Merc 60 hp With RPM/Fast Idle Problems

[BoatHick]

I have recently ran into a problem, and I don't know where to look. I own a 15 foot Astro with a Mercury 60 hp. The engine is a 2-stroke, and a 3 cylinder. Usually my rpm's, or fast idle, runs in the 2500 range. Well, lately the rpm's and fast idle is running in the 4500-5200 range. The motor redlines at 6000. Now, I have't been running the motor but twice, since I noticed the problem. The last time it happened, was June 10th. I don't want to take it, due to the problem. And, I won't take the boat out on the lake, until the problem is fixed. I am wanting to get my rpm's and fast idle back down, to where it belongs. A friend told me that I could turn the idle down a bit. But, how did the rpm's go skyhigh in the first place? Does a motor's timing jump, like a car's timing? Maybe I should check the spark plugs? I have been looking for some answers on the web, and haven't found a single thing. So, any help will be greatly appreciated. Thank you for your time, and take care. . .<br /><br />------------------<br />Darrell<br />"Ride The Wake"

 

[johnson-4]

Re: Merc 60 hp With RPM/Fast Idle Problems

#1 If you have a throttle cable your problem may lie there. One way to determine is to wath your carb on the motor when you throttle up, if when you throttle down it does not return the carb to its normal idle position I would suspect that is where to start. #2 The next step is to disconnect the throttle cable at the carb and try to work the throttle at the carb if you find the carb is stiff then you may have fuel that has became old and setup in the carb. A little carb cleaner will be the answer here. #3 If the carb works easily but when you place it in the fast idle position and release it, and it does not return perhaps you are misssing a return spring. This is common.

 

[JB]

Re: Merc 60 hp With RPM/Fast Idle Problems

Hey, Darrel. I'm no Mercspert, but it sure sounds like throttle control/cable problems to me. I don't understand the term, "fast idle". To me, 4500-5200rpm is fast cruise. One of our Mercsperts will be along any minute now and explain it to both of us.<br /><br />Good luck.<br />JB

 

[johnson-4]

Re: Merc 60 hp With RPM/Fast Idle Problems

P.S. Check inside the carb for any foreign matter, do this by removing air filter and looking inside carb, without disassembly of carb. Do the throttle check I recommend without running the motor