125 Merc. losing RPM's

[Jerkalip]

I recently purchased a 2001 125 HP Merc ELPTO that runs pretty well. However, when I put it on a flush, the motor sounds irratic. If I am at 1200, it will run for a while then pop, and the rpms drop to about 600, then goes up to 12 again. If I run it to 2200 rpms, it'll pop and drop to about 1600, then go back up. I put it in the shop and they said it needed a tune up. Had them tune it up, took it on a fishing trip (ran good), then come home to flush it and it still does it. Is this normal, abnormal, is there another problem?

 

[achris]

Re: 125 Merc. losing RPM's

This is not normal and the 'pop' sounds like a 'lean pop'. One of the carbs is running lean. As these engines only run on the top 2 cylinders at low engine speeds, then try opening up the idle screw on the top 2 carbs by 1/8 of a turn.

Chris...........

 

[Jerkalip]

Re: 125 Merc. losing RPM's

Thanks Chris. Does it make a difference if I try this while the motor is running or not? I'm gonna try to get to it today. Thanks again.

 

[Jerkalip]

Re: 125 Merc. losing RPM's

Hey Chris, thanks a bunch! I adjusted the top two carb's and it's running fine now. You probably saved me a $100 and a bunch of aggravation!