Jumping an outboard motor from 36 volts ?

I was fishing last week out on the lake and found a hot spot.

We fished in the same area for about 6 hours and never started the outboard. I was running two locators and the live well both draining power off of my main starting battery.

I found my self in the middle of the lake and my outboard would not start. I tried my portable starter pack and that didn’t do it. I tried using jumper cables from one of the batteries that I had hooked to my trolling motor that didn’t work either.

My trolling motor is a 36V Terrova I figured with 3 batteries there would have been enough power to turn the outboard over but it didn’t.

Is there a proper way to jump my outboard using my trolling motor batteries?

Should I remove one battery from the series?

Any advise you have would be great.

This is the 3rd time I have been out and had a dead starting batter over the last 5 years.

First of all I think you need to have your batteries fully tested with the load applied!
I carry large wire gauge jumpers (20 footers) and never have not have been able to aid myself or any other!.

take the hood off your motor and see where power goes to the starter. Hook up pos cable there and neg to a ground . the other end would hook on one battery as normal

I had problems when the jumper cables I tired to use were of an insufficient gauge to supply the required current to the motor.
I was unable to jump from my TM batteries
or
the other boat that came to my aid.
I since acquired larger gauge cables and no longer have this issue.

I also tend to run my battery down with my electronics and radio/cd player.
I have a Humminbird locator and in the
menu
alarms
I set the minimum voltage alarm to 11.5 volts.
This is what the Mercury staff said was the minimum for my 90HP 4 stroke.
When the alarm goes off, I start the motor and charge the battery.

Is your boat fuel injected? is it greater than 25hp?

If the answer is yes to both questions you need a functioning 12V battery to run.

Swap ONE of your trolling motor batteries with you starting battery and pray.

Good luck

I would suggest a dedicated starting battery if this has happened a few times.

No, you should not jump your OB off of 2 or 3 batteries hooked in series. You need to disconnect one and jump from it. If you try jumping the starter battery with a 36 volt system you stand a real good chance of screwing up your electronics on the boat that are turned on when you jump it as well as OB electronics.

I suggest replacing your main battery. Upgrade to 29 or 31 class marine cranking or dual purpose battery, not deep cycle. Hope this helps.