Double-checking ignition tests - 77 85hp

[iwombat]

Well I had no/weak intermittent spark on #3. This motor has the single power-pack.

Took out all the plugs and performed the following tests.

1)swapped wires from power pack to coil between #3 and #1. #1 Didn't fire and #3 did. Problem doesn't appear in the coil.

Put the wires back to normal.

2) Swap #2 and #4 feeds from timer base with #1 and #3 feeds. Problem moves to #4.

Put wires back to normal.

3) Reset the air gap on the timer base using the proper tool. Now get a better intermittent spark on #3 but still not good.



Seems like a timer base to me, but before I drop $250 I'm tossing it out to the group-mind for comments.

 

[iwombat]

Re: Double-checking ignition tests - 77 85hp

Well, I went to go double-check the air gap settings and found that my flywheel wasn't seated properly when I torqued it down - d'oh!

Fortunately, I had another key handy. Fires on all cylinders just fine now.

I'm wondering now, if I should just replace the timer base at the end of the season. Do these things go out of adjustment often? It seems like something that shouldn't really happen.

 

[iwombat]

Re: Double-checking ignition tests - 77 85hp

Took it out on the lake today.

5.5k WOT RPM and 38mph on the GPS. Runs better than it ever has.

I think that must've been the source of my slowly deteriorating performance. I must have had weak or intermittent spark off the timer base all last season. I never could diagnose it until I got a multi-cylinder spark checker and I could see #3 miss in comparison to the other cylinders. Chalk one up to having the right tool.