Ok, here's my tale of woe. I have been reading this forum for several weeks and gotten some good advice. Unfortunately, none of it has solved the problem.<br /><br />Bought a 17 1/2 foot fish/ski with a 1984 150 horse Mercury, SN 6569252, from a friend for what I thought was a great price. The boat had been sitting for about a year outside and uncovered. The motor looked great, tank was about half full, no idea about storage procedures but my friend did tell me he had $700 worth of work done last year and the inside of the motor looked great.<br /><br />I filled the tank (built-in, 18 gallon)with fresh gas and oil and took my wife to the lake. The boat cranked and idled great, and when we got out of the no-wake zone, I opened it up and it scared my wife we were going so fast. I backed it down for her but noticed there was no water coming out of the tell-tale and it started to feel like it was slightly losing power, so we went straight back in and brought it home.<br /><br />Checked it out and the hole was just stopped up. Put a new hose on it and cleaned it out with a paper clip and it worked great. Water was shooting out.Went back to lake and it started out running at about 3500 rpm at WOT, doing about 25 mph tops, but after running the whole tank down to almost empty, it would not run over 2000 rpm at WOT and about 12 mph. Previous owner told me he had gotten it up to 57 mph last year. Book says it should run at 5000 to 5500 rpm at WOT.<br /><br />I'm thinking carbs are gummed, so I went ahead and put new plugs in, took the carbs apart and soaked them in carb cleaner, blew everything out with compressed air and put back together with new gasket kits. Took boat to lake and it started and idled great, but would not go over 2000 rpm @ WOT. I put a can of Mercury tune-up spray through it and then I went and got a new portable six-gallon plastic tank with new hose and fittings, put fresh gas and oil in (no oil injection) and it did the same thing--2000 rpm at WOT. I thought it might be the fuel pump, so I went and got a kit since it was so cheap and rebuilt it. Went back to lake--same thing, just like before.<br /><br />Not knowing what else to do, I took it to a mechanic. He said the stator, trigger and coils were fine but the #6 cylinder was not getting spark and the switchbox needed to be replaced. I got a new switchbox, put it on, went back to lake and it did same thing--2000 rpm at WOT.<br /><br />Came home and did a compression check. All checked out between 95 and 100. Used a spark tester and all six plug leads had spark and jumped a 10mm gap. It cranks and runs great at idle, but when you open it up, it just bogs down, won't plane off and won't get over 2000 rpm. Vent on the gas tank is clear, the small tank is new and the vent is open--it just won't run.<br /><br />Sorry this is so long but I wanted to tell everything I have done. What's next? Do you think I need to completely rebuild the carbs with new guts, or something else? I am at my wits end, and I have consulted the Seloc manual. Can't figure out what else to do, but any suggestion is welcome!
