Bad battery or starter?

[salty_waders]

I have a 2002 115 hp 4-stroke. Fished all day and the motor started fine all day. Woke up to go fishing again and "click." The battery was only 4 mo. old. I briefly charged the battery and then tried again. The starter rapidly clicked trying to turn over the motor. We tapped on the starter with a wrench and it started. Later I returned the battery for a new one and the motor started fine with the new battery. But now I dont know if it was the starter/relay or the battery? So my question is, will the starter still start the engine with low battery power if the starter is tapped on? In other words, if the battery didnt have enough power to fully engage the starter, until I tapped on the starter? make sense?

[Bilge Rat]

The battery cables are probably over 10yrs. old check the ends. Look for corrosion, loose strands of wire at the connectors. Replace the ends if they look bad. Both positive and negative cables. If the wire in the cables is green/corroded up onto the insulation cut it off or replace.

Clean the ends at the battery and the motor. A very little amount of corrosion and/or loose connection will give problems.
Get rid of any wing nuts on the battery connections. Use SS lockwashers and nuts.

In short, get all connections clean and tight.

Do you have a battery disconnect switch? They get corroded over time, Perko is bad about a contact going out. If suspect replace it with a Blue Seas switch, they seem to last.

Those starters are very reliable, weak connections/batteries are more common.
A weak connection is hard on a starter.

Make sure to rule out the easy/cheap causes before spending big money on a starter only to have the same issue.

Tapping on the starter sometimes wiggles a weak connection both inside and out on the starter.

Don't forget the negative leads.

[TownsendsFJR1300]

Juat to add to the above(which is the likely issue).

Get the battery load tested to rule it out as GOOD.

If you have a volt meter, with the engine running (with water to it), check the voltage at the battery, just to verify the charging system is indeed charging (should be arounf 14 volts). If its 12.8 or lower, you have some problems..

Good luck and please post what you find.

[salty_waders]

Thanks guys, good advice. The battery cables are in great shape. If the motor starts fine with the new battery should I worry about the starter/relay? Can the starter relay work intermittently? I just dont want to get towed in again. Thanks for the help!!

[TownsendsFJR1300]

I'd first make sure the engine is charging the battery, 14 volts or so running.

If it isn't, the engine will run on the battery for only so long before it dies...

I'm not that familiar with the Yamaha starter on that engine but, most likely, if it keeps cranking it up (after several tests) I wouldn't worry about the starter.

The only Yamaha starter I've seen fail (on-line) was a motorcycle (FJR1300-large sport tourer). That bike as I re-call, had approx 150,000 miles (very much run, and yes that is high mileage for a bike). It was loaded with oil and crap from years and years of service.

I suspect you could also pull the starter off the engine and bench test it, literally powering it up, smacking as you did on the boat and make note if anything affects its performance.
If tapping/smacking it affects it, somethings loose/not right with the starter.

I don't think I answered your question thou re the relay. I'm not familar with it so I really can't comment on it specifically.

[salty_waders]

stupid question but...when I check the voltage at the battery when running, Do I literally check it the battery terminals? thanks again! you guys have been a great help.

[TownsendsFJR1300]

stupid question but...when I check the voltage at the battery when running, Do I literally check it the battery terminals? thanks again! you guys have been a great help.

Yepper!

Not running, the battery should be around 12.8 volts.

Once started (on rabbits ears or in the water) just put your volt meter on each terminal of the battery directly, it should be close to 14 volts or work its way up to 14 volts with some RPM's.

If it stays at 12.8 volts or starts dropping, the system is NOT charging, your literally just running off the battery..

Please post the #'s you come up with, your likely fine..