Engine won't start

[philminotti]

Was out for a drive in the Cobra yesterday (Pond 482).  No issues at all.  Went to start it this am, and the starter would only crank the engine about a quarter turn.  Thinking weak battery, I attempted a jump and no difference.  Again, the solenoid engages and the starter turns, with difficulty, about a quarter of one crank revolution.  It's not a hot timing issue because I've never had any problem in the past, hot or cold.

Fearing distaster, I put a half inch breaker bar on the crank nut and was able to fully turn the engine over by hand at least two full revolutions.  Obviously it wasn't easy, but it turned, so I'm confident it's not seized.  Also, I've had no oil pressure problems.

Before assuming a starter failure, anything else to check?  It's a RobbMc starter.  Due to a pretty good rear main leak, oil has been getting spun up onto the nose of the starter.  Don't know if that means anything to anyone.  Just thinking out loud, maybe oil has gotten on the solenoid contacts and limited the current to the starter motor?

[Nightmist66]

The oil on the contacts should not be a big issue, corrosion is a big problem. Maybe a loose contact? Are the cables tight on the starter? Does the RobbMc starter have the built-in solenoid and does it also have a nose cone? For some reason I think I remember hearing someone having a problem breaking the nose cone on one. When you try to crank the engine, does the cable get warm/hot? If so, you have a resistance problem with the cable itself or a connection. I don't think you would have a problem with not enough grunt from a mini/gear reduction starter. We have a factory Ford starter on the racer with 14:1 and no problems.

[Drew Pojedinec]

1. Battery voltage is 12+  ?
2. Check voltage at start solenoid.  Use the engine block ground if possible
3. Check cranking voltage (will require a helper).  Checking at the starter itself would be cool, but might be an issue with space so trying it on the output of the start solenoid would work.

[philminotti]

Thanks for the replies.  I'll look at my connections and make some voltage measurements tonight.

[shady]

my money is on a shorted batt.

[ScotiaFE]

I'd bump the solenoid.

[Lenz]

2x on the solenoid bump.  Once you verify the battery and connections you'll definitely narrow your search based upon the outcome.

[mb198]

Try disconnecting the battery terminals and cleaning posts and terminals with a battery cleaning tool or sand paper.

[philminotti]

Just a follow-up to my cranking issue...it was the starter.  A new gen 2 Robbmc starter is in place and working well.  The gen 2 Robbmc starter seems to spin my motor substantially quicker than my gen 1 unit.  As for the old starter, I'm sending it back to robbmc for diagnosis and repair.  If I had to guess, I'd say there's a broken tooth or seized bearing in the gear reduction assembly.

[jayb]

Thanks for the follow-up, Phil!  Its nice to know what actually happened, and what the solution is - Jay

[turbohunter]

Hmm
Thought those deals where pretty much bullet proof.
Love to hear what they have to say after diagnosis.

[jayb]

I had one fail too, a few years back.  There is a one-way clutch in the mechanism that gave up on mine.  When I contacted Robb about it he said he'd gotten a batch of defective clutches, and a few starters went out with them before he figured it out.  Just my luck    Anyway, he fixed it at no charge; really good service from him.

[gtxpress]

Check and make sure solenoid is got a good ground where it mounts.  To check just run a wire from the mounting area to the block.  Good luck.
GT