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2011 60hp 4 stroke runs well to half throttle then quits if accerated to full

W

worains

New member
Engines cranks and idles perfect. Runs to half speed perfect. If you advance the throtte to full, it cuts off. Sometimes you can recover by reducing the throttle immediately and the engine will continue to idle. Or, you can just crank back up easily.

Replaced fuel filter. Hooked up test tank with fresh gas, new fuel hose and bulb. Primed fuel filter, cranked perfect as always. Ran boat out up to half throttle and when I advanced the throttle, the engine cut out. Did this repeated times.

Here's where it gets tricky. It seems that under a greater load then half throttle, the engine suddenly cuts out. Wanting to test again without taking the boat out of dock, I was able to secure the boat in the dock and run the throttle to full and no issue. The engine ran as expected. No issues when tested in dock. Immediately took boat out in the open water and the boat cuts out when going over half throttle.

Thoughts?

Thank you for your consideration!

Bill
 
You may have a short in the control box. Your kill switch circuit, or OFF switch position ground that kills triggers when you turn the key to OFF wiring may be chafing on your throttle handle. Open it up and have a look. My first guess was fuel filter but you changed that. You didn't happen to cut the old one open and have a look inside did you?

Since you changed fuel tanks I assume that meant hose between the tank and engine. That eliminated an accumulation of varnish.....course if you had a varnish problem you would have tan chips in that old fuel filter.
 
If you are using the Commander 2000 or 3000 standard Mercury/Quicksilver single lever control with the 8 pin engine connector, the engine kill terminal is Pin 1 a Black wire with yellow stripe. Looking at the connector from the engine wiring harness, not engine side, hold it so that the blank area is due South...for a dimension. Pin 1 will be first pin on the right and looking around behind the plug you will see a black wire with yellow stripe.

To kill the engine the triggers are grounded in the control box ignition switch from this wire being connected to Pin 4 which is the black ground wire.

Unplug your wiring harness from your engine wiring harness. Get on Pin 1 to pin 4 (CCW up the right side of the connector) with your Ohm meter on a low resistance scale. Get someone to hold that while you go to the single lever control, (don't push the big black button in on the 3000 for throttle only), leave it out, 2000 doesn't have one.

With the ignition key in the OFF position you should have continuity between pins 1 and 4 regardless of the position of the throttle lever. Turn the key to ON and the continuity should disappear with the control in N.....this is like the engine is running and triggers aren't shorted out. Slowly, advance the throttle to full firewall position looking for continuity on the meter. If you get it the problem is in the control as I said.

If you don't get it beat on the box with your fist while moving it and have a 3rd person go up and down the cable bundle from the control to the engine a you move the lever back and forth, shaking it like would happen when out in open water and pounding from waves would shake it. If doing any of the above causes you to have continuity you have a short either in the control or wiring bundle between control and engine. If in the wiring harness chafe points would be places where the bundle chafes against something, like coming out from under the gunwhale and into the engine compartment.

If you get no continuity on all these tests the problem is something else.
 
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