First things first, thank you to everyone who has posted their ideas and suggetions to help figure out my power loss problem with my Johnson 115 4 cyl. made in 1973. Here is where I am now. CARBS rebuilt, FUEL PUMP replaced, new plugs, watched the engine run at night in the dark but could not detect a spark or an arc from any of the coils shorting out, tried a different Power Pack, different Fuel, Result = Power Loss continues.
Here is how the thing goes from ramp to ramp, maybe someone else has some ideas?
We start the engine and it idles fine, but as soon as I shift into gear, I can tell it is only running on 1 or 2 cylinders. Problem is that it only does it in the water when pushing the boat, so checking things like plug wires etc, seems very dangerous to do while the motor is running in gear.
Anyway, we travel at 6 MPH out of the dock area and onto the open water that leads to the bay. I slowly give the engine more gas, but even at full throttle, we are barely moving faster than if we were paddling a canoe. We continue at this much reduced level of power for perhaps another 10 minutes, then the engine suddenly comes to life and in seconds we are on plane. The difference in power is much more than double. I don't know if it is possible to run on one cylinder, but it feels like that much of a difference from one to the other. We go full tilt for about ten seconds, but then it dies down again. We putt along for another hundred yards or so and WHAM, off we go again, full speed ahead, flying over the water, but then.... it dies back again,...... 50 yards more the putt putt speed , then all of a sudden she roars to life and off we go like a water rocket again.
This all takes place in about the first twenty to thirty minutes on the water, after that , the rest of the day is perfect and so is the performance of the 115 Johnson. Three hours later we fly back in from the bay without a hickup. At the no wake zone we cut the power back and run at 6MPH for the last 300 yards until we reach the ramps.
If not for the first twenty or thirty minutes, I'd say the boat ran just great, but I am afraid we will be way out there in bigger water someday and whatever is causing this power loss will take ahold of us completely and not let go. If that were to happen, I don't know if we could make it back if the weather turned on us out there. Any ideas ? John
Here is how the thing goes from ramp to ramp, maybe someone else has some ideas?
We start the engine and it idles fine, but as soon as I shift into gear, I can tell it is only running on 1 or 2 cylinders. Problem is that it only does it in the water when pushing the boat, so checking things like plug wires etc, seems very dangerous to do while the motor is running in gear.
Anyway, we travel at 6 MPH out of the dock area and onto the open water that leads to the bay. I slowly give the engine more gas, but even at full throttle, we are barely moving faster than if we were paddling a canoe. We continue at this much reduced level of power for perhaps another 10 minutes, then the engine suddenly comes to life and in seconds we are on plane. The difference in power is much more than double. I don't know if it is possible to run on one cylinder, but it feels like that much of a difference from one to the other. We go full tilt for about ten seconds, but then it dies down again. We putt along for another hundred yards or so and WHAM, off we go again, full speed ahead, flying over the water, but then.... it dies back again,...... 50 yards more the putt putt speed , then all of a sudden she roars to life and off we go like a water rocket again.
This all takes place in about the first twenty to thirty minutes on the water, after that , the rest of the day is perfect and so is the performance of the 115 Johnson. Three hours later we fly back in from the bay without a hickup. At the no wake zone we cut the power back and run at 6MPH for the last 300 yards until we reach the ramps.
If not for the first twenty or thirty minutes, I'd say the boat ran just great, but I am afraid we will be way out there in bigger water someday and whatever is causing this power loss will take ahold of us completely and not let go. If that were to happen, I don't know if we could make it back if the weather turned on us out there. Any ideas ? John
