03 Merc 125 two cycle rough idle

[dharnie]

Anyone ever disable the 2 cylinder idle so the 125 HP Merc will idle on all 4 cylinders? I read where this model was designed to idle on 2 of the 4 cylinders under 1,000 or so RPMs for fuel economy. I find it very annoying. The engine is an 03. I got it with 50 hours on it and now has about 70. It is in great shape-like new.

 

[MercGuy]

Re: 03 Merc 125 two cycle rough idle

I have a 115 2+2 design, and while there can be some stumbling when 3 & 4 cut in (especially if you hang at that speed), I haven't noticed any problems with the engine at idle.

Can you give some more details about why you think it idle's "rough". Maybe you have another problem.

Cylinders 3 & 4 don't fire at idle because the carbs for those cylinders don't have a low speed jet, only a high speed jet. At the very least the conversion you talk about would require 2 carbs, which would be pricy. I don't know what other problems one would encounter attempting such a project.