Why won't my no 1 battery start my motor?

[fish brain]

I have two batteries in my boat. Battery no 1 has not started my main engine since my re power in February.
It starts my kicker just fine and runs electronics all day long. Maybe it's just not big enough, its 900 cca and the new motor wants 800 cca so it should be good, tests fine, but maybe it's just not up to the job, so I go buy another battery and same problem, the fuel pump will prime, then when I go to start it, I can hear the solenoid click, but no turn over. I have even swapped battery no 2 into the no 1 spot and the problem is still the same in the no 1 position, and the new battery starts the motor just fine in position no 2, so the battery is good. I then thought my Blue Sea switch must be bad, so I pulled it apart to have a look, not even a hint of corrosion or discolouring. I guess I change the cables next? Am I missing something?

 

[23Hourston]

Break out the Multi meter.

 

[GLG]

I have two batteries in my boat. Battery no 1 has not started my main engine since my re power in February.
It starts my kicker just fine and runs electronics all day long. Maybe it's just not big enough, its 900 cca and the new motor wants 800 cca so it should be good, tests fine, but maybe it's just not up to the job, so I go buy another battery and same problem, the fuel pump will prime, then when I go to start it, I can hear the solenoid click, but no turn over. I have even swapped battery no 2 into the no 1 spot and the problem is still the same in the no 1 position, and the new battery starts the motor just fine in position no 2, so the battery is good. I then thought my Blue Sea switch must be bad, so I pulled it apart to have a look, not even a hint of corrosion or discolouring. I guess I change the cables next? Am I missing something?

I had a similar problem on mine and it turned out to be corrosion inside the lug on the negative cable. Close inspection of the lug indicated corrosion. It was hard to see at first but bending the wire exposed the corrosion. I took the cable down to my friendly wire & bolt dealer and put a new lug on after cleaning up the wire.

 

[adrian1991]

check your connections, make sure your ground and power wires going from your motor to the battery or selector switch are secure and clean of corrosion
If that dosnt solve the issue check to make sure your selector switch is not buggered up on the one selection

 

[fish brain]

I had a similar problem on mine and it turned out to be corrosion inside the lug on the negative cable. Close inspection of the lug indicated corrosion. It was hard to see at first but bending the wire exposed the corrosion. I took the cable down to my friendly wire & bolt dealer and put a new lug on after cleaning up the wire.

I'm going to pull the wires today and inspect them from end to end. I am suspecting a bad ground, I might throw on a set of jumper cables from ground post to ground post before I pull them cuz it won't take any time and may pinpoint the problem

 

[fish brain]

check your connections, make sure your ground and power wires going from your motor to the battery or selector switch are secure and clean of corrosion
If that dosnt solve the issue check to make sure your selector switch is not buggered up on the one selection

The wires look good on the surface, I have taken the selector switch apart and it looks brand new inside

 

[trophywife]

would your weak battery possibly be not getting a charge from the alt?
multi meter questions..

 

[fish brain]

would your weak battery possibly be not getting a charge from the alt?
multi meter questions..

I swapped the batteries from side to side. The battery that would start the motor in position 2 will not start the battery in position 1 and the no 1 battery will start the motor when in position 2 . I did test the battery with my battery tester before hand. The problem is definitely in the no 1 circut

 

[noluck]

switch the number one and number two battery cables on the battery switch, that will isolate the cable or the switch

 

[profisher]

I'm going to say bad #1 wire..those switches stay really clean internally. Probably a split or hole in the wire that has allowed salty moisture to turn a section of the copper green.

 

[AlK]

I'm going to say bad #1 wire..those switches stay really clean internally. Probably a split or hole in the wire that has allowed salty moisture to turn a section of the copper green.

X2

 

[ReelSlim]

I’ll play devils advocate here and arm chair troubleshoot and say it’s a bad switch. Blue Seas are better than Perko but I have seen them fail from stress and corrosion. I’m heading back to the Island on Monday and just replaced my 1 year old switch. You can have it... it’s still like new. I didn’t need it because when I installed my ACR last week I used the switch that came with it. Use you booster cables and bypass each connection in and out of the switch and also with it bypassed. 3 quick tests and you’ll find the bad apple....lol

 

[fish brain]

I’ll play devils advocate here and arm chair troubleshoot and say it’s a bad switch. Blue Seas are better than Perko but I have seen them fail from stress and corrosion. I’m heading back to the Island on Monday and just replaced my 1 year old switch. You can have it... it’s still like new. I didn’t need it because when I installed my ACR last week I used the switch that came with it. Use you booster cables and bypass each connection in and out of the switch and also with it bypassed. 3 quick tests and you’ll find the bad apple....lol

Thanks for the offer, but it's definitely not the switch. I took the switch apart and inspected it it looks brand new. I did double check by swapping the wiring around so that battery 2 connected to the no 1 side and everything worked so I'm calling the switch good. I took the wires in to my local supplier, he was run off his feet, so couldn't make me a new set today, but he promised them for tomorrow morning. I will know tomorrow afternoon for sure if it's the cables

 

[fish brain]

Problem solved!
Turns out I needed to ground the second battery directly to the engine. The way the boat was wired when I swapped my motor, was that the two battery grounds were connected directly together and the motor only grounded to one battery, and I just left it as it was cuz it worked. So battery one in my case was the absolute furthest from the starter and that's why it wouldn't turn the starter. I ran a new wire from battery two to the ground terminal on the engine and it works perfectly.
Thanks to everyone for their thoughts

 

[noluck]

put in a ground Buss bar

 

[MadJigga]

put in a ground Buss bar

Every boat should have one

 

[fish brain]

put in a ground Buss bar

I have one but it is fed off the common battery, it is not wired to both batteries. Should I tie both batteries to it?

 

[Foxsea]

I have one but it is fed off the common battery, it is not wired to both batteries. Should I tie both batteries to it?

All grounds should be interconnected.

 

[ReelSlim]

I have one but it is fed off the common battery, it is not wired to both batteries. Should I tie both batteries to it?

Yes....Just jump between each battery and then go to a common bus.

 

[Brando]

I would ditch the 1,2 switch in favor of the acr system. In my opinion it’s a far better setup. You can then run one house(deep cycle) and one start battery and the system will regulate the charge itself. The switch is just on/off. Starting on a deep cycle will wear it out prematurely as will deeply discharging a starting battery running electronics and riggers all day not how they were designed to be used.

just my opinion maybe worthwhile when it’s time for new batteries?