Turn key off - does not stop engine

[JetTech]

I was getting my 212 SS ready for the boating season at home. I started the port engine, turned on the flush hose, ran the engine, turned off water, shut off engine. I did the same to the starboard engine except when I turned the key to OFF, nothing changed (the engine kept running). I pulled the kill switch and the engine still ran. The best solution I found to stop the engine was to turn the battery switch to OFF.
I found many people asking this same question but no answers ( it is not dieseling or a bad key switch)
Any answers or debug tests?

 

[Scottintexas]

glad to have you on board,

How long have you owned your boat?
have you ever read the hours or checked the ECU with a YDS?

I've not heard anyone here have this problem before,

just trying to trouble shoot, very odd the lanyard didn't stop the engine, I would also try lifting the cleanout hatch to see if that stops it, just to isolate it even further (and of course try it with the good engine also),

doesn't the safety lanyard feed back into the key ??

How did you test the "off" portion of the key switch?

 

[Julian]

Very strange and the first time I've heard this.

I found many people asking this same question but no answers

Where did you find these people?

Are you the only owner of the boat? I wonder if a prior owner rewired the boat to overcome all the safety switches!!!

 

[JetTech]

I bought the boat last August as a project. It was in bad shape from salt water and abuse. The repairs that I made are too long to list. The key shut off problem just started yesterday, after starting for the first time from winter storage. There are other forums that ask about the same problem. I switched the 6 pin connectors between port and starboard keys and the problem followed the engine.
I did take the computers apart last November. Also, the boat battery was low so I jumped it from the car.
Any suggestions on wires to test or part failure that could cause this?

 

[Scottintexas]

when you "took apart the computers",
what symptoms made you take them apart?
what exactly did you take apart?
what did you do to them while apart?
has the boat ran correctly since you reinstalled the computers?

I would have thought this was a wiring issue near the key but with the computer issue common sense says that's the first place to look for the problem,

attached is the wiring diagram,

 

[Julian]

When were the spark plugs changed? Always my first go to when these engines act up!

Then I'd be pulling the lanyard and clean out tray kill switches and confirming they are all still wired in, check the connections, clean them and retry.

 

[JetTech]

Reply to ScottinTexas
I took the computers apart because of three bad fuse holders. I latter realized that the they were intended to be nonfunctional.
I was just speaking with someone who reminded me that I replaced the starter relays at that time. He had heard that sometimes these relays stick "open". I will examine the relays today.
Thank you for the wiring diagram.
I bought the complete service manual last September, after changing the spark plugs for the first time. One plug was so corroded it snapped off leaving just the thread in the engine. I had to pull the engine head and have the plug drilled out.

 

[Julian]

I would think tha if the starter relays were stuck on, you'd hear the starter impacting in the engine bay....but perhaps you didn't have the hatch open? Easy enough to test.

Did you mess with the key switches at all in this process?

This thread is the opposite of what you are facing, but might be helpful in reverse diagnosing why the engine won't stop when these are triggered:
https://jetboaters.net/threads/engi...engine-codes-and-battery-voltage-states.1835/

 

[JetTech]

A Yamaha mechanic suggested that a bad starter relay could cause my problem (he had seen it before). I opened up the computer (ECM box) and replaced the relay with another one. Same problem - switch to OFF does not stop engine.
Any other suggestions while I have the ECM open?

 

[JetTech]

Also, the kill switches, at the throttle and the clean out hatch, stop the port engine but not the bad starboard engine.
I disconnected all the instrument panel wiring that I had worked on this winter and checked the fuses at the battery.

 

[Scottintexas]

it's time to get multimeter out and start testing, I would start with the key switch and would guess your problem is going to be in plug #5 in the diagram above,

Your better off taking it to a shop than blindly buying parts for it,

 

[JetTech]

Reply to Scottintexas:

Excellent suggestions.

About the starter relay - at the end of last year I had a bad starter relay and replaced two of them(one on each engine). I saved the old good one and used it to test a potential defect in the new starter relay.

This was my day to buy new batteries. I got a new marine battery for the boat and 2 AAA batteries for my multimeter.

*Question about the #5 plug on the diagram - does that show Black and White wires are grounded when switch is OFF?
So I can do a continuity test between Black and White? The same status is true when the Lanyard is pulled and the cleanout hatch is open?

 

[bronze_10]

U could swap the ecu with the other engine and see what happens..

 

[JetTech]

I think an ECU swap would be a lot of work, so I will save that for latter.

I found on another forum - " I've also heard it could be the infamous white wire that could be preventing it from turning off. I'll let ya'll know. " He found a broken white wire in the harness. Fixing the wire solved that problem.

Multimeter testing today!

 

[bronze_10]

Oh it is a lot of work.... ask me how I know!

 

[JetTech]

I took apart the clean out hatch kill switches. They each have four wires 1 black, 1 white and 2 brown. I was able to get continuity with the matching colored wires on the key switch port (good) harness. The starboard (bad) key harness had continuity with multiple wires at the rear hatch kill switch wires.

I got dark so I will do more testing tomorrow.

 

[JetTech]

What would be the symptoms if one throttle had the Neutral Safety Switch always closed (brown wire shorted)????