Loss of RPM's

[the_nstag8r]

I have 100 hours on an 2001 Johnson 225. I was cruising along at 5500 RPM's and immediately had a loss of 500 RPM's. At 2200 RPM's I get a little stumble. I have changed the fuel filter, spark plugs, "idle switch", prop and fuel. I have also cleaned my carbs. I can get my RPM's back by reducing the prop pitch but I can't even pull out of the hole. So, I have gone back to the 15x18. My next step is to replace my fuel tank vent and clean out the line and make sure the throttle cable hasn't slipped. <br /><br />It is pumping water and not running hot. It is burning blue smoke. So, the mixture looks good. I get no warning lights.<br /><br />What else can I try and why do you think this happened?

 

[Cricket Too]

Re: Loss of RPM's

nstag8r.....I have a 99 200 Johnson and recently had the same problem. I'll give you the advice that was given to me on this site. You said you changed the plugs, but did you ever check to see if they are all getting spark. Get a timing light and hook it to every spark plug wire at idle and see if you are getting elec. to every plug. Then try reving it up and see if you lose the spark on any cylider. I did this and found that I had no spark at idle on #6 cyl. and then it would come and go when I revved it up. Replaced the ignition coil and it now works fine. Just something to try, it's better to try and troubleshoot before replacing. Good Luck.

 

[the_nstag8r]

Re: Loss of RPM's

Thanks for the advice. I will try it and see what happens. I did have a problem with #6. That is why I ended up with a new "Idle Switch". I could very well have a problem with the coil/ignition as I increase the RPM's. We'll see what happens. Thank you very much!

 

[Dhadley]

Re: Loss of RPM's

What is an "idle switch"?

 

[the_nstag8r]

Re: Loss of RPM's

Hey, good question! The switch is located on the starboard side of the motor at the bottom of the powerhead. Apparently it cuts out cylinders when you shift. Put it this way. It is replaced. Whether or not that is in fact what it is called or what it does is beyond me. Seeing that my mechanical background is limited, I have to put faith in those people coaching me. It may very well be called something else by someone else and I may have changed the blinker fluid or muffler belt for nothing. lol <br /><br />I am truly in trouble when it comes to mechanicing. I can replace parts but don't ask me to go too far beyond that!

 

[Dhadley]

Re: Loss of RPM's

Ah....thats the shift interrupter switch. It momentarily interupts the spark on the starboard bank as you shift out of gear. It helps releasing forward gear especially if the idle is a tick high.<br /><br />Look up under the flywheel and make sure your 6 outer magnets are still in place (evenly spaced) and not loose.<br /><br />Good luck!

 

[the_nstag8r]

Re: Loss of RPM's

Thank you for the information. I am sorry about the landlubber lingo. I will check the magnets on the flywheel tomorrow.<br /><br />Thank you again!