lost of power in the water

[rob34]

i have a johnson 70 and the motor runs great when hooked up to ear muffs in my driveway., but when i put it the lake it stalls on me, no power its like it just is bogging out. does anyone have any suggestions on what is going on? i have had the carbs rebuilt,new ball and fuel lines,he took my t'stat out because he said i didn't need it only in cold weather. it smokes real bad also. does this sound like a de-carb problem.this is my first boat so i'm still learning.

 

[ob]

Re: lost of power in the water

Perform a compression test on the engine and post results.We can go from there.

 

[Backlash]

Re: lost of power in the water

As OB said, run a compression check and while you're at it, check the spark. It sounds like you've got a cylinder not making power. It'll seem to run fine under no load conditions but as soon as you put it under load (in the water) the problem shows itself. Run the engine in the water with the cover off and pull one plug wire at a time to check for a bad cylinder (if there's no difference in the sound of the motor when you pull the wire, you've found it). Once you determine which cylinder(s) are not making power you can troubleshoot the problem.<br />Good luck,<br />Backlash

 

[Cricket Too]

Re: lost of power in the water

What kind of idle rpm do you have when your on the muffs? Also I would get those stats back in there, OMC didn't put them there for no reason. Even when the water is "warm" your engine is still cold, in engine terms. It needs to have closed thermostats in it to get to operating temp. quickly, then when they open they keep the pressure of water through the motor correct. Deffinetely start with that compression test to see where your engine is mechanically.

 

[kevkc123]

Re: lost of power in the water

I had some problem with my 1958 johnson 10hp. It turned out to be bad coil. Your ignition is probably not the same, but definately check spark and work back into ignition system.