Mercruiser 260 stalling out

[kybishop]

Seems the majority are quick to ditch the points and "upgrade" to the electronic ignition. Points are pretty simple and inexpensive to keep going and reliable when kept up. The great thing about points, as our mechanic has pointed out so to speak, is you can typically get back home when something goes wrong. You may have to idle in or limp in but majority of the time you can get back in. With the electronic ignition when something goes bad, you are typically and literally dead in the water.

 

[BonBini]

If your currant problem was stemmed from a shorted battery your volt gage would head south. With low voltage your coil output would be in direct proportion with input voltage. In turn you wouldn’t have enough spark to jump much of a gap at the plugs. You’d be experiencing misfiring when you filled your cylinders with a greater volume as in the upper rpms or greater throttle angles.

As far as those points go: Be sure your wired up correctly. Voltage to the coil is typically stepped down to around 8v ish for normal running. However during cranking, a attachment wire from the starter to coil gives 12v coil feed for a hotter spark for starting… Wich brings up another test instrument, Your Tach! It should get a signal from the neg side of the coil. If you lost power to the coil, your tach would be acting up too.

Now back to the electronic ign: With electronic ign you'll get a hotter spark for a better burn. So you'll be saving the planet while you boat. :grin:

 

[kybishop]

Ahhh, and I thought the green part of power boating was that which you dump into it...

Good point(s)

 

[JVM225]

Run the boat with the battery switch on both. When anchored (or not running the boat) and running lights etc., just use one of the batteries so that the other is strong enough to get you started when it's time to go.
Your problem sounds to me like ignition (electrical) related. You said you have points; I guess that means no ignition control module. That turned out to be my problem when I had the symtoms you have.
I would start by checking all connections first, then the coil, then the distibutor itself.