Hello everybody, this is my first post here on Iboats. I've got a problem with an outboard that I bought this summer. The motor is a Mariner 25M, Serial 695 S 023015. The best I've been able to tell is that it's in the 1984/1985 range. Shortly after I bought it, I replaced the impeller, spark plugs, propeller, and gear lube. I took it out for a solid two weeks, and everything ran great. The boat then sat for 2-3 weeks until I took it out on another trip. I started running the gas that I purchased towards the end of the prior trip, and not only was it hard to start, but then I experienced some major power loss. The following is the best description that I can provide for now, and this is the problem that I am still experiencing. The motor is somewhat difficult to get started, but once it's running, it generally idles fine. Reducing throttle to the lowest end of travel results in a decent idle. The problem arises once you advance the throttle just past the "START" position on the throttle. Once you hit a very consistent point, just past START, the motor begins to vibrate pretty badly, sputter, and generally run like crap. Any movement past this point results in virtually zero gain in RPM, and continued sputtering, and vibrating. Immediately after experiencing this problem, I switched over to fresh fuel, only to have the same problem. For the rest of the trip, I was able to "PUT" along just fine, and reliably, as long as I stayed out of this "problem zone" in the throttle. After getting back home, I took apart the carburetor. There was a little bit of sediment in it, but nothing horrific. After that, I slapped it back on. Again, I did not rebuild it, but simply cleaned it. None of the jets appeared to be clogged. I also replaced the spark plugs. I bought some fresh gas, tossed in some Quiksilver Quikleen, and Quikcare, and then proceeded to do a decarbonizing treatment with some Seafoam. I took her out on the water today, and the same problem exists. I'm really not sure what to do at this point. I almost want to say that it's electrical, and that it's only running on one cylinder when I'm in the "problem zone" of the throttle, but I would think that problem would be apparent at idle as well. I am going to order a manual today. I'm really trying to avoid having to take it to the shop. Any help from you guys would be greatly appreciated. Thank you.
