F115 Turns over hard

[Kodiakan]

Port F115 turns over hard and then starts and runs fine. Also, when starting it draws so much juice that the Chartplotter re-starts. Tonight I cleaned the battery cables/wires and checked battery voltage which was fine. Due to working to much and playing to little boat has been used very seldom this year and is docked full time in saltwater.

[greasyshaft]

Monitor battery voltage at the battery when cranking (kill lanyard off) and then at the sounder when cranking, should be little to no difference.
If there is a difference between the two voltage readings go hunting for damaged/corroded bits.
Makes sure the sounder is not getting its power from the Yamaha control box (if so it is wired wrong)

I assume you are running one battery.

How old is your battery? have it load tested.

[Kodiakan]

2 Batteries tied together. Fairly new optimas, always kept indoors and charged. I will continue to check for a bad wire. Just thought someone had had the identical problem. Could not find anything in archives. Thanks for reply

[TownsendsFJR1300]

Do you have a "Perko" Type, on/off/both switch for the batteries?

Its not un-common for the connections inside to get crappy or the cables loose inside.

I would get those batteries load tested (you can have a new/old battery that has plenty of volts but can't handle the amperage pull when cranking) and once one is known as good, hook up directly to the engine cables, by passing everything else. Then see how fast it cranks over..

[Kodiakan]

Thanks Scott. I keep a spare battery on the boat. I'm going to hook it up directly to engine and see results. Thanks for triggering the idea....

[TownsendsFJR1300]

Your welcome, please post your results, final fix and good luck..

[Kodiakan]

Fixed

You nailed it Scott. Battery read 12.6 volts but when a load was put on it there was nothing. 3 year old Optimas. I'm going back to wet cells. Thanks for the help......

[TownsendsFJR1300]

Cool. Nice simple fix..

BTW, I've read separately (and Rodbolt has posted) that most if not all Yamaha outboard engines should use wet cell batteries.

The topic came up not too long ago, the charging system doesn't seem to work well with anything other than a wet cell.


If you can keep an automatic 1.25 amp is plenty on it most of the time its NOT used, you'll get much longer life out of the battery.

I have a .8 amp (a bit on the small side but it tops off the battery) waterproof Deltran automatic charger actually attached to the boat lift. I'll flip power on to the dock (and charger) for a couple of hours each day.