I have a 1989, 25 hp mercury outboard. Was working as most 25 year old outboards would for most of the summer...good, a couple shakes and shut offs here and there. I took it out about 6 weeks ago and after running it for 20-30 minutes, the motor bogged down and wouldn't get above 1600 rpms. Worked the throttle a bit, and eventually would get back to full throttle rpm's, but kept bogging down here and there. Got home, flushed it on motor muffs (I occasionally fish brackish water), and the motor seemed to run normal.
Next couple times I took it out (freshwater) the motor ran as it normally does without out of the ordinary issues. Took it out in saltwater last weekend and almost as soon as I got it on the water the motor bogged down and wouldn't get above 1600 rpms. Got home, motor muffs, ran seemingly fine...I even put it in gear and gave it some gas and the rpms jumped to 2500 (I immediately dropped it to neutral after. Putting in gear on muffs may be a no no but I couldn't help myself knowing it would probably achieve higher rpms)
So why can I not achieve higher rpms in the water, particularly when I'm running in saltwater? Most likely issue (from what ive read) is some junk in the carbs, but the motor seems to be able to achieve higher rpms out of the water. And is it only coincidence that this has only happened when running in saltwater? I don't have the money to have someone tear it apart and diagnose every little thing. It is an old motor and I just want to get it back to running how I know it can. And yes...the motor has been flushed thoroughly after every saltwater outing. Any info would be appreciated!
Next couple times I took it out (freshwater) the motor ran as it normally does without out of the ordinary issues. Took it out in saltwater last weekend and almost as soon as I got it on the water the motor bogged down and wouldn't get above 1600 rpms. Got home, motor muffs, ran seemingly fine...I even put it in gear and gave it some gas and the rpms jumped to 2500 (I immediately dropped it to neutral after. Putting in gear on muffs may be a no no but I couldn't help myself knowing it would probably achieve higher rpms)
So why can I not achieve higher rpms in the water, particularly when I'm running in saltwater? Most likely issue (from what ive read) is some junk in the carbs, but the motor seems to be able to achieve higher rpms out of the water. And is it only coincidence that this has only happened when running in saltwater? I don't have the money to have someone tear it apart and diagnose every little thing. It is an old motor and I just want to get it back to running how I know it can. And yes...the motor has been flushed thoroughly after every saltwater outing. Any info would be appreciated!