Motor runs rough at low rpm

[pscartozzi]

I have an 89 Force 125. It runs rough in the midrange. Idle seems OK, top end OK, midrange is really rough. <br />Any thoughts on where to look?<br /><br />Thanks,<br />Perry

 

[sony2001]

Re: Motor runs rough at low rpm

Have you done any repairs recently?<br /> " " " " decarbonizing?<br /> " " checked the timing?<br />Are you using Champs or NKG plugs?

 

[pscartozzi]

Re: Motor runs rough at low rpm

The plugs are Autolite, and they're recent. I need to check the timing. What exactly is decarbonizing, and how do you do it?<br /><br />Perry

 

[sony2001]

Re: Motor runs rough at low rpm

Perry QUICKSILVER POWER TUNER is a good decarbonizer. Follow instructions and don,t breath the stuff or put it directly into the cylinders of a warm engine and let it sit 15 minutes. Then start it up and let it run a little fast. Do 2 cyls. at a time.<br />The best plugs I found for Force 125 are Champs L76V. Or use old plugs during decarbonizing.<br />You could use high octane to cut down on chance of preignition.<br />Timing 32 deg BTDC if using higher octane or<br />30 deg BTDC using regular 87 octane.<br />Just do one thing at a time to see the effect of each change.