Can a dead battery affect performance?

[starkyb]

My friend has a 1983 Mariner 90 horse. After he replaced the stator and 2 power packs we took it out for a test run. His cranking battery was dead so we jumped it from his trolling motor battery. The motor ran great for a while then started bogging down when in gear. His rectifier is bad and what I was wondering is if the battery is dead or very low and not charging, could that cause the motor to run poorly?

 

[Texasmark]

Re: Can a dead battery affect performance?

If the engine had a magneto, it could run without a battery. The magneto is a magnet on a flywheel that moves past a coil of wire wound around an iron core (to boost performance). As it passes it generates an electric pulse in the wire and that is sent to a transformer and is converted to high voltage that is applied to the spark plugs and fires the plug. No battery involved.

On newer CDI systems, they add a stator winding whose job it is to generate voltage in the same manner, but lots more energy to charge a "Capacitor" in the Capacitor Discharge Ignition system. Now we have a big chunk of energy ready to go through a transformer and "whack" the plugs with like 40,000 volts open ckt capability and very fast rise time, vs the early days 18,000v with a slow rise time. With the extra voltage and fast rise, dirty plugs fire much more easily.

The CDI still needs the trigger as before so you have 2 sets of coils for that. Then you could have a third set that generate energy that is sent to a rectifier to recharge your battery.

If you have any electric components in your ignition system that require 12v then your battery voltage being low definitely could cause engine problems. You really have to look at a wiring diagram for your engine to know for sure. Usually manual start engines are self sufficient in firing the plugs and have no battery charging coils. Also either your rectifier wasn't putting out 12v or your battery was so low it pulled the charger output down below a level that was adequate to operate your electronic components.

Mark

 

[Faztbullet]

Re: Can a dead battery affect performance?

I was wondering is if the battery is dead or very low and not charging, could that cause the motor to run poorly?

Yes as it will cause the stator to overheat....

 

[starkyb]

Re: Can a dead battery affect performance?

So that might explain why it ran good at first and poorly after some time on the water. What are some of the signs of an overheated stator?

 

[Texasmark]

Re: Can a dead battery affect performance?

So that might explain why it ran good at first and poorly after some time on the water. What are some of the signs of an overheated stator?

Faztbullet has come to the rescue. He can take it from here.

Mark

 

[Jlawsen]

Re: Can a dead battery affect performance?

The answer to your question is as Faztbullet states, most likely it's and overheated stator. The rectifier being bad is not allowing the battery to charge and the load seen by the stator is excessive and is being sustained for a longer than normal period of time. You'd be really lucky if you didn't find a bunch of blistered charging coils.

As was explained by Texasmark, the stator has both ignition and charging coils and although they are totally separate in regards to circuits they do live in the same hot house, so to speak, and can suffer from the excessive heat being generated at the charging coils. The trigger coils are completely separate from the stator but again, they live in the same house. If the heat is high enough, they can fire erratically and cause poor running conditions.