Erractic firing ignition

[toybuilder039]

1987 200hp Evinrude.
The problem is when checking timing multiple cylinders are showing up at tdc when Hooked to #1 plug wire as in 1 3 and 5. So I also hooked to #2 plug wire and multiple cylinders showed up at tdc as in 2 4 and 6. I have no idea what could be going on I have replaced both power packs and still no change. Thanks in advance for any help

 

[boobie]

How's the motor run ??

 

[toybuilder039]

Horrible. Missing and going on. That's why I indexed the flywheel and noticed the erratic ignition. Compression good. Good spark. But basically each cylinder is firing 3 times per revolution.

 

[boobie]

How about the timer base ??

 

[toybuilder039]

Well I put a ohm meter on it. It all seemed to be good but that electrical stuff is my weakness. I guess I'll pull the flywheel and have a little closer look. Could it possible be stator or rectifier or is that not even a possibility?

 

[boobie]

Shouldn't be the rectifier as that is for the battery charging system. All the stator does is produce power for the packs. Maybe a wiring prob with the stator ??

 

[toybuilder039]

Ok well I'll take flywheel off tommorow so I can take better look.

 

[Fed]

I'd also be looking at stray inputs to the timing light that boobie mentioned on the other thread. (I think).
Even a bad timing light that's 'picking up' things it shouldn't.
You could be chasing a non existent problem with this 'multiple firing' and the real problem is something completely different.

As it stands you're saying that when #1 fires then #3 & #5 are also in front of the pointer

or​

the timing light is lighting when either #1, #3 or #5 fire even though it's only hooked to #1.

It's hard to imagine it even running.

You should have resurrected the old thread to save getting asked all the questions again.

 

[boobie]

Good point Fed !! He should try another timing light as I've has timing lights do that to me.

 

[Bosunsmate]

You should have resurrected the old thread to save getting asked all the questions again.

Yes im not sure at all where things a now:juggle:

 

[toybuilder039]

Well found the problem it was me I'm stupid. I had a spark tester I made I could hook to three cylinders at a time I guess when the other cylinders would fire it would back feed thru #1 plug wire and timing light would pick it up. Went to single tester on #1 all good checked #2 all good. I did get to no my electrical system quite well. I'm going to put new plugs in it already made new wires and see how it runs. Thanks for all your help and sorry for not resurrecting post.

 

[Bosunsmate]

good to get to the bottom of that.
Not sure if you have changed anything to enable it to not run horrible again apart from new sparkplugs.
You could do a drop test on each cylinder before you go out to make sure they are all pulling their weight

 

[boobie]

It's the little things that always get ya.

 

[toybuilder039]

Had one bad coil. Fixed that. I just rebuilt powerhead. It was first time In water running 24:1 gas for break in I fouled plugs choking it and by the one cyl not firing.

 

[toybuilder039]

How do u exactly do a drop test on each cylinder?

 

[boobie]

Run the motor at 2000 rpm and pull one plug wire off at a time with an insulated pliers. You should have equal rpm drop between all cylinders. If not, that is a problem cylinder.

 

[toybuilder039]

Ok thanks sounds simple enough.