Starter motor advice sought

Spike · Posted: Sat Jul 24, 2010 10:34 pm Post subject: Starter motor advice sought

Every so often my starter motor is acting up. Turn the key and the pinion gear will engage the fly wheel gear but will not turn the engine over. Usually it is one of 4 reasons, bad connections, bad battery, bad solinoid, or bad starter motor. Last time it happened 3 weeks ago I checked all the connections, they were good, bought a hydrometer and checked the batteries found 4 cells in the cranking battery not up to snuff so I replaced that battery the other battery checked out fine. No problems at all till today when I tried to start the engine to flush it out after a day of fishing. The engine has less than 200 total hours on it and the problem is so sporadic that I don't think it is the starter or solinoid.There is no binding in the engine it self as I can turn the fly wheel by hand and when it does catch the engine runs like a champ. The fly wheel gear is not burred, all the teeth look fine. Ideas? Thank you in advance
Chuck
Bootleg Hooch

Sea Wolf · Posted: Sun Jul 25, 2010 1:55 am Post subject:

Chuck-

With a new motor like that, it's improbable that you have one of the major components malfunctioning, and much more likely that you have a connection problem, especially if it's intermittent.

Most common is a weak ground. A weak ground will not work most relays, and is sometimes elusive. Check every connection between the battery and motor for clean contact and tightness. Wing nuts are weak tighteners for battery posts, and must be tightened with pliers, or better yet, replaced with real nuts!

Sometimes an apparent good ground (or positive terminal, especially) is intermittent when a battery post has a wet layer between the post and the surrounding lead connector. The wet layer, acting as a conductor, vaporizes as soon as the solenoid closes and the amperage jumps: this immediately interrupts the circuit and everything goes dead until the water condenses back from steam, and conductivity re-established.

Next, check the positive side out in the same way, this problem is really more common on that terminal.

Once you've done this, be ready for the next time it malfunctions.

There are two ways to approach finding the open circuit:

1. Use a VOM meter set on Ohms to jump each connection and seek out the open circuit. You'll get near zero resistance on good connections, the faulty one will show OL / open load. Do this when it malfunctions to find the open circuit.

2. Ground the negative lead (solidly!) with the negative battery terminal, then take the positive lead and start at the positive terminal and work away from it down the circuit looking for where the voltage feed is interrupted. You will have to have someone else help you to close the start circuit once your path gets to a switch or relay that has to be tested with the "start" circuit engaged. Again, this is to be done when the malfunctioning situation occurs.

If this process yields nothing, then we'll have to look at the components.

Good Luck, and be sure to tell us what you find!

Joe. Teeth

B~C · Posted: Sun Jul 25, 2010 9:25 am Post subject:

what Joe said....plus, you may have a bad spot on the starting motor commutator, when the starter stops spinning & a brush parks on that unlucky spot, no spinnage when you go to spin it up again...........which reminds me, I had a delicious spinnage salad last night with a hot bacon dressing

Salty · Posted: Sun Jul 25, 2010 9:39 am Post subject:

I agree with everything Joe said and I had a similar problem once that drove me crazy trying to find it. This was not on my boat but in a car. It turns out it was the key switch itself, just every once in a while it did not make a good internal connection. After the key switch was replaced the problem never came back. It acted just like a weak battery or bad ground.

Ted Osborne · Posted: Sun Jul 25, 2010 12:33 pm Post subject:

We recently had the exact same thing happen to one of our cars that Salty mentioned.

Stardust · Posted: Sun Jul 25, 2010 2:52 pm Post subject:

Had the same problem with my garden tractor recently. Replaced battery, solenoid, checked all connections all the cheap stuff. Finally put in a new starter and problem solved.
Todd

416rigby · Posted: Sun Jul 25, 2010 9:54 pm Post subject:

Prepare for sticker shock... if it is your starter, I hope it is cheaper than the one we had to replace on a Yamaha 250...780 bucks. That's not a typo...780 dollars.

Sea Wolf · Posted: Sun Jul 25, 2010 10:55 pm Post subject:

Lots of good information about starters, but I'd really be surprised if there's a problem there with under 200 hours on the motor, unless it's been used a lot with a really run down battery which increases the amperage with the low voltage and the resulting heating has affected the commutator's soldering

Joe. Teeth

Spike · Posted: Sun Jul 25, 2010 11:40 pm Post subject:

First I would like to thank Joe and all the others for their help. and now for an update. I have spent the last day and a half trying to get the problem to surface again.Must have gone out 30 times with the engine hot, cold, or in between no luck. The darned thing started right up every frigging time. Went and bought a multimeter to run the tests Joe advised. How do you test for a fault when every thing works perfect. Oh well I leave Wednesday for a five day fishing trip. Probably act up in the middle of the Strait of Juan de Fuca as a big old container ship comes barreling at me Wouldn't be fun if it wasn't a challenge
Chuck

C-Dawg · Posted: Mon Jul 26, 2010 1:33 pm Post subject:

Chuck,

You have a Merc on your boat, don't you? I've had something very similar to what you've described with my Merc. Same year boat, too. It's intermittent, so a real challenge to narrow down the fault.

What happens with mine is when I turn the key it seems like the battery is dead. Then I turn the key back and forth three or four times and then it starts. Weird.

Spike · Posted: Mon Jul 26, 2010 7:49 pm Post subject:

Rick
Hi How are you doing? Yes we share same year boat and make and model engine. How often has this happened to you? Your post has me thinking it is in the starter switch. Only I do get power to the starter motor, the pinion gear pops up and engages the fly wheel gear and that is where it stops. I am not afraid to do my own work on these things except when it comes to electrical stuff. But next time it happens I now have one more area to check. Are you doing Sekiu this year?
Chuck
Bootleg Hooch

Sea Wolf · Posted: Tue Jul 27, 2010 12:05 am Post subject:

C-Dawg · Posted: Tue Jul 27, 2010 12:22 am Post subject:

It only happens a few times a year. It happened again, though, last weekend at Neah Bay. I think I can hear the pinion gear engage, too, but it doesn't turn the motor. Then I turn the key off and on a few times and it starts. I wonder if the current is not passing from the solenoid to the starter motor.

I'm planning on doing Sekiu in September. I've heard the coho are already big for this time of year. Should be a good season.

Sea Wolf · Posted: Tue Jul 27, 2010 2:04 am Post subject:

Spike · Posted: Tue Jul 27, 2010 7:33 pm Post subject:

Joe
OK It might be time for you to hop on a plane headed north. Seems to be at least two boats in need of your expertise. I am not sure what I should do as the problem is so sporadic. Dollars to donuts it will not show up while the boat, or starter motor is sitting in someones shop. Thank you for your help.
Chuck
Bootleg Hooch