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| 2001 Johnson 25 HP, < 3 hours, cough'... |
| Author |
Message |
    
Jon
| | Posted on Monday, April 22, 2002 - 10:38 am: | 
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Hi,
I have a 25 HP Johnson, 2001; I have run it twice, totaling about 3 hours. The break in procedure is running a double mix, varying RPM's and keeping it at less than 1/2 throttle for the first 5 hours; the next 5 hours is the same, but full throttle can be used for small periods of time. It was prepped by a dealer and started for the first time, it then sat for 3 weeks with fuel stablizer.
The first time I started it, it was a little difficult to keep it running, it would idle for a few beats and then cough and stall; after warming up it ran well. It then sat for another couple weeks until yesterday. It started right up, but was difficult to keep running until it was warm; the same thing occured with the coughing. When it warmed up I ran it for a couple hours and it ran fairly well, but I was getting an occasional cough out of it at a medium RPM, with a slightly more frequent cough a little above idle. It will idle perfectly when warm, no cough there. I'm wondering if this sounds like a lean low speed jet adjustment, double mix and a new engine, or if it sounds like something else may be happening.
Thanks for any/all advice,
Jon |
Joereeves (Joereeves)
| | Posted on Monday, April 22, 2002 - 06:18 pm: |
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Jon.... That coughing, or spittin back as most of us refer to it (sounds like a mild backfire) is usually caused by a lean setting of the "Slow Speed" needle valve (jet). I retired before that engine was even on the drawing board but if OMC stuck to its usual design, there will be an adjustable needle valve located at the top front section of the carburetor. If it's there, do the following:
Gently seat that slow speed needle valve, then back it out one and one half (1-1/2) turn. Start the engine and set the throttle to where the engine will just stay running (it's going to run lousy). In segments of 1/8 turn, start turning that s/s needle valve in. Wait for the engine to respond after each 1/8 turn. As the rpms increase (and they will), adjust the throttle again to where the engine just stays running. You will reach a point where the engine will either start to die out of it will "cough/spit back". At that point, back the needle valve out 1/4 turn. At some area in that 1/4 turn, you'll find the smoothest setting. Good Luck.
Joe |
Jon
| | Posted on Tuesday, April 23, 2002 - 10:14 am: |
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Joe,
Thank you for the reply, that's exactly what the dealer recommended I do; I got anxious and gave it a shot yesterday. I opened up the jet about 1/4 turn; it seems to have cured the coughing, although I will test it out again today when the engine is cold. As for what they have changed,I don't think they changed much; it's amazing when I compare the early 70's model with the 2001, they are extremely similar.
Jon |
Casimir Mazik
| | Posted on Sunday, May 19, 2002 - 01:39 pm: |
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Hi:
I have a 2002 25 HP Johnson and am having the same problem. I have 6 hours of the 10 hour break-in done. The sputters occur just above idle. I checked the carburetor and there appears to be an idle adjustment but the screw is filled with orange paint. If I fool with this, will the dealer say I voided my warranty? I also noticed there is wet fuel under the carb but not much, possibly coming out of air intake. |
Joereeves (Joereeves)
| | Posted on Sunday, May 19, 2002 - 08:47 pm: |
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Casimir..... There's a good chance that if you disturb that screw that clogged with paint that the dealer will give you a hard time. It sounds like the engine is running lean, but if it were me I would take it back to the dealer, complain tactfully about the problem and let them adjust it under warranty.
Joe |
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