

That's good news. It's handy to keep a parts motor around for those old-timers. I've got two donors for my '71 Merc 800.