camman825
New member
So I bought a 14 foot Fishmaster 140 a couple weeks ago with a 1996 Mercury 25HP 2 stroke on it. The motor came with the boat brand new. Motor starts and idles strong. Starts within a second or two (cold and warm).
I have been having trouble getting it to get past 1/4 throttle and onto plane. It will get onto plane and get past 1/4 throttle if I shift my weight two to three feet to the front of the boat (it has a console in the middle). When it gets on to plane and full throttle, it keeps going until I kill the motor or slow down, then when I (start it up and) give it throttle again, same thing, it only goes 1/4 throttle slow speeds and won't plane unless I shift my weight. What could be my issue? I have rebuilt and fully cleaned the carb/fuel pump (diaphragm), all new fuel lines and line from the fuel tank (with primer bulb) and new fuel filter. I have listed information below of all the details I have.
Any help would be great.
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1996 Mercury 25HP 2 Stroke Carbureted - Electric Start
Motor starts very strong cold and warm.
Motor idles strong cold and warm.
Motor goes full throttle the first launch and start of the day, after shutoff or idle speed, motor won’t go full throttle (or get on plane) unless driver stands at front of boat to even out weight and help boat get on plane.
Full hand throttle only gets motor to about 1/4 throttle. Somewhat of a bog sound when this happens. No shaking or sputtering, just sounds like it’s under a lot of load or is pulling something.
Carburetor has been rebuilt (new gaskets and fuel diaphragm, set in cleaner for 24 hours and blown out jets with air gun.) Carburetor should be in perfect condition, cleaned out amazing.
New fuel lines under the top cowl and a new fuel line with built in primer bulb to fuel tank.
Fuel tank was used with other motor and worked great.
Fuel filter is cleaned and free of blockages or crud. Reeds look to be shiny and clean. No cracks.
Spark plugs are not oily, and have been tested with an inline spark tester at idle speeds out of water (earmuffs on)
Compression on both cylinders are about 110, within 5 psi of each other. Unplugged each spark plug boot (one at a time) and started the motor putting it in gear (under load), each spark plug/cylinder performs the same solo, won’t push boat forward. They sound and feel the same.
I have been having trouble getting it to get past 1/4 throttle and onto plane. It will get onto plane and get past 1/4 throttle if I shift my weight two to three feet to the front of the boat (it has a console in the middle). When it gets on to plane and full throttle, it keeps going until I kill the motor or slow down, then when I (start it up and) give it throttle again, same thing, it only goes 1/4 throttle slow speeds and won't plane unless I shift my weight. What could be my issue? I have rebuilt and fully cleaned the carb/fuel pump (diaphragm), all new fuel lines and line from the fuel tank (with primer bulb) and new fuel filter. I have listed information below of all the details I have.
Any help would be great.
--
1996 Mercury 25HP 2 Stroke Carbureted - Electric Start
Motor starts very strong cold and warm.
Motor idles strong cold and warm.
Motor goes full throttle the first launch and start of the day, after shutoff or idle speed, motor won’t go full throttle (or get on plane) unless driver stands at front of boat to even out weight and help boat get on plane.
Full hand throttle only gets motor to about 1/4 throttle. Somewhat of a bog sound when this happens. No shaking or sputtering, just sounds like it’s under a lot of load or is pulling something.
Carburetor has been rebuilt (new gaskets and fuel diaphragm, set in cleaner for 24 hours and blown out jets with air gun.) Carburetor should be in perfect condition, cleaned out amazing.
New fuel lines under the top cowl and a new fuel line with built in primer bulb to fuel tank.
Fuel tank was used with other motor and worked great.
Fuel filter is cleaned and free of blockages or crud. Reeds look to be shiny and clean. No cracks.
Spark plugs are not oily, and have been tested with an inline spark tester at idle speeds out of water (earmuffs on)
Compression on both cylinders are about 110, within 5 psi of each other. Unplugged each spark plug boot (one at a time) and started the motor putting it in gear (under load), each spark plug/cylinder performs the same solo, won’t push boat forward. They sound and feel the same.