Please help! Johnson 25hp won't keep running while in gear

[cwitmer]

The motor will start up fine but once put into gear it sputters and dies. The water appears to be moving through the motor fine. The plugs were cleaned, carb was cleaned, electric cellanoid was replaced, and yet the problem still exists. The motor sat for about a year without being used but the year prior to that it worked fine. It almost seems like it is running out of gas as it runs fine until you move the throttle to put it into gear, then it will sputter and die but yet start right back up. I'm not sure of the motor year but it is an older one. Any help/advice would be greatly appreciated. I realy hate to have to tow it to someone to look at, especially if it is just something I can do myself. Thanks in advance.

 

[12Footer]

Re: Please help! Johnson 25hp won't keep running while in gear

Welcome to iboats.This engine may be running just fine...On one cylinder. The thing that changes most when a 2cycle is placed under a load, is the momentum.This means, thay sound pretty good in neutral, with the other cylinders carrying the dead one, until it is thrown into gear, and it dies.<br />We need to determine what exactly is going on. A compression test is the first thing to do, followed by a carefull inspection of the plugs when you have them out for the compression test.<br /><br />My best guess is, one cyclinder is not firing, but we gotta find out for sure,and why.

 

[cwitmer]

Re: Please help! Johnson 25hp won't keep running while in gear

Would you be able to tell me what the compression reading should be? I don't know the exact year for the motor, probably in the 80s. Also, if this comes back fine, what should be the next step? I had it out on the water today and the motor would stay running as long as you fiddled with the red knob that is on the fuel cellanoid if that helps at all?? We will try to do the compression test early next week. I really appreciate all of your help.

 

[Yepblaze]

Re: Please help! Johnson 25hp won't keep running while in gear

Sounds to me like it's starving for gas. You say it will stay running if you mess with the enrichener. That would indicate it's running off the enrichener rather than the carb. <br /><br />Perhaps some old gas had dried up in the carb while it was stored. That would require that you remove the carb, dissasemble, and clean all jets and passageways. You can use spray carb cleaner, and compressed air. Once removed you can look towards the light through the jets and observe the passageways are clean.<br /><br />While checking compression it's not so much, how much, but just that both cylinders reach a number within 10-15% of each other.<br /><br />Rather than clean the plugs, replace them. Many times I've seen fouled plugs that would not "clean up" to an acceptable level.

 

[cwitmer]

Re: Please help! Johnson 25hp won't keep running while in gear

We ran the compression test, both came back at 130, both spark plugs are firing ok, any suggestions on what to try next? Thanks for all of your help.

 

[petryshyn]

Re: Please help! Johnson 25hp won't keep running while in gear

Have you followed Yepblaze's advice? I think he's nailed it.........clean the carb.