I just took delivery of a 2002 boat with 25hp Mercury two cylinder, four stroke, which is sourced by Tohatsu I believe. I tested the engine on a flush muff about a month ago and it started and ran fine, although idled a bit fast. Meanwhile I've been waiting for the guy to get the title straightened out. The boat and motor are as new with maybe a couple hours max on the motor.
I bring the boat home and it cranks a couple revolutions and then stops. I pull the plugs and it looks like it may have hydrolocked in the upper cylinder with fuel. The 100+ degree temps have pressurized the plastic fuel tank with the vent closed so I assume the carb and cylinder have been flooded with fuel. The battery is fully charged. I put the lanyard switch in the off position with the plugs out and crank if for 10-15 seconds. It sounds normal while cranking with the plugs out. I reinstall new plugs and it cranks a revolution or two and then stops, like something is restricting crank rotation. It does the same thing with the lanyard in run or off position.
I don't have a compression gauge yet to fit the small plug thread but that will be my next step.
Any known problems here, or any thing I am missing, or any suggestions?
Vernon
I bring the boat home and it cranks a couple revolutions and then stops. I pull the plugs and it looks like it may have hydrolocked in the upper cylinder with fuel. The 100+ degree temps have pressurized the plastic fuel tank with the vent closed so I assume the carb and cylinder have been flooded with fuel. The battery is fully charged. I put the lanyard switch in the off position with the plugs out and crank if for 10-15 seconds. It sounds normal while cranking with the plugs out. I reinstall new plugs and it cranks a revolution or two and then stops, like something is restricting crank rotation. It does the same thing with the lanyard in run or off position.
I don't have a compression gauge yet to fit the small plug thread but that will be my next step.
Any known problems here, or any thing I am missing, or any suggestions?
Vernon