Alright guys, question for you. I have a 2002 F115 that's ran flawlessly for its entire life, I think it's not started twice in 15 years, and otherwise I've had zero problems with it. Except....
For a number of years the RPMs have been low. Anywhere from 4500-5200 WOT. It's actually my father's boat (although I'm the only one who uses it), which is why I can't say for sure how long it's been like this. I only started paying attention to the RPMs about five years ago, although I always remember it running in the low-mid 30's as far as WOT MPH goes, so it's probably been an issue for quite awhile. Having said that, again I'd like to stress that we haven't had any other problems with the motor. Over the last couple years I've played with props, sticking with the cheaper Yamaha OEM aluminum ones mainly because of price, and the knowledge that I might have to try a few. Its had 19, 17, and 15 pitch props on it, which got me anywhere from 4800-5200 max RPMs, at its best performance. I will say that it tends to dog down in rough conditions or with a heavy load, more than I would think it should, although that's just speculation on my end. For example, in 2-4 foot rollers, I'm only seeing low 4000's and a speed of 25-29 mph. If I rev it down and then back up, I can usually get higher RPMs until it hits a decent sized wave. I know it's hard to qualify "rough water", but I do have extensive experience on the water, and I can tell you I'm not running it anywhere near its limit for what it can handle. I've been in water that was too nasty to get any decent speed going, and the boat seems sluggish at conditions below that level. I would say it averages around 4900-5100 RPMs in decent conditions at WOT, trying to trim it up to get it past the very low 5000's just causes the prop to blow out.
The strangest thing to me is that other than the RPM/speed issues, the motor has given us no trouble at all, I'm not seeing any other symptoms. I'll be the first to admit I don't have much mechanical experience, and my dad is the type who waits until there's a problem, then drops it off at the mechanic and pays whatever they tell him to, so feel free to dumb down any answers or advice or tips you guys have! I've heard a bit about potentially clogged injectors or VTS being a possible culprit? For the record, it's hung on a 2002 Lund Fisherman 1700. Thanks for any help you guys can provide!
For a number of years the RPMs have been low. Anywhere from 4500-5200 WOT. It's actually my father's boat (although I'm the only one who uses it), which is why I can't say for sure how long it's been like this. I only started paying attention to the RPMs about five years ago, although I always remember it running in the low-mid 30's as far as WOT MPH goes, so it's probably been an issue for quite awhile. Having said that, again I'd like to stress that we haven't had any other problems with the motor. Over the last couple years I've played with props, sticking with the cheaper Yamaha OEM aluminum ones mainly because of price, and the knowledge that I might have to try a few. Its had 19, 17, and 15 pitch props on it, which got me anywhere from 4800-5200 max RPMs, at its best performance. I will say that it tends to dog down in rough conditions or with a heavy load, more than I would think it should, although that's just speculation on my end. For example, in 2-4 foot rollers, I'm only seeing low 4000's and a speed of 25-29 mph. If I rev it down and then back up, I can usually get higher RPMs until it hits a decent sized wave. I know it's hard to qualify "rough water", but I do have extensive experience on the water, and I can tell you I'm not running it anywhere near its limit for what it can handle. I've been in water that was too nasty to get any decent speed going, and the boat seems sluggish at conditions below that level. I would say it averages around 4900-5100 RPMs in decent conditions at WOT, trying to trim it up to get it past the very low 5000's just causes the prop to blow out.
The strangest thing to me is that other than the RPM/speed issues, the motor has given us no trouble at all, I'm not seeing any other symptoms. I'll be the first to admit I don't have much mechanical experience, and my dad is the type who waits until there's a problem, then drops it off at the mechanic and pays whatever they tell him to, so feel free to dumb down any answers or advice or tips you guys have! I've heard a bit about potentially clogged injectors or VTS being a possible culprit? For the record, it's hung on a 2002 Lund Fisherman 1700. Thanks for any help you guys can provide!
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