f150 won't start on just 1 battery

[gsdanno1]

what cables am I using to connect the battery to the starter in your scenario , Townsend ?

[gsdanno1]

I've actually done 5 voltage drop tests now , but they have all been through the battery switch. I'm just not understanding how to make a physical connection between the battery and the starter if the battery is no longer hooked to my cables. Am I to use jumper cables - I did this this afternoon with a fully charged battery , and it would barely turn the motor over

[TownsendsFJR1300]

I've actually done 5 voltage drop tests now , but they have all been through the battery switch. I'm just not understanding how to make a physical connection between the battery and the starter if the battery is no longer hooked to my cables.

Am I to use jumper cables - I did this this afternoon with a fully charged battery , and it would barely turn the motor over

Yes battery cables. What was the voltage drop when CRANKING???

You've just 99% confirmed the battery is bad.. (or the starter suddenly failed/engine is seized-which we know turns /runs).
You can confirm this by having an independent auto parts store LOAD TEST IT..

Thank you, now we're getting somewhere.....

[DennisG01]

I've actually done 5 voltage drop tests now , but they have all been through the battery switch. I'm just not understanding how to make a physical connection between the battery and the starter if the battery is no longer hooked to my cables. Am I to use jumper cables - I did this this afternoon with a fully charged battery , and it would barely turn the motor over

OK, so you did have a failed battery switch (or dirty connections, anyways). But now you have a new switch? Voltage is one thing, but even a thin piece of wire can transfer 13V, yet when the power is called upon to start the motor, that wire will burn up because of the amount of amperage required can't flow through it. A corroded battery wire can do the same thing - as in, not allow enough juice to flow.

Do the voltage drop test on your existing wires. If you want to do a quick "proof of concept" that the problem is most likely your wires, use jumper cables from battery to motor.

As we discussed earlier, your earlier tests were not a "voltage drop test". It must done across a length of cable (or connection) and you should be applying a load... cranking the starter.

You mentioned you're not sure how to make a physical connection... then said you "did this this afternoon". Did you actually do the jumper cables thing? It's confusing. IF you did, right to your engine, was it a RECENTLY load tested/known good battery?

[gsdanno1]

I used my *****ing motor battery which was made in April of last year and has less than I hour of use . It was fully charged , 12.89 volts . This battery only has 750 marine cranking amps , but for this purpose I would think it would be enough . I wanted to use a battery I knew was good . I did not check voltage drop because all this time I thought I was looking for voltage drop in the boat's battery cables , and not the battery itself

[boscoe99]

I've actually done 5 voltage drop tests now , but they have all been through the battery switch. I'm just not understanding how to make a physical connection between the battery and the starter if the battery is no longer hooked to my cables. Am I to use jumper cables - I did this this afternoon with a fully charged battery , and it would barely turn the motor over

The battery needs to be connected to the motor via the motor's battery cables. Through the switch if you have one. Same with the motor side. Connect the volt meter probe to the post itself, not to the terminal at the end of the cable.

Anything that is installed between the battery and the motor needs to be voltage drop tested. It is like a chain. The system is only a good as the weakest link.

Make sure that the volt meter probe is connected to the battery post itself and not the battery cable terminal that is connected to the battery.

Things that individually or together with each other that can lead to excess voltage drop, which can causing a cranking problem.

Positive battery cable connection to the battery.
Battery cable itself.
Positive battery cable connection to the switch on both sides of the switch.
The switch itself.
Positive battery cable connection to the starter motor.

Negative battery cable connection to the battery.
Negative battery cable connection to the block.
Negative battery cable itself.

The battery can fail to maintain voltage under a load.

Here is a diagram that might help.

[TownsendsFJR1300]

I used my *****ing motor battery which was made in April of last year and has less than I hour of use . It was fully charged , 12.89 volts . This battery only has 750 marine cranking amps , but for this purpose I would think it would be enough . I wanted to use a battery I knew was good . I did not check voltage drop because all this time I thought I was looking for voltage drop in the boat's battery cables , and not the battery itself

It's been mentioned, way earlier, to check the battery.. However, it's not been properly load tested and still ISN'T.

***TEST THE BATTERY THAT IS ALLEGEDLY GOOD, WITH JUMPERS DIRECT TO THE BATTERY and ENGINE. (the battery you've been doing all your work with).***

That engine calls for a large, group 27 battery.

You need a solid, KNOWN GOOD battery, BEFORE other trouble shooting..

Once that's confirmed good(group 27), and the issue isn't resolved, follow the other trouble shooting methods..

[gsdanno1]

I will post all my results later this evening from my tests that I did today

[TownsendsFJR1300]

Unless you have a known good battery, the right size, fully charged, the results are useless.

