what is the minimum voltage of a starting battery to start a Johnson 90 v4 outboard?

[ib18]

what is the minimum voltage of a starting battery to start a Johnson 90 v4 outboard?

Hi, I took my boat out fishing this weekend. It started after 3 cranks so we left the dock. Got to the stripers fishing hole, and shut the Johnson 90 off and using the motor guide 24 volts 75# wireless trolling motor. And started the Johnson 90 again after 2 cranks to go bottom fishing when surface stripers dissipated. We found the spot and started to catching white perch immediately. Used trolling motor a couple times. Time to head out to deeper (60 feet) spots to live lining the small perch. And it started without any problem. Troll with 24 volts a little more and fished. At the end of the day, we were ready to call it a day. But, I could not start the Johnson 90 after 3 cranks. I didn't try starting Johnson 90 again fearing it could drain the batteries down and we would not be able to use the trolling motor to go home. It took us about an hour to troll back to the dock at 2+ miles per hour under 1 foot of wave and 5 knots wind.
My 2 deep cycle marine batteries are rated 29HM from Advance Auto Parts with 675 cold cranking amps, 840 max and 210 reserve capacity.
Can't wait to mount my kicker motor - Honda 8 hp 4 stroke.

 

[GA_Boater]

Are you using the deep cycle batteries as starting batteries for the Johnson? If so, that's your problem.

 

[racerone]

Have you taken this starter apart for inspection.----Many posts on this woderfull motor and I can't recall if that was done.

 

[Fed]

Minimum 9.6 Volts across the battery POSTS while cranking.
You will have to stop the motor from starting while carrying out the test... pull the safety lanyard or ground the kill wire.
Manual says 9.6 Volts while still cranking after 15 Seconds the battery is considered good.
Your starter motor doesn't know or care if you're using a start battery, a deep cycle battery or even flashlight batteries so long as the output is up to spec.
Minimum 360 CCA for a V4 crossflow.
Maximum allowable Voltage drop between battery & starter motor is 1.0 Volt.

Do some testing first it's cheaper & easier.

 

[GA_Boater]

Your starter motor doesn't know or care if you're using a start battery, a deep cycle battery or even flashlight batteries so long as the output is up to spec.

Agreed, but IB's description of the issue is saying he's using the 2 DC TM batteries to also start the motor and implies the boat has no dedicated starting battery. If that's the case, the batteries can be drawn down after using the TM to the point that motor won't crank.

 

[Fed]

Yeah it's a bit messy GA, given the $$ and the space a dedicated battery for the motor would be my preferred way to go.
Then charge the TM batteries at home with a quality charger and maybe keep some jumper leads on the boat for emergencies.
Lots of alternatives to play with IB21, don't forget you can rope start the 90.

 

[ib18]

Are you using the deep cycle batteries as starting batteries for the Johnson? If so, that's your problem.

What kind and size of battery should I be getting then?

 

[ib18]

Have you taken this starter apart for inspection.----Many posts on this woderfull motor and I can't recall if that was done.

No this year, last time I took the starter apart to clean the starter inside was April 6, 2016. So, I will take it apart this weekend to rebuild it.

here is a playlist of video of how I rebuilt the starting motor.

 

[ib18]

Minimum 9.6 Volts across the battery POSTS while cranking.
You will have to stop the motor from starting while carrying out the test... pull the safety lanyard or ground the kill wire.
Manual says 9.6 Volts while still cranking after 15 Seconds the battery is considered good.
Your starter motor doesn't know or care if you're using a start battery, a deep cycle battery or even flashlight batteries so long as the output is up to spec.
Minimum 360 CCA for a V4 crossflow.
Maximum allowable Voltage drop between battery & starter motor is 1.0 Volt.

Do some testing first it's cheaper & easier.

Oh, Wow. Thanks for your tips. I ran the 2 batteries down to 11.8 volts and 11.7 volts. 40% level so they are way above the minimum 9.6 volts. I am taking apart my starter motor to clean the inside.

 

[ib18]

Agreed, but IB's description of the issue is saying he's using the 2 DC TM batteries to also start the motor and implies the boat has no dedicated starting battery. If that's the case, the batteries can be drawn down after using the TM to the point that motor won't crank.

yes, no separate starter battery. Too cheap to buy one! LOL

 

[ib18]

Yeah it's a bit messy GA, given the $$ and the space a dedicated battery for the motor would be my preferred way to go.
Then charge the TM batteries at home with a quality charger and maybe keep some jumper leads on the boat for emergencies.
Lots of alternatives to play with IB21, don't forget you can rope start the 90.

Thats what I should try!!! The engine was still warm.

 

[racerone]

Did you take an ohm reading from commutator to the stub shaft , yes or no ??----Should read infinity on a digital meter..----Those starters are easily damaged ,by the crank , crank hope it starts today approach.

 

[dingbat]

I am taking apart my starter motor to clean the inside.

I would clean the battery and starter terminal before tearing into the starter.
Having said that, I replaced my starter last year due to slow rpm.

Ebay is your friend

 

[oldboat1]

Oh, Wow. Thanks for your tips. I ran the 2 batteries down to 11.8 volts and 11.7 volts. 40% level so they are way above the minimum 9.6 volts. I am taking apart my starter motor to clean the inside.

I'm guessing you would not be getting 9.6v while cranking, given those voltages at rest. Having a similar issue with a couple of 3yr old deep cycles at the moment. I think I may have pretty much did them in with an onboard charger -- found them almost dry about a month ago. (Second time that has happened -- last time a year ago during marina storage).

I'm thinking my 3yr old batteries need to be replaced next spring, in part given the abuse (maybe a large part). I leave them on the maintenance charger at the dock during the season, and that probably is not the way to use deep cycles -- even if you are smart enough to keep the water levels up, unlike me.

Maybe your batteries are giving up the ghost....

 

[Fed]

I ran the 2 batteries down to 11.8 volts and 11.7 volts. 40% level so they are way above the minimum 9.6 volts.

Yes oldboat, ib15 you completely missed the point.

 

[ib18]

Have you taken this starter apart for inspection.----Many posts on this woderfull motor and I can't recall if that was done.

Yes, my wonderful Johnson 90 always started in 1 crank or 2 the most once the engine is warm. First cold start was maybe 5 cranks the most.

 

[ib18]

Thanks to all, I think I will get a third battery just for starting Johnson 90 to be safe. I did notice as my last dying attempt to start the motor. Each crank was slower than the prior crank of the 3 tries. It was almost like starter was dying or the battery was dying. I didn't try starting with the other battery. The second battery might have more juice left than the first battery. Ah! so many regrets. I could have come home more than an hour earlier. Wife would be happier had I made it back earlier - LOL My friend would not have missed his baseball game.

I wish - LOL:

1. I had a third battery for starting.
2. I tried starting with the second battery.
3. I had my Honda 8 hp kicker motor mounted.

 

[ib18]

Yes oldboat, ib15 you completely missed the point.

oh crap, had to re-READ what you wrote again.

Now, I get it - I need higher voltage when the 12 volts battery was resting.

The voltage drop as soon as I turn the key.