intermittent Engine Cutting Out

[stu1]

Hi, I am wondering if you could help me and my mercury mechanic in trying to fix an intermittent problem.

My boat cuts out on me at irregular, obscure no pattern time. Its as if someone has gently turned the ignition key to off and when I restart the boat, it is as if nothing had ever happened. I can run it for 30 mins on idle one day then the next day it will cut off after 5/10 minutes and restart no problem. When running the boat, I can go on the plane no problem, no lack of power, perform up to 5k rpm then come off the plane and run at under 1k rpm it will or will not without any warning cut out. It has now become a major problem as my mooring is on a river which can run at times fast, so you can imagine my boat cutting out at the wrong time would be dangerous to everyone. The local mercury mechanic has done the following:

• Regularly Serviced.
  
  
• Replaced IAC Valve.
  
  
• Replaced Fuel Pump / Regulator kit.
  
  
• Replaced Crank Sensor.
  
  
• Replaced Coil.
  
  
• Cleaned Out Fuel Tank and Fuel System
  
  
• Checked all wires for corrosion and being loose.
  
  
  Any help would be much appreciated as we are at a loss.
  
  
  Kind Regards
  
  
  Stuart Arthur
  

 

[Espos4]

What happens when you wiggle the ignition key?

does it stall?

 

[stu1]

Not tried that??? I will try that tomorrow.

 

[Espos4]

And not just the key, give everything the “wiggle test”, especially the wiring around the distributor.

 

[Greg Lions]

Do your gauges do anything ( drop to zero/blank out ) when the issue occurs? If so could be low voltage - check/replace your alternator and or batteries.

 

[Searay Chuck]

I would after you have checked for loose connections especially the main harness to the engine, check and replace the ignition module inside the distributor. I know it has been said that they either work or they don't but I have had this issue before as well as another person chasing the same problem and by replacing the module it solved the problem each time.

 

[Strecker25]

Is it an alpha outdrive?

Another member recommended I replace the shift interrupter switch as I had the same thing happen the other day on our port motor. Admittedly, I also replaced the alternator and coil because they were suspect but the gauges were bouncing like it was a very brief stall and then recovering. The thought was the interrupter switch was wacking out and causing the issue. Boat ran great after those 3 parts.