Stumble and Backfire during accel

Anyone have a picture of how they mounted the coil? I have read the posts about mounting it vertically for longer life. It seems quite constrained with the wire lengths that are provided...

Sorry my comment wasn't helpful. Can you use a timing light while engine cranks to find out where you are at?

Ahh, I see what you mean. The dizzy (distributor) is in sync with the camshaft though, not the crankshaft. So, it only turns once with every two turns of the crank and therefore there are 8 firing events per 360 degrees of dizzy spin.

Since we're on it, I'll mention one pitfall, make sure your number one cylinder is at top dead center of the compression stroke... not the exhaust stroke.

Also, don't overthink the "points" opening aspect. When you loosen the clamp bolt, you get (almost) infinitely fine adjustability. Another words, you could theoretically adjust the timing by one degree or a half a degree of a tenth of a degree, if you were using some sort of robotic protractor hand instead of human fingers.

ski_in6 wrote: Anyone have a picture of how they mounted the coil? I have read the posts about mounting it vertically for longer life. It seems quite constrained with the wire lengths that are provided...

Here is where I mounted mine. I had to fab a bracket to make it work.

I’ve got a similar problem to that experienced by ski_in6. I’ve got a ’94 Ski Nautique (closed bow) with a Ford 351-based PCM engine with 600 hours on it. She starts right up, and is fine for maybe ten minutes or so. But then, she begins to stumble, and sometimes even dies, when I give it a lot of throttle rapidly. If I inch the throttle up very gradually, she’s fine. At other times, she accelerates fine under heavy throttle, but within a few seconds dies suddenly and completely, as though the ignition key has been turned off.

In either circumstance, I remove the distributor cap and replace it. She goes back to operating perfectly, and the cycle begins again. It’s unclear whether the fix derives from removing and replacing the cap, or just from letting the engine sit for a few minutes while if fiddle with the cap.

She’s had the problematic Pro-Tec ignition system replaced. She was tuned up spring of last year, at which time the plugs, wires, and distributor cap and rotor were replaced. The carburetor was rebuilt this spring, and the fuel filter changed out at the same time. I just recently replaced the distributor cap again.

I had been thinking that the problem was ionization under the distributor cap, and had planned to install a vented cap, but now I’m thinking that’s not likely to be the solution, given the prior entries in this thread. (I’ll probably do it anyway, since a cap is cheap.) Also, the bowl of the distributor is vented. Although I haven’t checked to see whether the vent might be blocked, I doubt that’s the case, as the bowl was new a couple of years ago.

I’m now thinking that the problem with the stumbling might be the coil (even though it was new only a year ago), and the outright dying might be a bad connection in the wiring behind the dashboard. Or possibly both symptoms are due to the latter possible cause.

Any thoughts?

We felt the coil last time we had this problem and, yes, it was hot. Although I'd expect it to be at least warm when operating normally. How hot is too hot? Such that you can't keep your hand in contact with it for more than a split second?

Electronic.

I didn't test the horn or the nav lights, but I think the blower cut out as well. I'll check again next time it happens. You're thinking it's a problem with the wiring behind the dash?

Thanks. I'll try all of those suggestions.

Electronic. Or so the mechanic tells me. I wouldn't know the difference.

This will help somewhat, but you really need to see under the cap to know:
http://www.skidim.com/distributor.asp

Under the cap, an electronic would look something like this:


And points would look something like this:

It sounds like coil. Either the coil itself is bad, or it the ballast resister isn't wired in correctly.

It seems like a lot of those Protec to Distributor conversion kits came with a less than great coil. I've heard good things about the MSD Blaster II as a replacement.

Sounds like a plan.

I'm sure you realize that if you're getting an interruption in your ignition (purple or red), no coil is going to help.

But, in the interest of time, it's going to take a few days to get a coil in hand, probably doesn't hurt to order it as it's a likely suspect if you're engine is cutting out and all of your dash functions are still working.

Basically, the dash power source (Battery Positive) wire is red. Usually the ignition wire switched on by the key is Purple.

When I say interruption, I mean a break or open in the circuit. This is normally a switch, but if you've got something funny going on like a loose or corroded connection, this is going to act like a "switch" and open or interrupt the circuit.

What I was getting at, is your coil needs a steady, un-interruped feed of positive current to work. The positive current wire should be purple, but it might be red. If the circuit is opened (flow is interrupted) then the coil won't do it's job of making spark, no matter how good it is.

This diagram should help:

While I have your attention, do you know the answer to this question:

I have a 1994 Ski Nautique closed bow with a PCM engine. The plate on the engine says it's a model PLP-PR-R12PT. My owners' manual seems to say that the boat could possibly be equipped with any one of the following four engine models: PLB, PL&RC, PL&RD, or PL&RP. Can anyone tell me which of those four is mine? What's the logic that maps the number on my engine to one of the models listed in the manual? I can't find anyplace in the manual where this is explained.

Wow. It had never occurred to me that the engine might have been swapped out at some point. I bought the boat in 1992, becoming its third owner. At that point, the hours read (for whatever that's worth) 300. The engine looked like old technology, even then. It looks like the pictures in the manual, although those pictures are of poor quality, so it's a bit hard to say for sure.

I went onto the CorrectCraft site about a week ago and posed the question to them. I've not had an answer yet.