(I won't bring it up anymore)..

Good luck...

[DennisG01]

Do you guys think his car battery would work good enough for a quick test? I mean, the spec that Yamaha calls for is probably for longevity's sake or "by the book"? A car battery should at least be good enough to do a quick spin-up to either nullify or prove the starter/engine from the equation?

[TownsendsFJR1300]

Do you guys think his car battery would work good enough for a quick test? I mean, the spec that Yamaha calls for is probably for longevity's sake or "baby the book"? A car battery should at least be good enough to do a quick spin-up to either nullify or prove the starter/engine from the equation?

Yes, it should.

The F150 engine is approx 2,300cc, the same size as most small cars..

He can actually bolt the F150 ENGINE CABLES direct to that car battery (to confirm the starter/engine is good). (I'm isolating the engine to rule out other issues-which I believe is the original batteries).

[gsdanno1]

Here are the results from my tests today . Both batteries were fully charged , batt switch was in the "both" position. Volt drops were done with my multimeter , new leads and alligator clips. Cranking times were 5 seconds






Battery 1 Battery 2
Initial voltage : 12.83 v 12.77 v
cranking : 11.68 v 11.77 v
volt drop + : 7.3 mv 9.0 mv
volt drop - : 5.4mv 5.8 mv
volt drop cranking +:1.4 v 1.4 v
volt drop cranking - :1.0 v 1.0


Next I took my leads and hooked from + power post to + starter post , then from - power post to - starter post



Battery 1 Battery 2

Initial voltage : 12.83 v 12.83 v
cranking : 11.0 v 11.2 v
voltage drop +: 4.0 mv 6.8 mv
voltage drop - : 2.8 mv 3.2 mv
volt drop cranking + :.85 v .90 v
volt drop cranking - : .52 v .60 v


I also removed my 5 month old *****ing motor battery with less than 1 hour run time , fully charged @ 12.89v , attached it to the starter , turned the switch and it would barely turn the motor . I will repeat this last test tomorrow with one of the batteries that I have been testing , as well as the battery from my truck . During the cranking procedures , there were times when the solenoid wasn't able to kick out the starter drive , but most times it did. I also noticed that I had to reverse leads on my meter depending on if I was going from the + side or the - side . Depending on time tomorrow , I may go from batt to batt switch and repeat , I will also try and get enough cable to take the switch out of the equation , and hook the field cable directly to the battery , and disconnect the other cables going to the switch as well

[panasonic]

So with the numbers you reported, there doesn't seem to be much voltage drop in the cables.

Am I correct in saying that you disconnected all the boats wiring from the starter, used a set of jumper cables, your new *****ing motor battery and connected this battery directly to the starter using the jumper cables?

I think the answer is YES to this question but I am asking so everyone is 100% clear about this. Please confirm.

If the answer is YES and the engine is still barely turning over, then I would suggest you have a starter motor problem.

Is the starter properly grounded to the engine block? Is there a ground cable from starter to the block?

[TownsendsFJR1300]

I also removed my 5 month old *****ing motor battery with less than 1 hour run time , fully charged @ 12.89v , attached it to the starter , turned the switch and it would barely turn the motor . I will repeat this last test tomorrow with one of the batteries that I have been testing , as well as the battery from my truck . During the cranking procedures , there were times when the solenoid wasn't able to kick out the starter drive , but most times it did. I also noticed that I had to reverse leads on my meter depending on if I was going from the + side or the - side . Depending on time tomorrow , I may go from batt to batt switch and repeat , I will also try and get enough cable to take the switch out of the equation , and hook the field cable directly to the battery , and disconnect the other cables going to the switch as well

The voltage drop with BOTH batteries looks good but your test with ONE battery and the voltage drop-CRANKING (which your going to do) should tell us something.

A good battery hooked directly to the ENGINE's pos and neg cables (no switches, long runs, etc) should tell the story and crank normally.

How many hours on the engine?


Too lazy to read back, but the engine has run since the rebuild correct?

Also, prior to the balancer failing, did the starter itself work fine-no issues?

Depending on what results you come up with(batteries pass load test-wired direct to engine), you may end up pulling the starter and checking that specifically... Wouldn't be the first time brushes wore out

[gsdanno1]

Starter has the 2 big cables coming from the console connected to it , 1 positive , 1 negative . No separate ground strap . I removed both of those cables as well as the wiring to the solenoid when I did the test . Engine has 881 hours , it was run from the ramp back to my lift , where it sits now . This has been an ongoing issue for some time . If I didn't mention it , starter spins very normal in the "both"position