2000 Johnson 25 HP

" I bought this motor new &#40

" I bought this motor new (still in the packing crate) in April 2000. Right from the start it has had a rough idle. Idles smooth for about 5 seconds then a big cough and it either dies or repeats the cycle. Runs smooth at high speeds.

Is this just the low speed adjustment? If so, can you identify where on the carb' it is and whether your intuition says to turn it out or in and how much?

Thanks,

Mark "

"Mark.... The problem you desc

"Mark.... The problem you describe can be caused by one of two things, or a combination of both. First... check the throttle pickup roller. It should just start to move when the cam contacts it with the scribe mark on the cam being perfectly aligned with the center of the roller. If the cam contacts that roller before the scribe mark centers on the roller, the throttle plate opens too soon in relation to the timing, resulting in the coughing, spitting back etc that you describe.

The second cause is as you suspect.... a lean slow speed jet carburetor setting. Unfortunately I retired before that engine came into being and am not familiar with it. However, it's unlikely that OMC would deviate from their standards so I would assume..... if there is a adjustable s/speed needle valve, it would be at the top portion of the carb, at the rear, on the starboard side. To richen the mixture, turn it outwards very slightly (counter clockwise). Turn it in 1/8 turn segments, waiting a few seconds for the engine to respond before turning again.

If there is no adjustable s/speed needle valve, there would be a fixed brass jet at the top front portion of the carb, and if this is the case, assuming the carburetor is clean, the only option would be to install a smaller jet/orfice. I say smaller due to the fact that the jet would be metering air, not fuel, and the smaller jet would result in a richer fuel flow.

Note that regardless of whether there is a adjustable needle valve or not, that fixed jet at the top front exists.... but do not tinker with that fixed jet if the adjustable needle valve exists.

Joe (30+ Years With OMC)"

" Thanks for the feedback, Joe

" Thanks for the feedback, Joe. Although it doesn't look that way, I wasn't completely brain-dead when I posted the message three times. The server on my end sent an error message when I tried to post it the first two times leading me to believe it didn't post.

Oh well, now I know more about outboards and servers.

Mark "

" Mark.... I understand the se

" Mark.... I understand the server error thing. Andrew has been working on it. I've found that the best thing to do when that server error is encountered is to hit the back button, then re-hit the post button again. Usually that will bring up a notice that the message was already posted, and it will suggest that you click on a hyperlink (continue or something) in said notice. After clicking on that hyperlink, the message is usually found to be posted and all is well.

Joe (30+ Years With OMC) "