merc 3.o battery size

[gnashin]

What would be the best size battery for a 140 merc 3.o. cranking amps? Also how would I test a starter to make sure it is working properly? ? Thank you and safe boating

 

[UncleWillie]

Re: merc 3.o battery size

From another Post, long ago and far away....

Mercruiser 3.0L --- My owner's manual says "Minimum 375 cca/475 mca/90 Ah" ...

Most any Group 24 Battery will fit the bill.

Unless you have a specific reason to suspect otherwise; If the starter starts the Boat, it is working properly.

A simple Test.
Disable the ignition. Trip the Lanyard Kill Switch at the throttle.
Crank the engine for a full 10 seconds.
If the starter is cranking after 10 seconds without starting to slow down, The battery and starter can be assumed to be functional.

 

[gnashin]

Re: merc 3.o battery size

Thank you very much

 

[fishrdan]

Re: merc 3.o battery size

Group 24 will work just fine, but bigger is better in case you have engine start issues and need the extra power from a larger battery.

I used the exact same battery in my boat, that my V8 truck uses. In the event that the truck battery dies I can rob the boat, if the boat battery dies I can rob the truck. I had to use those funky brass automotive-marine terminal adapters, but they work fine.

(This is an automotive battery and not a "marine" battery, so I'm sure someone will comment on that....)

One bonus is that an automotive battery warranty is much better than a marine battery warranty.