Idle & WOT RPM suggestions

[JP56]

I have the misfortune of owning an MTD 41AY421S793 chainsaw, which is being marketed as a "Craftsman" 18" 42cc, Model CMXGSAMY421S.

I cannot seem to find the IDLE & WOT specs anyplace online, but guessing by the cc's, I am thinking about possibly 2700 RPM Idle & 13000 RPM WOT, based on similar sized saw specs I have found online.

I would greatly appreciate it if someone could please tell me if I am close on these numbers or possibly give me some exact numbers. I have no idea of who the engine or cylinder head or piston & rings are made by, & want to get it as close as possible to the original settings so I don't blow the junker up.........just yet anyway! :D 

[sawguy21]

Welcome! There is very little adjustment available on new saws thanks to the EPA. Set the idle speed just below where the chain starts to turn when the saw is warm. If you can turn the HI speed mix counterclockwise to the stop, it will require a special tool.

[JP56]

Welcome! There is very little adjustment available on new saws thanks to the EPA. Set the idle speed just below where the chain starts to turn when the saw is warm. If you can turn the HI speed mix counterclockwise to the stop, it will require a special tool.

There are no limiter caps on the saw, and I want actual spec'd RPMs to start with because I do not have years of experience in tuning carbs, so my goal is to start at the basic recommended RPMs, but thanks for the reply.

[Gearbox]

2500 to 2700 is kind of a standard idle . I don't know if I would run that saw much over 12,000 peak. Husky will run their small saws 13500 . You might look it up under who ever manufactured it for craftsman .

[sawguy21]

With no limiter caps turn the high speed to 1 1/8 out then turn back in a little at a time. The saw will increase in speed then falter as it tries to speed up, this is the sweet spot. If you are not confident set it at 12,500 rpm +or- no load.

[Al_Smith]

FWIW you can get on any carb web site and find the exact method which is exactly the same for just about any carb .Suppossidly according to some it's not legal to remove the limiters for a dealer .However as an owner you are not under that edict .Pop them off and tune it .There are no chainsaw police in the USA I know of .There might be some in Canada but they won't say anything about it . :D Pretty good people up there .