HONDA Engine GCV160 Hunting -

i have read many posts and opinions on this issue of the Honda GCV160 lawn mower engine and the problem of hunting. the original addressee private message box is full so.......

Robert,
I have a question you may be able to help with....
I have a Lawn Boy mower with a Honda engine:
GCV160 {GCV160-S3A-NH1 GJARA 296-1238} with probably less than 48 hours of use at most.
The engine is set up to use an automatic chock release and a constant throttle speed; off/on.

I wanted to check things out prior to using the mower earlier this year. The engine was running fine at the time but I took a look at the spark plug, determined the engine had no spark arrestor, cleaned the air filter element, and took the carburetor off the see what it looked like. However, I was not mindful of the number of gaskets used to re-install each gasket. After finally getting the gaskets and insulator right, the engine ran fine and I ordered some new carb gaskets to have on hand. NOTE: it appears that the carb to insulator gasket was no longer available, and a generic gasket was now being used. I finally found some of the 'original gaskets' and added them to my parts order. (see image of 'original' gaskets) https://www.flickr.com/photos/36268973@N08/

When the new gaskets arrived, I again removed the carb to "add" two carburetor gaskets; one on each side of the air deflector. I saw an exploded view of the system in a Honda engine guide and it indicated the use of the two carb gaskets on both sides of the air deflector, even though the two gaskets where not installed on my engine in the beginning. I put it back together with the two additional gaskets, confident that it would run ok. Unfortunately it did not. The engine now "hunts".

I took it apart again; removed one of the two additional carb gaskets i had added plus the air deflector. It still "hunts". I will put every thing back to the way it was originally, as described above, once I get a new air deflector.

My question is this. The carb itself has a very small orifice on the face of the carb facing the engine, and located directly inline with the mounting bolt. Inside the orifice I can see something brass but I do not know what it is. My question is, did I somehow introduce a small piece of dirt into the R&R process and it has entered that orifice.

Any thoughts.
thank you

"houston.." on the LawnMowerForum.com

Here is an illustration that might help; note that some engines used a metal air guide with gaskets on both sides, while other models just used and air guide-shaped gasket.

Also note the small hole(s) in the various gaskets and parts; they must be oriented in the correct position.

Finally, be sure to securely tighten the two long flange bolts that hold the entire assembly together; even a tiny gap can create a vacuum leak.



You may have some gunk inside the carb causing problems. A new carb has a list price of only $13.34 for this engine, and that's from any Honda dealer:

Find A Honda Dealer

thank you Robert.

i posted the original question. i am responding as another forum registrant because of a problem....

I read you post. I did not know the "air guide" came in two flavors; metal and gasket material.
Since my air guide is made of gasket material, I *now understand I do not need to add the (2) additional carb gaskets...
I am aware that the holes in the gasket *must line up properly with the engine parts. In my attempt to add (2) unnecessary gaskets, they did.
However, even though I lined up the holes in the two carb gaskets (that i did not need), I placed the gaskets up-side-down.
I don't know if that made a difference or not.

So, I *will try again with only the (1) paper air guide\gasket between the carburetor and the insulator block.
Do you know what torque specs are given for the (2) flange bolts...?

Also, one more question about the carburetor gaskets sold on line.
I have seen two alternatives. (I will post pictures of both with this post.)
I will call the gasket that is shown in the Honda carb parts image the "original" gasket and the replacement as "replacement" gasket.
I got the info from eReplacement parts dot com and Shanks Honda Parts online.
One seller said the original gasket was superceeded and only offered the replacement
The second seller had no problem providing the "original" style gaskets; although I now know all I need is the paper air guide gasket.
The air guide gasket mimics the configuration of the "original" carburetor gasket and fits the configuration and insulator block back face perfectly.

PHOTOS: https://www.flickr.com/photos/36268973@N08/

again, thanks for the help.
say hello to area around Atlanta for me. one of the nicest cities I have found. I LOVEd the weather too; even the summers!!

houston.. aka lostman
forum member from houston, texas

lostman said:

I did not know the "air guide" came in two flavors; metal and gasket material.

Click to expand...

I have seen some of the metal guides come with a thin layer of gasket material already applied to each side, as well as plain metal. Suppliers and specs will vary a bit.

lostman said:

Do you know what torque specs are given for the (2) flange bolts...?

Click to expand...

They are 6mm (diameter) flange bolts, and per the shop manual, use a standard torque of 9.8 Nm / 7.2 ft-lb. That said, I personally don't use a torque wrench but go by feel on these, trying to find a good spot around "secure" but before "stripped" :tongue: Here's the Kowa t-handle precision torque tool I use:

lostman said:

Also, one more question about the carburetor gaskets sold on line.
I have seen two alternatives. (I will post pictures of both with this post.)
I will call the gasket that is shown in the Honda carb parts image the "original" gasket and the replacement as "replacement" gasket.
I got the info from eReplacement parts dot com and Shanks Honda Parts online.
One seller said the original gasket was superceeded and only offered the replacement
The second seller had no problem providing the "original" style gaskets; although I now know all I need is the paper air guide gasket.
The air guide gasket mimics the configuration of the "original" carburetor gasket and fits the configuration and insulator block back face perfectly.

