with a 1.36 ratio that prop might be too much pitch.maybe you can borrow a smaller pitch prop to test.

i think donzi matt,s idea is a good one and pretty easy to do.

I'm definitely going to look at the wiring. I think the quickest way to eliminate wiring to the coil might be to run a hot wire straight to the battery. Before I do that I might just eliminate the circuit for the choke and fuel pump that run off the positive side of the coil. If that doesn't fix it, then the hot wire to the battery might tell me if it is a problem in the circuit coming back from the key that is getting me.

How much voltage should I expect to see across the coil leads with a DVM?

Jesus Christ .

Bud , I'd be willing to bet your boat wiring sucks azz. The purple wire from the ignition switch should provide more than 12v while running. Even though the alternator is prob putting out 13+ volts you rarely will see that at the coil because of the long run of wire from the 9 pin connector to the ign switch, then back to the coil.

I'd start with checking the voltage at the coil before replacing more parts

Also, I would lose the electric choke or at least NOT wiring it from the same wire as the coil.

Are you sure the choke flap is opening and staying open under throttle ? The symptoms you describe sounds like the engine is getting a gulp of fuel and no air upon acceleration . Look for the stupid little things that easily get overlooked first . Wire the choke open or better yet remove it , you don't need it anyway .

Right from the Holley Literature.

Connect the long wire from the kit to the posit
ive choke cap terminal marked (+). Connect the oth
er end of the wire to a
fused ignition activated 12V source. The choke cap
should only get voltage when the engine is running
. Check your
voltage source with a voltmeter.
WARNING: The distributor side of the coil is not a
12V source. Connecting the choke cap to the ignit
ion coil will
result in unacceptable choke operation and possible
engine misfiring resulting to possible engine
damage. Do not connect the choke wire to the coil!

Bud, if you have a stock 3 wire merc alternator, i am pretty sure you can power the coil from the purple wire coming from the alternator. It should only provide 12V when the engine is running. Verify that first with a meter though.

I would remove those and wire them to something else.

You cant measure across the coil leads for voltage as the ground side is pulsed by the ignition module. Ground to the engine block and measure the power side of the coil.

I certainly would not share the fuel pump and choke wiring with the coil. If anything, run a separate relay to power the fuel pump. Ideally it should be run through an oil pressure safety switch so the pump won't just run with the key on and engine off. It isn't really a difficult circuit to wire up correctly. Ditch the choke altogether, you don't need it, but if for some reason you decide you want it you can run that off of the relay for the fuel pump.

MT, it's the late Motorola/Prestolite style that Merc was using back in the 80's. It does have a purple wire attached that I believe is the ignition feed.

And you are correct - the wiring on this boat is pretty clustered up. They were pretty bad straight from the factory, and this thing is 27 years old and has been through several owners who had their hands on it. I have cleaned up some of the wiring at the helm. Guess I need to move the engine wiring harness up higher on that list. And yeah, total "duh" moment pulling the choke lead from the coil. That being said, it ran fine like this two years ago with the other engine. I hope this is it - it would be a much easier fix than poring through all the grounds and wiring. Thanks for the help.