Peculiar engine starting issue

[DennisG01]

Just to double check, you did both pos and neg, right?

OK, well it was at least worth a shot. Eliminating variables is still a good thing. Maybe you've already done this, but just in case...With the hood off, take a look at the wires coming into the engine from the rigging tube - looking for anything that is "stretching" as the engine turns. Just go through everything with a fine tooth comb, looking closely at the wires - both where they go into the there connector and where the attach.

Can you post a pic of the rigging tube? Just wondering if it's too tight.

What other wires go from the boat to the engine via the rigging tube? They could be possible culprits.

[99yam40]

Thank you for the added suggestion. I spent 4 hours this afternoon chasing this problem. Unseated every wire I could find and snipped a bunch of zip-ties hoping to find the "culprit" wire. Nothing changed the situation. I just went back out and ran the battery jumper test again per your suggestion of leaving the existing battery cables attached. No luck, no change. I actually shot a video today of the problem but wasn't able to get it uploaded to this forum. I learned one additional thing today ... when the steering wheel is spun far right it literally has to be to the steering stop-point or the starter will not engage. When the steering cable makes a "thunk" at the end of the travel, the motor will start. Otherwise, no life in the starter.

still you have not put a meter on the power heading to the key switch or out of it.
also check at the start relay from the key switch.
those will give some idea of what is going on

[Frankh27]

I'm here to report that I was finally able to solve the engine start issue. Yes I am having a cold beer! It was the 10-pin main harness cable. If I straightened the motor to center line of boat and tried the key switch, no response from the starter. But when I bent the 10-pin harness about 30 degrees to the right (2" from where it entered the motor cowling) it cranked. I had my wife on the ignition key and I was able to duplicate the scenario every time. It had to be bent at the same spot each time to make the circuit work. So i am headed to Central Marine in the morning to get a new 10-pin harness. Y'all were very helpful and supportive and I thank you for that! Hopefully someone else will benefit from this thread and not waste a gorgeous Sunday afternoon troubleshooting a similar problem.

[DennisG01]

That's great! So do you think it was simply due to everything being installed without enough flex/bend in the rigging tube?

And... messing 'round with boats is NEVER a waste of a good afternoon!

[99yam40]

I would think a broken wire in the harness is what the problem was/is

[99yam40]

also I do not know what kind of controls you have, but some have the 10 pin hooked in with the con*****er.
you can get a new harness, but may need to take the con*****er apart to hook it up inside of there.
I hope that is not needed, but just wanted to warn you.


you could split the jacket/insulation of the harness and locate the bad wire back by the motor, and repair it instead of replacing the whole thing

[HarrisonDawgs]

I agree with broken wire in harness somewhere. Either that or possibly a bent or corroded pin at plug. Glad you figured it out!
Almost exactly what I had years ago with my Mercury XR4

[Frankh27]

I can now report in detail, no more ghosts! I cut the first 3 feet off the old harness and stripped the thick black rubber cover. The entire bundle of wires were crimped in a zig-zag pattern where the harness passes through the engine cowling rubber block. See pics. So the harness was out of position (not in its respective groove in the block) when the metal clamp was torqued down. None of the wires' insulation was broken, but I found that the brown wire (neutral switch from throttle) had all the copper strands broken. So now it all makes sense. Turn the ignition key, the motor "thinks" the throttle is not in neutral so no signal to the starter solenoid. Bend the wire just right (steering all the way right) and by pure luck the brown wire bends to the point where the copper wires inside make contact and the starter solenoid receives the go-ahead signal for the starter to spin. BTW there was absolutely no corrosion on the pins or the wires. And the crimped wires could not be detected by simply feeling the outside of the black rubber cover. Hopefully this episode will help others in the future! Thanks again for all the support from all ))))

[DennisG01]

That's great that you finally found the problem! I bet that's a HUGE load off your mind!

But... you need to share this with the person that installed both your engines!!!

[Frankh27]

That's an interesting thought. The boats were years apart and both were rigged by the original boat dealer (no re-powers). I'm sure that the Tidewater harness was never tampered/serviced. It had 30 hrs on it when I bought it in 2015. The Hurricane is a 2000 year and it is the original engine, I've had it for years but who knows what it's been through over it's service life. The part that still baffles me is that I experienced this problem twice and no one else has had the problem. Regardless, yes, I am very relieved to have uncovered and corrected this ghost-problem. I'm an old gas turbine mechanical engineer and spent many years testing military engines (F-15 & F-16). We always said, find the problem and we can fix it. Guess that will always hold true!

[99yam40]

so, did you buy a new harness?
or did you fix that one wire?

[Frankh27]

I replaced the harness with a new one. Cost for the new harness at the Yamaha dealer was around $100. I could have spliced new wire segments in place of the crimped section, but decided to go new instead. Replacing the harness was only a 2 or 3 hour task. Now everything is good for another 10 years hopefully.

[zenoahphobic]

So we take it as careless installation, albeit by the same dealer many years apart.

[Frankh27]

Yes careless or improper installation is what I would boil it down to, but to clarify, it was done by two different dealers/riggers: boat #1 was a 2000 Godfrey Hurricane with a 2000 C115; boat #2 was a 2013 Tidewater with an F150.

When i installed the new harness, I wrestled with getting the cables & wires & fuel line in the correct channels of the rubber block ... so I can definitely see how someone could get impatient or rushed and mis-assemble the bundle. The top surface of that rubber block lays nice and flat when everything is channeled properly so that the metal clamp with the two bolts holds the rubber block in place. If the bundle is not channeled properly, the metal clamp becomes a "compression device" on the rubber block and this is when wires get crimped. I don't have the Yamaha service manual, but I wonder if there's a cautionary-note warning the installer to verify the bundle is seated properly prior to torquing down the metal clamp.