1971 Johnson 25HP boggs in gear

I have been reading several posts here for the last month and some have been very helpful. I am stuck now and need some assistance.<br /><br />I have a 1971 Johnson 25Hp outboard. I have had it for the last few years. It was hard to start, but when it started it ran very well, especially at higher speeds. About 6 months ago I was running it and it went from running fine to misfiring and sputtering. To resolve I purchased new fuel, no change. I rebuilt the carb, no change. I changed the fuel pump, no change. I purchased new condensers, points and plugs and set the gap on the points to .020" according to manual. Now the motor is very easy to start and does not misfire or sputter, but it has no top end either. If I am idling, it seems to run ok. As soon as it is in gear...It runs like I have a 5HP motor on the back of the boat. The plugs are oily so I am sure that there is still something wrong with the fuel mixture or the ignition.<br /><br />I am out of ideas on what to check next. <br /><br />Look forward to some ideas from the experts here.

Re: 1971 Johnson 25HP boggs in gear

Have you checked for a hot, blue spark from each plug wire to the block?<br /><br />Sounds to me like you are running on one cylinder.

Re: 1971 Johnson 25HP boggs in gear

Will check to make sure that both are firing.

Re: 1971 Johnson 25HP boggs in gear

Just checked. Getting spark on both plugs when out and grounded against block.

Re: 1971 Johnson 25HP boggs in gear

Crank it up. pull each plug wire (carefully, 15 to 50 thousand volts).<br /><br />If the engine slows or dies that is a good cylinder. If no change that cylinder is not making power.<br /><br />If you have a dead cylinder, check compression, then reeds.<br /><br />Good luck.