351 W Distributor

My Nautique, 351 W. Reverse rotation. I bought it years ago not running. Previous owner had a high dollar distributor in it. It was bad. So, I bought a $50 distributor at the local parts store, changed the bottom gear to the gear I removed from the old distributor. Boat ran for 1 year. Then no fire or very little.
It's a simple points and condenser firing system. Distributor was under warranty, So I changed it with another, and again swapped the drive gear. Now it ran for 2 years. Failed again. Cleaned points, checked gap, replaced condenser, still not enough spark. It had spark, but so dim you couldn't see it. But trust me, it was there. It bit me. LOL
So I changed the coil. Still no different. Hummmm
Screw it, grabbed another $50 distributor. BAM, fired right up. Ran for one hour. Ran great too. Then, down again.
Back to parts store, bought a $75 distributor. Dropped it in. Never missed a lick. Ran all weekend pulling skiers...

What do all you recommend?

Thanks

As Pete asked, maybe the points rubbing broke wore quickly & the gap changed. Or they burned from bad condensor or not having proper ballast resistor.


If it fails again, use a ohm meter to figure out where it has lost conductivity.

Certainly there are no marine distributors available at 50 or 75 bucks so I would be wondering about what you are doing with the vacuum advance and whether you are close to a decent ignition curve, not to mention the whole safety issue with using automotive parts .   

Other than that using a points distributor usually requires the proper ballast resistor... and cheap points are junk

Let me try and answer all the questions. LOL
Yes, I gap the points, and use a bastard file to clean them.
No, I have NOT checked Dwell. But I will
You are correct, it is not a marine distributor. It is an auto. Thats why I have to change the drive gear.
Alternator charging correctly and voltage is good. The wiring is all original and looks great. Only electrical issue it ever has is just like most all these older ones. Turn bow lights on and gauges go nuts. Wiring too small for lights.
The resistor could very well be the issue. However, when the last distributor that bit the dust, I jumped the resistor and it made zero difference.

You're probably familiar with the differences between a marine and an automotive distributor so that's your choice what you want to use

Sometime you may find yourself changing your undies after an unexpected big boom sends you airborne though

I'd check the resistance of the ballast resistor with nothing hooked to it. It should be about 1.2 to 1.3 ohms

A good number is Echlin ICR-23 from NAPA or you can cross reference it to a bunch of other brands. They cost less than 10 bucks.

Your points last a lot longer with a ballast resistor in the circuit.

No vacuum is used.
We have hurricane on it's way here, I just went to the lake house and pulled the boat out. I ran it wide ass open from my dock to the ramp (few miles). It never missed a lick.

So now I am curious. I'm no gearhead so there is a lot I dont understand, so I am just trying to learn.

If he has an auto distributor with a vacuum advance but is not using/not hooking up the vacuum, how is it advancing?

I also wonder if that wideass open run from the dock to the ramp fell within that 30 - 60 minute lifespan of his distributors. Again, just curious.

75 Tique wrote: If he has an auto distributor with a vacuum advance but is not using/not hooking up the vacuum, how is it advancing?

Larry,
With no vacuum, there's no advance or retard. I suspect the engine performance isn't the greatest.

8122pbrainard wrote: 75 Tique wrote: If he has an auto distributor with a vacuum advance but is not using/not hooking up the vacuum, how is it advancing? Larry, With no vacuum, there's no advance or retard. I suspect the engine performance isn't the greatest.

Larry

Pete might be a little retarded when it comes to vacuum advance

A distributor with a vacuum advance mechanism also has a mechanical advance mechanism just like the marine distributors.

It could be long and dragged out and fill pages of reading but the short version is that vacuum advance adds advance under low load high vacuum conditions like driving downhill, highway cruising etc to maximize efficiency and fuel economy.

If you could read your timing from the drivers seat of the car you might see around 50 degrees advance under these light load conditions and then when you punch it the vacuum falls off and the advance added by the vacuum falls off too.

Fuel injected stuff can do all this advance magic through the use of all those sensors feeding the ECM and the ECM makes the same adjustments that mechanical and vacuum advance could make together.

It wouldn't hurt to have it hooked up on a boat as far as advance goes but the hole in the distributor where the mechanism hooks up leaves a nice path for those explosive gases to find a spark and go Boom. With it disconnected you still have the mechanical advance function and the boat will run good just like with a mechanical advance distributor.

Like I said before there's a lot more to vacuum advance but here's a good basic article in the link


link

75 Tique wrote: So now I am curious. I'm no gearhead so there is a lot I dont understand, so I am just trying to learn. If he has an auto distributor with a vacuum advance but is not using/not hooking up the vacuum, how is it advancing? I also wonder if that wideass open run from the dock to the ramp fell within that 30 - 60 minute lifespan of his distributors. Again, just curious.

The distributor likely has both a vacuum and a mechanical advance - there is no reason to think the mechanical advance isn't working. However it may also be too much advance, too little advance, too slow or too fast of an initial advance, and too slow or two fast of a final advance for the application.

And in this relatively lightly loaded application none of that may make any difference at all to the guy driving it...

KENO wrote: [QUOTE=8122pbrainard] [QUOTE=75 Tique] It wouldn't hurt to have it hooked up on a boat as far as advance goes but the hole in the distributor where the mechanism hooks up leaves a nice path for those explosive gases to find a spark and go Boom. With it disconnected you still have the mechanical advance function and the boat will run good just like with a mechanical advance distributor. Like I said before there's a lot more to vacuum advance but here's a good basic article in the link link

The vacuum hole, where the hose would hook does have a stopper over it. LOL
I'm old, but not totally out there. Just like the blowers.
Turn them on BEFORE you start the engine. And not just before you start. Give them a few minutes. Recommendation is 10 minutes.

Peacock wrote: I'm old, but not totally out there.

I would question exactly where you are. .

Is this in your future? How's your insurance? Is there a fire extinguisher on board? Maybe two would be better!

Wow... Tough room..   

BR should be above the bell housing, next to the 50A breaker.