8.1 Won't Crank Over When Engine is warm

D

Dasch Boat

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Jan 3, 2010
599
Long Island
Boat Info
2003 380 DA
Engines
8.1 Horizons ZF 63IV
V Drives
Have a recurring issue, my starboard engine will not crank when warm. Cold start is never an issue. After engine reaches operating temperature and I go to restart after being shut down for a few hours the fuel pump comes on but engine will not crank. So far I've done the following:
- swapped starter from port engine.
- replaced ignition switch at dash.
- replaced ignition solenoid 3 times.
- replaced 50 amp circuit breaker.
- disconnected 10 pin connector in wiring harness, cleaned female side (not visibly corroded), opened male ends of connector and reassembled with dielectric grease.
Same result, starts when cold, won't crank when warm. I have started the engine by shorting out the solenoid so I can return to home port. Anyone else have this issue or any ideas on what I'm missing?
 
I've had a similar issue, with two different causes.

For one, I thought it was a bad dash switch but it turned out to be the connector that attaches to the back of the dash switch. Every once in a while it still happens, and I will have to reach up and gently move the wiring to the stbd switch in order for it to engage the starter.

The other issue had to do with the neutral safety thinking it was not in neutral, but that was happening hot or cold.
 
Sounds like your not getting the 12v. on the small r/y wire that comes from the ign. switch that triggers the slave solonoid. Make sure the slave has a good ground.
 
scoflaw said:
Sounds like your not getting the 12v. on the small r/y wire that comes from the ign. switch that triggers the slave solonoid. Make sure the slave has a good ground.
Click to expand...
Thanks for the advice, are you referring to the starter or ignition solenoid ground?
 
Slave ground. Next time it happens jump a wire from the + battery terminal to the smaller r/y terminal on the slave. That should narrow things down for you.
 
I had same problem on a 33 dancer. Neutral safety switch. Worked fine when cold but hung up when hot. Easy to check once I realized that might be the cause. Good luck
 
Crankshaft sensor. Swap between engines to see if problem follows. Had exactly the same issue. The problem results from the magnet on the tip of the sensor which is nearly touching the crank shaft cracks. When it heats up it moves just enough so it can no longer record the movement of the crankshalf turning. The sensor is located on top of the bell housing held by one bolt. Easy swap. When you put it back in besure it seats in with a slight click. But don't over push it down. Otherwise the tip will touch and ride on the crank. You'll hear it rubbing if it's touching when engine running. Just readjust up ever so slightly then tighten.
 
LG111 said:
Crankshaft sensor. Swap between engines to see if problem follows. Had exactly the same issue. The problem results from the magnet on the tip of the sensor which is nearly touching the crank shaft cracks. When it heats up it moves just enough so it can no longer record the movement of the crankshalf turning. The sensor is located on top of the bell housing held by one bolt. Easy swap. When you put it back in besure it seats in with a slight click. But don't over push it down. Otherwise the tip will touch and ride on the crank. You'll hear it rubbing if it's touching when engine running. Just readjust up ever so slightly then tighten.
Click to expand...

The sensor being damaged would cause the engine to not crank over at all?
 
Dasch Boat said:
The sensor being damaged would cause the engine to not crank over at all?
Click to expand...
Ah, sorry I miss understood. Not cranking, like it's locked? Wont turn but starter trys? Sounds odd. Can you describe more about what is working when you turn the key?

Theory.... Have you checked the oil for water intrusion? Milky color. Warm after shutdown the manifold drains water into a cylinder via a internal crack and locks the engine. By the time it's cold, the water slips past the rings and no hydrolic locking. It only takes a small amount of water to lock up an engine.

Next time it does this and won't crank. Try pulling all the plugs and see if she turns over. If she does you found the problem.
 
Engine runs fine when started cold so is not hydro-locked, issue is will not restart when warmed up. If you go back to my original post I listed the symptoms.
 
If you can crank it by jumping the slave you missing the power from the key in the "start" position to provide power to the slave.
From the key switch thru the neutral safety switch in the control box to the slave solenoid to operate the main solenoid on the starter
 
Bt Doctur said:
If you can crank it by jumping the slave you missing the power from the key in the "start" position to provide power to the slave.
From the key switch thru the neutral safety switch in the control box to the slave solenoid to operate the main solenoid on the starter
Click to expand...

Okay but why is it intermittent? Starts fine when it's cold but won't crank when you try to restart once it has been running at operating temperature.
 
Look under the dash for 2 yellow/red wires cut and connect them together for testing .
Usually there in a black rubber covering like round lamp cord. you want the wires from the ign side not the control box side. But know that doing this it WILL START IN GEAR
 
Bt Doctur said:
Look under the dash for 2 yellow/red wires cut and connect them together for testing .
Usually there in a black rubber covering like round lamp cord. you want the wires from the ign side not the control box side. But know that doing this it WILL START IN GEAR
Click to expand...

Thanks Doc, I'm familiar with the yellow wires with red tracers, will this tell me that the rocker switch is bad? I have swapped that out already. I'm leaning towards swapping the neutral safety switches from port to starboard as a test when I get out to the boat tomorrow, what do you think?
 
I had a similar problem years ago. Turned out to be a corroded main ground wire on the engine block. Once taken off, cleaned and reinstalled it's never been a problem since. It wasn't due to a warm engine, but that's when it would happen. It was from sitting for a period of time with the stereo on before re-starting. Apparently the batteries were weak enough that the stereo drained the batteries just enough that the current couldn't bridge the corrosion with enough power to start the engine. It would always start cold at the dock, but the batteries were at their best just coming off the charging system. Worth a try.
 
Dasch Boat said:
Thanks Doc, I'm familiar with the yellow wires with red tracers, will this tell me that the rocker switch is bad? I have swapped that out already.
Click to expand...

Could be the wiring and/or the connector if the switch is fine?
 
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