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Echo PB-413H Zama C1M-K77 Carburetor Tear down Cleaning Rebuild

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Although Echo PB-413H/T models went through many reiterations over the years, Zama C1M-K77 carburetor remained the same.

Because a leaf blower operates in a very dusty environment, it may be necessary to clean and rebuild a Zama carburetor to resolve a problem.

This article will show you how to disassemble, clean and rebuild a Zama C1M-K77 carburetor.

Please make sure to do basic maintenance tasks first (see above for the link to the article)

 

REQUIRED PARTS

I always found it to be more convenient to have spare parts on hand before starting any repair projects. You may want to buy some extra parts in advance (just return them if you end up not using them) to ensure that your repair job is done in a timely fashion.

 

ZAMA C1M-K77 PARTS DIAGRAM

Although I am listing out the parts, it is not economical to buy few individual internal components.

Item Part # Description
00 A021000890 Zama C1M-K77 carburetor assembly
01 P005000980 Screw, purge/primer bulb base
02 P005000620 Purge/primer bulb base retainer
03 12538108660 Bulb, purge/primer
04 P005000610 Base, purge/primer bulb
05 —————— Carburetor body (not avail. individually)
06 12532909860 Cap, low-speed limiter
07 P005000460 Needle, low-speed limiter
08 12532908560 Cap, high-speed limiter
09 P005001650 Needle, high-speed limiter
10 12536312820 Retainer
11 P005001640 Shaft, throttle
12 12531308360 Spring, throttle return
13 12531413930 Screw, throttle return
14 12531613930 Valve, throttle
16 12532713930 Clip, throttle shaft
16 12535008360 LEVER, THROTTLE
17 12534813930 SCREW, THROTTLE LEVER
18 12532408360 COVER, FUEL PUMP
19 12534408560 SCREW, IDLE ADJUST
20 12533308560 SPRING, IDLE ADJUST
21 12531013930 SCREW, FUEL PUMP COVER
22 12533913930 SCREW, METERING LEVER PIN
23 12530008360 REPAIR KIT INCLUDES ITEMS 24-33
24 —————— DIAPHRAGM, METERING
25 —————— GASKET, METERING DIAPHRAGM
26 —————— PIN, METERING LEVER
27 —————— LEVER, METERING
28 —————— VALVE INLET, NEEDLE
29 —————— SPRING, METERING LEVER
30 —————— WELCH PLUG
31 —————— STRAINER
32 —————— DIAPHRAGM, FUEL PUMP
33 —————— GASKET, FUEL PUMP
34 12530308360 DIAPHRAGM/GASKET KIT INCLUDES ITEMS 35-38
35 —————— DIAPHRAGM, METERING
36 —————— GASKET, METERING DIAPHRAGM
37 —————— DIAPHRAGM, FUEL PUMP
38 —————— GASKET, FUEL PUMP

TEARDOWN / CLEANING INSTRUCTIONS

  • Disconnect the spark plug cable
  • Detach 2 ignition wires from the hold down clip; clip is part of the engine cover
  • Remove 5 screws holding down the engine cover. Remove engine cover;
  • Remove the air filter housing cover & air filter and set them aside in a clean environment (i.e. inside zip lock bag);
  • Using a metric Allen wrench, unscrew 2 long screws holding down the retention metal plate inside the air filter housing base;
  • Gently pry off the air filter housing from the rest of the leaf blower;
  • 2 long screws are used to hold down the: (a) air filter housing (b) carburetor and (c) intake insulator;
  • Plug the hole on the insulator intake to prevent dirt penetration;
  • In my case, the carburetor came off with the air filter base;
  • With the carburetor free, gently slide off 2 fuel lines (have some paper towel or drop cloth underneath to catch fuel/oil mixture;
  • As you can see my carburetor was full of oily grime on the outside;
  • Using a Phillips screwdriver, remove 4 screws holding down the purge / primer bulb assembly;
  • Aim 2 fuel line nozzles down to some paper towel and gently press the primer bulb to expel any remaining fuel;
  • While pointing the bulb downward, remove the metering diaphragm and metering diaphragm gasket;
  • Because the metering diaphragm is black, it is very difficult to determine the level of varnish build up; I highly recommend that you replace both metering diaphragm and gasket (found in this kit);
  • At this point, I saw some debris just underneath the metering lever and remove them using cotton swabs;
  • Remove and clean the needle; if the needle is not working or the neoprene tip is swollen your needle adjustment will be out of operational range;
  • Sometimes carburetor cleaner will make it swell up to where it won’t open enough to get fuel through it;
  • Adjust and confirm the height of the tab to flush with the body of carburetor;
  • Verify primer bulb integrity; it should be pulling fuel through the filter to carburetor, then carburetor back to tank;
    • Item Zama Part # Description
    02 0018004 Valve, inlet needle
    03 0019002 Spring, metering lever
    04 0021001 Pin
    05 0020012 Lever, metering
    06 14803005 Screw (meter levering pin)
    07 0016007 Gasket, metering chamber
    08 A015080 Diaphragm assembly, metering
    28 0005004 Welch Plug
  • I placed the now-partially disassembled carburetor on clean paper towel to remove the fuel pump cover;
  • Fuel pump diaphragm and gasket came off with the cover. . Hold it up to a light source. If you cannot see thru it, replace it. Although they might look okay, I recommend that these parts be replaced as part of the rebuild process;
  • Using plenty of cotton swabs and paper towel, clean off all exterior gunk;
  • Re-assemble the carburetor

WRAP UP

With some cleaning and replacing internal metering diaphragms and gaskets, I expect this rebuilt carburetor to last a long time.

I hope this article was helpful to you as you look to rebuild your Zama C1M-K77 carburetor found in Echo PB-413H leaf blowers. When you get a chance, can you do me a favor and sign up for my newsletter so that I can send you updates on my DIY projects?

If you have any questions, please leave a comment below.

Thanks and good luck with your DIY project!

 

REFERENCES