Annoying battery

[tangentair]

I have this "came with the boat" battery and a Merc BF50. The battery is sitting at 12.5 volts (read with an expensive DVM) and it powers the engine tilt and other things fine. It just does not seem to have enough power to turn over the engine. When I attach the 10 amp battery charger the engine starts immediately, but the same battery charger also says that the battery is fully charged.

I tried a jumper battery/battery assist and it would not start the engine either. And yes I checked the terminal contacts. Anyone else have a BF50 that does not want to turn over on a battery with a medium charge.

[Moe]

What is the voltage across the battery when the key is in the start position, but the motor isn't turning over?

Same question, but between the starter plus and ground connections on the motor?

[kmclemore]

Hmm... on first cut it sounds like it might be a sulphated battery.... and that means replacement. But do the diagnostics that Moe recommends - he's one of our best electrical guys.

[baldbaby2000]

Do what Moe suggests. You may have corroded connections but I suspect your battery needs replacing if you can start OK with the charger connected.

[Bobby T.-26X #4767]

i had a similar problem.
turned out to be the size (or lack thereof) of the cables.

while turning over the motor, i felt the cables.
the very small cables were hot, hot, hot!

so i changed out and "upped" the cable size two notches. wow...what a difference it makes. turned right over with no heat build-up.

Bob T.
"DāBob"
'02X w/ '04 90-TLDI (14" x 11 pitch)
Dinghy Motor: '06 2.5-Suzuki

[James V]

The stock battery is the standard car type battery where you can check the water and fill. I would also open it up and check voltage from cell to cell. Should be around 2 volts. You may also have a dry or almost dry cell.

A lot of battery places can check a bad battery. Do this last.

[hvolkhart]

I had the same problem.
I changed out the battery and now it is working fine.

[Craig LaForce]

Make sure you have water in the battery up to the top of the plates.

I see you have an 07 M, so the battery should be 1 year old? constant charging in hot weather will dry out a battery very quickly.

A small battery hydrometer is also handy for checking each cell for a good charge.

[RandyMoon]

I had the same problem last weekend. I took both batteries out (man, that was a bear getting them out) and took them to Sears to get tested. One of them was bad, but the charger kept acting like everything was OK.

Wrks great now.

[tangentair]

sorry about closing this so late - lost internet access for a while - the problem turned out to be a bad charger. Motor ran fine after replacing charger and doing a slow charge over night. Thanks for all the replies, at least now I am comfortable that all my wiring is tight and sized well.

[opie]

http://www99.epinions.com/boat-Motors-All-Honda_50

A great engine!
by neilfrazer , Mar 23 '05

Read the review by Neil Frazer. Good list of things to watch for on a well used and useful Honda BF50A. He predicts all of us with a Honda 50 should expect a charger replacement at 500 hours. He has a good checklist of parts to have on hand in your boat.

[Catigale]

It is important to note here that the fuel pump did not fail catastrophically; all that happened is that the oil level began to increase in the crankcase

Sometimes these reviews arent as useful as the writer may think