Small Engines (Lawn Mowers, etc.)/hitachi chainsaw


QUESTION: Mr. Jones I was recently given a hitachi CS40EA Chainsaw. The carburetor needed a kit, but before I start all the fuel lines are rotton to a point where I just don't know where they go. The carb. is a Walbro WT-993. could you please tell me how to route the fuel lines and what diameter fuels lines this model takes. I know you are very busey, any information will be greatly appreciated, at your convieneance, thank you, Fred.

ANSWER: See this URL for the fuel line part number:

You saw is a Tanaka.

I'm not exactly sure which line fits the saw but 3/32" is very common.  As far as the routing, the main fuel inlet needs to be connected to the line with the fuel filter inside the tank.
Does that make sense>


---------- FOLLOW-UP ----------

QUESTION: Mr. Jones I am now sure  the fuel lines are correct. I can get the saw started, and it will idle but as soon as I try to excellerate to high speed it dies out. I removed the carb. again and cleaned it out and used about 60 lbs. of air blast in all the small holes. Reinstalled carb. and still have the same problem. The high adjustment screw does nothing. Do you believe the carb. has to be replaced? Please let me know what else I can check, thanks Fred

Most of the time the problem is the carb but I have had other issues cause a chainsaw not to accelerate.

Is the muffler port and spark arrestor clean to ensure the exhaust is flowing?

What is the engine compression.

Do you have two fuel lines?


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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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