Merc 260 w/ alpha 1 won't crank.

[Tiwaz]

Ok so its merc 260 w/thunderbolt IV ignition that won't crank all I get is a single click from the starter solenoid. Friday afternoon I tried to start it and it cranked for about 10 sec. then nothing just the click. I have read and searched past threads and after following a great trouble shooting guide from Don S. I think I have it narrowed down to the slave solenoid but I am second guessing my diagnosis.

When checking the power into the slave its good but when checking the output with a test light it just flashes and dies (this is when I get the single click from the starter). The reason that I am not sure is if I try and jump across the slave the starter doesn't crank (it should right?). I have checked all of my battery cables/terminals and they are good.

Any help is appreciated.

 

[Maclin]

Re: Merc 260 w/ alpha 1 won't crank.

I would have the battery load tested. I have had them charge OK but not really have the reserves to crank more than 10-15 seconds total.

 

[NHGuy]

Re: Merc 260 w/ alpha 1 won't crank.

So the output from the solenoid is poor. Clean up the contacts, all of them including grounds. And as Mac said verify your battery cranking power with a load test.

 

[Bt Doctur]

Re: Merc 260 w/ alpha 1 won't crank.

sounds like bad battery, battery cables, cable connections

 

[achris]

Re: Merc 260 w/ alpha 1 won't crank.

Do a volt drop check from the battery to the starter motor on the red leads, and from the battery to the frame of the starter motor on the negative leads. If you have a poor connection it would show up exactly the way you're seeing.

Chris.....

 

[Tiwaz]

Re: Merc 260 w/ alpha 1 won't crank.

Alright, I'll get the batteries load tested and do the voltage drop test and see what happens then. Thanks for the pointers thus far.

 

[Tiwaz]

Re: Merc 260 w/ alpha 1 won't crank.

So the batteries have been load tested and they are good. So does that mean I am back to the solenoid?

 

[dubs283]

Re: Merc 260 w/ alpha 1 won't crank.

try jumping the starter solenoid, if it still clicks, the starter motor is most likely the culprit

 

[Bt Doctur]

Re: Merc 260 w/ alpha 1 won't crank.

Not yet. If you know how to jump the solenoid, do that first. motor should spin normally. If not the battery, battery cables, cable connections, starter are bad.
if the motor spins, locate the slave solenoid and short the 2 larger lugs, this should spin the motor. report findings.
using a jumper from the battery, touch the small lug with the yellow /red wire. solenoid should operate and spin motor, report back

 

[dubs283]

Re: Merc 260 w/ alpha 1 won't crank.

locate the slave solenoid and short the 2 larger lugs, this should spin the motor.

sounds like the op already tried that back in post #1 doc

think thats why folks were leaning towards the battery/cable issue

 

[Tiwaz]

Re: Merc 260 w/ alpha 1 won't crank.

OK so for now I will fall back to what I did last week, before I pulled the batteries to get them tested. When I tried jumping the slave solenoid nothing happened just a click from the starter solenoid. I had checked for power at the starter and had checked the cables with a test light, I can test with a meter if you think it makes a difference. I am going to go out to the boat tomorrow and I am looking for suggestions.

Thanks,

 

[dubs283]

Re: Merc 260 w/ alpha 1 won't crank.

When I tried jumping the slave solenoid nothing happened just a click from the starter solenoid. I had checked for power at the starter and had checked the cables with a test light, I can test with a meter if you think it makes a difference

meter will give a definite number, one to compare with the battery voltage - also you can do a volt drop test with your meter, that will show if there is mass resistance in the system

try jumping the starter solenoid, you say it clicks when you jump the slave solenoid, this would be your next test - if it clicks, voltage is okay, and the starter does not spin, then the starter motor is the problem

 

[Bt Doctur]

Re: Merc 260 w/ alpha 1 won't crank.

need to start with good high current connections. jumping at the starters solenoid tells you that the connections(battery posts, wing nuts, cables, cable connections are capable of carrying 300 amps.)
Main system power is supplied at the starter lug either directly or thru a fuse block bolted to the starter lug. From there it goes thru the 50a breaker ,thru the engine harness plug and then to the dash.
Shorting the slave lugs verifies sufficient current at the slave to trip the solenoid on the starter.
Take battery cable jumpers with you too

 

[Baylinerxxx]

Re: Merc 260 w/ alpha 1 won't crank.

I had same issue and finally took out starter yesterday to have checked at auto parts. It was frozen. I hope this solves issue today when new starter comes in.