Intermittent Starting Problem

Sometimes my starboard Cummins 370 hp (mechanical) turns over and sometimes it does not. Just clicks and acts like a dead battery. Sometimes I move the shifter back and forth all the way to exercise the neutral safety switch and sometimes it rolls over and sometimes it does not. If not, I move all 4 battery (8D) switches to ALL and sometimes there is joy and sometimes not. If not, I press the parallel switch on the bridge and sometimes it rolls over and sometimes not. Today I did all the above and nothing worked. Then I tried it without any extra measures and it started. Go figure.

Until today one of the above procedures has always worked but I am stumped as to the cause. The 8D AGM battery is only 4 months old. It takes a charge well and unless the boat is not run for a day or two the starter engages as if nothing has ever been wrong.

This happened when I bought the boat in late July and all assumed it was the battery...so it was replaced.

Intermittent problems are hell. I wish things would just break and get it over with.

Any ideas?

well I guess it is now trial and error I love chasing the ghost. I would start by checking the voltage at the battery and then work your way inward toward the starter also check your start button I had a bad one in my engine room with similar symptoms sometimes it would work and sometimes it wouldn't. always works now that I changed it.

Check all terminals for tightness and cleanliness. At that batteries, at the battery switches, and at the starter.

Remove the fastener that attaches the ground cable to the engine block. Clean the cable and the area of the block where it attaches.

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Originally Posted by rmatt

Remove the fastener that attaches the ground cable to the engine block. Clean the cable and the area of the block where it attaches.

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X2. No ground means no juice.

Replace and adjust the neutral safety switch.

Quote:

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Originally Posted by kelpy

Replace and adjust the neutral safety switch.

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To check the neutral safety switch, just bypass it until you can rule it out.

I do not doubt the wisdom of the forum, and would simply add that I had a similar problem corrected by cleaning ALL negative ground wires and terminals.
Another 'same' problem was solved by a new starter switch at the upper helm.
Best of luck, you will overcome!
Sailor John

I'll pass along my similar problem from a year ago. I went through new 8D's, new wire ends, rebuilt starter etc. A marine electrician changed the wire ends a second time to a better quality, AND changed the battery selecter switch. No more issues after more than 3000 miles operation. In my case I could watch the voltage drop at the bridge volt meters. More than a 1.5V drop when starting seems to be trouble.... a simple system condition test.

Bobk

Electrical problems are, as noted in several posts above, are usually connection-type issues. I suspect that cleaning all the appropriate connections will solve the problem.

A voltage drop test is, IMO, the most useful test for determining the condition of the wiring/connections/switches between the power source and a component and/or isolating the problem. If you are not familiar with the procedure (you'll need a multimeter/voltmeter), you can do an internet search for "Voltage drop test" and find many tutorials. Many of the tests you will find will be oriented toward 12V auto starting systems but the process is identical regardless of what kind of component/voltage you are testing.

I had the same thing happen, It was a grounding issue. as posted, no ground no power.... I had to take them off and clean them up . I was told it was the starter by an expert.....turned out the starter fixed itself when I cleaned up the grounds..... Amazing how that happed.....I guess I just have a magical boat....Watch out for the experts......Good luck

I've had similar problems over the years.

The first thing I`d try would be to tap the starter with a hammer. If it start's it's the starter.

Other times the solution was discovered using the above techniques.

Will

I had very similar problem a few years back with 300 h.p. cummins. The main battery disconnect switch had failed. There is a spring in the quest switches that puts tension on the contacts. The plastic behind the knob fails thus relieving a lot of the tension from the compressed spring. Have someone attempt to start the engine with someone pushing hard on the knob that turns the power on and off. If engine starts replace the switch, if not carry on with other suggestions. It could be a weak connection anywhere between the battery and the starter. The switch will pass voltage if it is bad, but not always enough amperage to turn over the engine. Good Luck, Steve

What they said. I'd clean and tighten all the wiring connections and cables first, and then look at the solenoid and the battery switches. And the NSS, too.

Checking, cleaning and replacing connectors, especially crimp on connectors as suggested several times will most likely solve your problem. Take note that when one of these connections fail, you can be pretty sure others will soon follow. Being that the solenoid activates your problem is most likely one of the large wires or connectors causing the problem.

The problem is called a high resisance connection, it will often lead one astray in the troubleshooting process because it will show voltage is good with no load on the circuit, when the load is applied the voltage will drop due to the high resistance connection. Have someone try starting the engine while you are reading the voltage, start at the starter and work back toward the source. Don't overlook the possibility that the start solenoid is bad. The starter is easily checked by shorting the heavy contacts together, this will make the started energize, if you don't know how to do this get someone who does to help you. Good luck

This article appears quite often, might help you find the issue if it's in the wiring.

http://www.engine-light-help.com/voltage-drop.html

Thanks for all the good advice.

I have checked everything that I can reach so I am going to hire a boat electrician.

It is going to take a smaller and more flexible person than me to go outboard of the engine to get to the relay, starter and solinoids.

The boat electrician came and found good voltage to the starter. Lots of clicking and clunking but no cranking. He does not do mechanical work but said that the starter must come out.

The bad news is that it is in a place with very tight access...outboard of the engine at the back. The electrician could get his tester on the starter but said that even a mechanic will have a hard time getting it out without pulling the entire galley to get access to a hatch over the engine.

I have called my regular mechanic.