2cyl carb rebuild problem


Old 09-29-06, 06:53 PM
PTC123's Avatar
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Join Date: Sep 2006
Location: MA
Posts: 9
Cool 2cyl carb rebuild problem

Hello everyone, I have a problem with a Tanaka 650 chainsaw that was left with fuel in it for an indeterminate but lengthy time. It was also left quite dirty and oily sawdust encrusted. It appears to have good compression but I have no way to test PSI. I have cleaned and/or replaced all fuel system parts from the tank filter through the carb and it still does not run unless I dump fuel in the cylinder or carb throat and it runs only as long at that lasts. The Walbro D-10 HDA carb was pretty shellacked but I used carb clean to blast out all ports and holes I could find and blew them out with compressed air (twice) and replaced both diaphragms and corresponding gaskets. The screen on the main fuel port looks okay and air goes through it fine. Do I need to take it out and clean under it? If so, how do you recommend doing so? I was unable to find an owner/service manual but found a parts catalogs for it instead and followed the exploded views to make sure everything was put back correctly. This is not my first carb rebuild but it is my most perplexing one. Any ideas will be appreciated.
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Old 09-29-06, 10:29 PM
cheese's Avatar
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Have you checked the fuel lines? In-tank fuel filter? You may have to clean the carb in a bath type cleaner to get it cleared out.
Old 09-30-06, 04:21 AM
Join Date: Sep 2006
Posts: 39

try replacing the diaphram........
Old 09-30-06, 04:25 AM
PTC123's Avatar
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Join Date: Sep 2006
Location: MA
Posts: 9
Angry 2 cyl carb problems

Hi Cheese,
I replaced the in tank filter and blew out the lines with carb clean and they appear to be clear. There seems to be fuel on the pump side of the carb but the metering diaphragm stays dry. The needle valve is free moving and the metering lever is slightly higher than the carb body by straight edge. I will try to soak it. Can you recommend a product for the bath?
Old 10-01-06, 02:09 PM
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Join Date: Apr 2004
Location: Upstate New York
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I like Napa's #6402. Good stuff!!! As for under the screen, remove it before soaking and be sure to install the new one that comes in the kit. I'd recommend replacing the fuel lines...a hairline crack (undetectable, most likely) will create a lack of sufficient fuel supply to the carburetor.

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