Outboard will not throttle all the way

[cmod777debian]

Hello all!

I have a 1983 25hp Mariner Outboard Tiller.

The engine starts fine and runs fine.....to a point.

Throttle will open up halfway and run the boat fine. Once any more throttle is given it will bog the engine down....as if it were being run with the choke on. (I can feel the throttle almost....click over into bog mode) This is a huge problem since I am running it on my bass tracker II and it can only push the boat about 10-12 MPH. I got the speed from a hand held GPS device.

Has anyone else ever heard such a thing before? Is this a carb problem? What would be my best route for repairing it?

Thanks in advance!

 

[Mariner 40]

Re: Outboard will not throttle all the way

iv got the same problem on my mariner 40 iv bought a new prop for a 100 pound and still no different, any help out there chaps

 

[CharlieB]

Re: Outboard will not throttle all the way

Either a weak ignition or a restricted fuel delivery will cause poor WOT performance. You need to teswt both to determine where the fault is.

Disconnect the fuel line, pull the lanyard so the motor does not start, crank and watch for a strong pulsed fuel stream, a weakness in the pump, restriction in any hose or fitting, or air leaking into the system, sucking in between the tank and pump will limit power and can melt a piston from running lean.

Test spark at each cyl using a 7/16 inch gap tester. You need a hot blue arc.

 

[cmod777debian]

Re: Outboard will not throttle all the way

I am sorry....what or where is the lanyard?

So this issue is not because of any carb screws or any settings with it?

thanks

 

[CharlieB]

Re: Outboard will not throttle all the way

My bad, tiller motor.

Lanyard is a cord that attaches to a kill switch and supposed to be attached to the operator, if operator falls out of the boat the kill switch stops the boat from running in circles and killing the operator.

 

[somedatnew]

Re: Outboard will not throttle all the way

It happens the throtal cable probily is slideing in its mounts or is cought on something. I hope this is your problem. I have delt with the same problem on 2 friends boats. If you think the cable is run fine check again.

My bad, tiller motor.

Lanyard is a cord that attaches to a kill switch and supposed to be attached to the operator, if operator falls out of the boat the kill switch stops the boat from running in circles and killing the operator.