How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Charles Your Own Question
Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3711
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
Type Your Boat Question Here...
Charles is online now
A new question is answered every 9 seconds

I have a Yamaha osx150 saltwater series EFI. When motor is

Customer Question

I have a Yamaha osx150 saltwater series EFI. When motor is on plane works fine full speed. When I hit waves the motor rpms go down to zero and shuts off. I turn it back on it always starts. I replaced bulb, lower and upper mech pumps, filters, I don't think it's a fuel problem. I am stomped.
Submitted: 1 year ago.
Category: Boat
Expert:  Charles replied 1 year ago.

Hello, my name is***** will assist you.

The issue you are having is definatally electrical in nature. Start under the dash at the key switch and insect all wiring that is going to the engine for any loose wires. If you cannot locate any there, move to the engine and inspect all of the plug ins on the ECU and the plug where the wires come from the boat going to the engine. You should locate either a loose connection or a broken wire.

Customer: replied 1 year ago.
Charles just came back from the water and the boat was doing the same thing. However now it made a beeping sound like when the wrist band cut off near the key for the ignition. I got the boat out of the water pulled the two wires from the safety wrist cutoff. And it started right up strong. I am thinking as I hit rough water that kill switch moves around and cuts the motor off. I am going to try it on the water tommorrow. I checked every other wire, spark plugs etc.. Does this sound like a possibility?
Expert:  Charles replied 1 year ago.

Yes, that is a very good possibly that the switch is bad.

Customer: replied 1 year ago.
If it runs good tomorrow and I do not replace the kill switch will it affect anything else?
Expert:  Charles replied 12 months ago.

No. the switch is plug and play.

Customer: replied 12 months ago.
It wasn't that. I traced the wire all the way to engine. Found one wire connection that was loose and basically not connected. If I recall it was a yellow wire which I believe goes to the Cdi according to the service manual. Going out again in the water tomorrow to see how it runs on hole shot to plane.
Expert:  Charles replied 12 months ago.

The yellow wire would also do it. Any lose wire on the engine or in the dash can.

Customer: replied 12 months ago.
Put in the water for third time same thing. I give up. Took it to mechanic today he thinks it might be fuel injectors I hope not.
Expert:  Charles replied 12 months ago.

I dont think it would be the injectors, you are losing key power somehow.

Related Boat Questions