Yamaha Y Cop - F40 Outboard

[sottovento]

Hello, Merry Christmas to all.
Can anyone offer some advice. I have a tender on my yacht with a Yamaha F40 outboard. I have had the engine from new in 2013, it has always started very well. I have just re-joined my yacht after the Covid issues in March and the tender engine will not start and the engine was turning over slowly.
I noticed in the boat yard some Yamaha technicians working on another engine and asked for help. They came and connected their diagnostic computer to the engine and found no faults. There was no spark at the plugs and the plugs were dry. Through their computer they were able to produce a spark and the fuel pump was priming correctly. The technicians thought an issue with the kill switch or Y Cop immobiliser they suggested they would isolate the Y Cop but informed me that the engine would only run at 2500rpm if that was the problem. They isolated the Y Cop and it still would not start. The kill switch was also functioning correctly. The Yamaha technicians suggested the ECM was at fault.
I had a new ECM flown in and I swapped it out as I was told it was plug and play. No change the engine would not start.
I called another technician recommended by the boat yard. Within 10 minutes he found that the battery cables were corroded midway where the Yamaha cables were spliced to others that went to the battery box. I had the cables replaced and the engine started first time.
The problem I have now it will only rev to 2500rpm. How can I turn the Y-Cop back on? I have the key fobs and the Y Cop immobiliser seems to work as I get the one beep for on and two beeps for off.
What can I do?????

[boscoe99]

Was the old ECU reinstalled or is the new one still installed?

[sottovento]

Hi.
I installed the new ECM but then reinstalled the old ECM so the engine hours would be correct. New ECM back in the box.

[sottovento]

One more bit of information to add. I have just tried to start the outboard with the Y-Cop in the locked position via the immobilizer fob. It would not start. When I pressed the unlock button on the fob, the engine started.
So it looks like the I-Cop id working but the engine is running very lumpy and will not exceed 2500 rpm. Any suggestions?

[sottovento]

Further update. While the engine was running I removed the spark plug caps one by one starting at the top. Removed the top engine stalled. Removed middle engine stalled. Removed the bottom no change in the engine. I removed the plug and there appeared to be fuel. Could the Yamaha engineer turn off a coil when testing? He managed to bypass the ECU and create a spark from his laptop! Or have I a faulty coil or something else? Plugs all changed 3 hours ago. Engine done 100 hours in 8 years.

[99yam40]

I would find out what those techs did because they said they would do something that would limit the RPM

[sottovento]

New bit of information... I have changed the coils over middle to bottom and visa versa. Bottom cylinder still stalled when plug cap removed. So not the coil. It seems whatever controls the coil is not sending any electricity to the bottom cylinder. Still a mystery.

[sottovento]

I would find out what those techs did because they said they would do something that would limit the RPM

Now that is the problem. The Yamaha Techs were checking my engine in their own time. I didn't take their contact details so can hardly go to the Yamaha Dealer and ask who they were or what they did. I suppose that will be the last resort.

[panasonic]

Try swapping plugs around or using an old known good plug....it is possible that plug was dropped on the deck?

[99yam40]

New bit of information... I have changed the coils over middle to bottom and visa versa. Bottom cylinder still stalled when plug cap removed. So not the coil. It seems whatever controls the coil is not sending any electricity to the bottom cylinder. Still a mystery.

kind of strange, cause that is not what you said before.
"Removed the bottom no change in the engine."

[sottovento]

kind of strange, cause that is not what you said before.
"Removed the bottom no change in the engine."

Sorry if I was not clear. I meant I removed the bottom plug cap and the engine kept running on the other two cylinders. When the cap was removed from the top and middle cylinders the engine stopped as it can’t run on one.

[99yam40]

maybe Boscoe or someone else can tell us how that motor gets the proper signals to fire the plugs.

I know how 2 stokes work, but not the 4 stroke motors.

maybe there is a failsafe wire you can disconnect to make the motor run but not properly

[sottovento]

Hello,
A good day today. The problem was a corroded contact in the coil connector. Cleaned it with a paperclip and electrical contact cleaner and now works a treat. I will put those connectors on my maintenance schedule.
Thank you for your help.

[TownsendsFJR1300]

Hello,
A good day today. The problem was a corroded contact in the coil connector. Cleaned it with a paperclip and electrical contact cleaner and now works a treat. I will put those connectors on my maintenance schedule.
Thank you for your help.

Dielectric grease in that connector will stop future issues inside that connector...

A must, IMO...

[99yam40]

Hello,
A good day today. The problem was a corroded contact in the coil connector. Cleaned it with a paperclip and electrical contact cleaner and now works a treat. I will put those connectors on my maintenance schedule.
Thank you for your help.

but you swapped the coils and the problem did not move, how did that happen