Honda Autochoke FAQ

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This post will help you understand a bit more about the Autochoke system found on most modern Honda mowers, and on many other mower brands that use Honda engines fitted with Autochoke. There are also details about the Honda Service Bulletin (January 2014) related to Autochoke.

Background:
Engines with carburetors need a mixture of air and fuel to run. When an engine is cold, it needs less air at first, and after warming up, needs more air. A controllable restrictor or choke plate is used to make this work on Honda engines. Other designs use a primer bulb to manually inject more fuel for starting, but either version gets the job done by temporarily changing the mixture of fuel and air.

Until recently, many Honda engines had a manual choke built into the throttle cable and control. When you moved the throttle past the FAST position and into CHOKE, the choke plate was closed. After the engine was warmed up, you'd move the lever out of CHOKE and into FAST. This held the choke plate fully open so maximum air could flow.

However, many first-time users of mowers did not understand or realize the purpose of the choke, how to use it correctly, and this resulted in hard or no-start conditions. Further, the control cable could become bent or broken when folding the handlebars for storage, there was extra cost for the parts, exhaust emissions would be worse if the choke was used improperly, the list goes on and on, so there was a lot of good reasons to automate the choke process during engine start-up.

How Honda's Autochoke Works:
On a cold engine, a spring puts constant pressure on the CHOKE CONTROL ARM (blue) to hold the CHOKE PLATE (pink) closed. After the engine is started, heat from the engine warms up the WAX CYLINDER (yellow) causing the wax to expand, pushing the PISTON (purple) out and forcing the CHOKE CONTROL ARM into the opposite direction; the CHOKE PLATE is then opened, allowing more air to enter the engine.

When the engine is turned off and cools, the wax inside the WAX CYLINDER cools and contracts, and the SPRING pushes back on the CHOKE CONTROL ARM. The CHOKE PLATE is moved back into the closed position as the PISTON is retracted back into the WAX CYLINDER.

Common Symptoms and Issues:
If the mower is hard or impossible to start, it could be because the Autochoke is not working. There may also be many other things that can make for hard starting, so don't be too quick to think it is the Autochoke. Clogged carburetors, stale gasoline, plugged air filters, bad spark plug, etc. can and are frequently the most common reasons for poor starting and/or running issues.

Special Note About Warm-Up:
A frequent complaint is when an engine starts, but is then shut down before being fully warmed up, and then won't restart. This typically can happen when using the mower in cooler weather. If the engine is not run for at least 3 minutes, it is possible for it to not fully warm-up, but still get warm enough to activate the Autochoke. Restart attempts may fail, since the choke plate is open but the engine is still too cold to start/run with too much air flowing. If this happens, let the engine cool off a while, so the choke plate can return to the closed position, then when you restart, be sure to let the engine run for a full 3 minutes before you attempt a shut-down and restart.

How to Inspect / Check the Autochoke:
1. When the engine is completely cold, remove the air cleaner cover and filter element. Look in the opening and confirm the choke plate is completely closed.

2. If the choke plate is open, even partially, the linkage may be sticking; skip to step 4.

3. If the choke is fully closed, start the engine and let it run for at least 3 minutes. Shut off the engine and confirm the choke plate has fully opened. Allow the engine to cool for at least 30 minutes. Re-check and confirm the choke plate has fully closed. Repeat this step; the choke plate must fully open after 3 minutes of operation, and fully close after the engine has cooled for 30 minutes. If all this checks out, the Autochoke is working properly.

4. In January 2013, Honda issued a Service Bulletin about the Autochoke. A limited number of Honda mowers may have a defective Autochoke linkage (usually binding or sticking). A mower with a defective Autochoke that is still under warranty is usually repaired at no charge when done by an authorized Honda dealer. Both the Autochoke linkage and the wax cylinder and may be replaced under warranty. It is important to note not all mowers with Autochoke have a defective part, and hard or difficult starting may be caused by other problems (dirty carburetor, clogged air filter, etc.).

Where To Find The Serial Number:
Look on the back of the mower deck:



Affected Honda Mower Models & Serial Number Range
Mower Model Name Serial Number Range
HRR216K8 MZCG-8400001~MZCG-8669999
HRR216K9 MZCG-8670001~MZCG-9100553
HRX217K3 MAGA-2069723~MAGA-2199999
HRX217K4 MAGA-2200001~MAGA-2325178

What About My Honda Engine on Brand X Mower?
Check the engine serial number on the side of the engine block; it is etched, and may be hard to see, so use a flashlilght; here are the affected GCV160 or GCV190 engines that may have a defective Autochoke.

