Small Engines (Lawn Mowers, etc.): McCulloch FR21 Chainsaw, 2 stroke engines, loose bolts

Question
I have a McCulloch FR21 chainsaw approximately 10 years old. Used for light duty around the house pruning, delimbing, etc. Saw will "crank" and idle at half choke but when attempted to run at full throttle (choke off) saw sounds like it is bogging down until it dies. I understand the problem may be fuel lines that need to be replaced or exhaust ports that need to be "cleaned". How do I remove the respective parts and clean the exhaust ports? Or can you offer any other suggestions? Thanks

Answer
Matt

yes the carburetor needs cleaned and the fuel lines may be cracked, remove the carburetor and document how you took it apart,or better yet take pictures with a digital camera so you can remember how they came apart.Although it varies from one manufacturer to another, identification numbers for 2-cycle carburetors are most often stamped directly into the body of the carb.Also, it's not uncommon for a single repair kit to include extra parts to cover several models, so you'll need to visually match the various pieces needed for your particular carb.

2-stroke engines generally are very responsive to throttle movement and a lack of responsiveness can most often be narrowed down into three categories:

Improper carburetor adjustment (low side adjusted too lean)

Blocked exhaust
a.) Exhaust screen
b.) Exhaust port

Air leaks:
a.) Carburetor base
* Loose bolts
* Leaking gaskets

b.) Fuel hoses
* Loose connections
* Tears or pinholes

c.) Crankcase
* Mating surfaces
* Crankshaft seals