I'm having an issue with a Force 40 outboard motor (1997 I believe). It runs well at full throttle, but only for about 15 minutes or so. After that, it revs really high, then dies sometimes with one or two little thrusts just before shutting down. After it shuts down, it clicks repeatedly which I am assuming is just the drive shaft winding down, but not sure. After it does this the first time in an outing, it will consistently start and run for about 30 seconds, then rev up and die again, even at half throttle and below. After a few of these cycles, it will not want to start at all until after it has rested for about 5-10 minutes, at which point I have gotten it started again, but then just slowly crept home at about 1/4 throttle not wanting to push it. After a significant amount of rest time (usually overnight), the motor will run fine again for 15 minutes or so, then the same cycle of revving and dying begins again. So far, I have replaced fuel lines from the tank through to the carburetor, replaced the fuel filter, added sea foam to the tank and directly to fuel line and let it sit in the system for 5 minutes per the instructions, but nothing I've tried seems to be helping this particular issue. The motor is also idling a little rough... I typically have to have the throttle lever raised a bit when starting initially, and it does sometimes die at idle, but not too often. The priming bulb feels a bit soft, but if that was the issue, I would think these issues would be happening immediately rather than 15-20 minutes into running, right? Maybe worth trying to replace that anyway? Any thoughts are much appreciated. An example of what the motor is doing can be seen at:
Motor dying - YouTube Video shows from start to half throttle to full throttle, then the revving and dying of the motor.
Motor dying - YouTube Video shows from start to half throttle to full throttle, then the revving and dying of the motor.