Honda GCV160 Engines:

GJAPA-1000001~GJAPA-2295257
GJAPA-1546575~GJAPA-2295257
GJAPA-1000001~GJAPA-4630773
Honda GCV190 Engines:
GJAPA-3180269~GJAPA-4630773
GJAPA-1000001~GJAPA-7147598

If you think the Autochoke is not working properly on your Honda engine, and it is on a non-Honda mower, warranty repairs must be done by a Honda Engine Dealer; find one using this link:

Find a Honda Engine Dealer

What To Do Next (if Autochoke is not working properly AND your 100% Honda mower is in the affected range):
Have a Honda Mower Dealer inspect and evaluate; they can confirm if the choke is defective, determine warranty status, and perform repairs. Be sure to have the dealer confirm what will or will not be covered under warranty before authorizing any work. Find a Honda Mower dealer using this link:

Find A Honda Dealer

How to Find Out if Your Honda Mower or Honda Engine is Still Under Warranty:
Three ways to find out:
a. Drop me a PM with the serial number; I can look it up for you.
b. Call your Honda dealer and ask them to find out.
c. Call Honda Customer Relations: 770-497-6400

Why didn't Honda contact me about this Service Bulletin?
For service issues that are NOT safety-related, Honda issues the Service Bulletin to dealers only. This Autochoke issue is not safety-related, and is covered under the factory warranty.
Safety-related issues are Product Recalls, and Honda will always send notification to registered owner by mail. Work required by a Product Recall will be done on any affected product, regardless of warranty status.

Where Can I Get a Copy of My Warranty?
Here's a link: Honda Power Equipment Warranty
 
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Dukester60

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Hi!

I have one of the affected models (GVC160 MZCG 88986). Its two years old so im pretty sure its out of warranty. You would think Honda would at least honor the parts for repair. I do mower repair on the side for 20 plus years and of coarse I do my own but this is a first. My question is which parts are affected and how do I get access to them.

Just joined this forum and it looks like a keeper!!!

Dukester60
 

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Hi!

I have one of the affected models (GVC160 MZCG 88986). Its two years old so im pretty sure its out of warranty. You would think Honda would at least honor the parts for repair. I do mower repair on the side for 20 plus years and of coarse I do my own but this is a first. My question is which parts are affected and how do I get access to them.

Just joined this forum and it looks like a keeper!!!

Dukester60
Welcome, Dukester60!

Any Honda dealer can obtain parts, but probably need to be 100% sure there is an actual problem. Is the choke actually sticking open or closed? Not a hard job to swap out for updated parts. Get me the complete engine serial number and I can find out warranty status for you.
 

Dukester60

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Mornin Robert,

Wow that was a very fast response!! Thank you!

I have removed the carb and actually put heat gun on the wax cylinder. The piston doesnt even come out a little. Im thinking that is the problem as when I restart it needs help. I move the choke control arm to the point that it holds the choke plate slightly open and it takes off normal.

Here are the numbers I have here at work:

MZCG8898686
Model HRR2169VKA

Thanks again for the quick response.....

Gary
 

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MZCG-8898686
Model HRR2169VKA
Gary:

Okay, that mower still has some of its original 3-year warranty remaining. Honda never received any registration details from you (I assume you bought it new) so the warranty start date would be the "Invoice Date" and this mower was invoiced on 7/10/2013, so the factory warranty will expire on 7/10/2016. :thumbsup:

Next, to see if the repair will qualify for warranty, a Honda dealer must inspect and evaluate the issue. If the dealer determines a part is defective, they make the repairs and bill Honda. I'd urge you to get this done ASAP, but spring is a very busy time, and dealers are swamped with service work.

Use this link to find a dealer close to you; be sure to check off the SERVICE box.

Find A Honda Dealer

Finally, if you have any proof-of-purchase that shows the mower was purchased AFTER 7/10/2013, bring it to the dealer so they can update your registration records, and add a bit more time to the warranty.
 

Dukester60

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Actually its a friends mower and hes trying to find the receipt. You have been a HUGE help....I will let you know how things go,

Thanks again...
 

Dukester60

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Hi Robert,

Gary again. I Found the parts and actually got them very quickly. Our local repair outfit says wait time 2-4 weeks so i said ok.......

My question is (the new thermowax looks alot more heavy duty) is there any special install issues procedures I should be aware of? I removed some black atv silicone when removing the original thermowax from the housing. It looks bigger initially but bim hoping its the correct one. The choke plate looks like it is improved also. I have really worked my butt off to get these parts, hoping to get this mower finished and out of my shop.

Thanks for your help....

G
 

asit3

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Hi Robert,

Can you check it up for my Honda mower? Thanks in advance.

Model: HRR2169VKA
Sr. No.: MZCG-8696038
 

asit3

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Hi Robert,

Can you check it up whether my Honda mower is covered? Thanks in advance.

Model: HRR2169VKA
Sr. No.: MZCG-8696038

My Honda lawnmower stopped while cutting lawn and now it does not start.

I cleaned carb, replaced new spark plug however it still does not start. Could it be a choke issue?

My mower info:

Model: HRR2169VKA
Sr. No.: MZCG-8696038

Help greatly appreciated.
 
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