Click to expand...

Either style should work okay (original or superceed). Honda probably changed suppliers, or had some engineering reason (emissions/heat/???) to change the design.

Reply to Robert Re: HONDA Engine GCV160 Hunting -

I am still working on my GCV160 Honda Engine. Thank you for the update.
I noticed that, had i looked a bit closer, you provided the torque settings in your second post.

I did put everything back together properly this time; one gasket at a time per your diagram. however, the engine was still "hunting" so it looks like I will replace the carburetor since it must have picked up a piece of crud somewhere.

I did discovered yet another question if you don't mind ?

Your latest exploded carb/gasket view shows something called (1) "air filter packing", and next in line of assembly is the (2) "carburetor packing".
In addition, I have a thin "metal piece" which is exactly gasket shaped but I do not know what to do with it.
(I thought it belonged somewhere between the air filter housing and the choke side of the carburetor.)

Any suggestions on this (3) items while i wait on a carburetor to arrive.

thank you
lostman
houston, texas

Re: HONDA Engine GCV160 Hunting - hopefully LastPost

Reply to Robert
Re: HONDA Engine GCV160 Hunting:

hopefully this is my last question......:biggrin:

my new carburetor came today and i am about to install it..

in order to avoid the chance of any vacuum leaks, i still have questions about the gaskets and parts shown in your exploded view posted earlier to this thread.
The exploded carb/gasket view shows three gasket-like things called "packing". See: (1) insulator packing (2) air filter packing, and (3) carburetor packing.
In addition, I have a thin "metal piece" which is gasket-shaped and fits somewhere between the air filter housing and the choke side of the carburetor; but where??

Any information you can provide on this items will be appreciated.

thanks again
lostman
houston, texas

Re: HONDA Engine GCV160 Hunting - hopefully LastPost

lostman said:

In addition, I have a thin "metal piece" which is gasket-shaped and fits somewhere between the air filter housing and the choke side of the carburetor; but where??

Click to expand...

That thin metal part is the air guide; it goes between the insulator and the carburetor.

The air guide may have gaskets already attached, or it may just be bare metal and require the gaskets to be fitted on both sides.

FYI, the air guide blocks hot air from the engine cylinder away from the carburetor, and helps prevent vapor lock.

Re: HONDA Engine GCV160 Hunting - hopefully LastPost

robert@honda said:

That thin metal part is the air guide; it goes between the insulator and the carburetor.

The air guide may have gaskets already attached, or it may just be bare metal and require the gaskets to be fitted on both sides.
FYI, the air guide blocks hot air from the engine cylinder away from the carburetor, and helps prevent vapor lock.

Click to expand...

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the engine i have uses an air guide made of gasket material only.

the thin metal part i was referring to is shaped like the air filter gasket (see the link below for the gasket shape only), but it is bright metal, and about 1/32" thick.
Gasket- Air Cleaner [17228-ZM0-000] for Lawn Equipment | eReplacement Parts

could it be the air filter "packing" gasket i asked about earlier?
your exploded view above shows (3) three gaskets referred to as "packing" gaskets; air filter, carburetor, and insulator. However, i do not understand the word "packing" in association with a gasket.


thanks again....
lostman

Re: HONDA Engine GCV160 Hunting - hopefully LastPost

lostman said:

the thin metal part i was referring to is shaped like the air filter gasket (see the link below for the gasket shape only), but it is bright metal, and about 1/32" thick.

Click to expand...

Now I'm confused; never seen this part in metal, only gasket-type material only. I will ask an engineer.

Is it possible the metal part is not Honda OEM?

Got a photo ?

Re: HONDA Engine GCV160 Hunting - hopefully LastPost

Opps. not good to confuse the expert.
The part was already installed on the Troy-Bilt mower with Honda G160 engine when I purchased it, so I tend to accept it was Honda OEM.
I also do not have a picture of it, and I am not *positive how I installed this mystery part; which suggests to me that one side was a bright metal, and the other side may have been gasket material. If so, perhaps that is what makes it a "packing gasket". I would have pointed the metal side toward the air filter housing.
I am reluctant to remove the carb to get a photo of this part since my engine is running very well, thanks to you. I did purchase a new $13 carburetor, installed it per the exploded schematic you provided, and it cranked and ran with no sign of any 'hunting' symptoms. I have used the mower three times since the new carb was installed, and the mower is running better now than when I bought it.

thank you for your willingness and ability to help all of us coming to this forum seeking assistance with our Honda engines...!

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robert@honda said:

Now I'm confused; never seen this part in metal, only gasket-type material only. I will ask an engineer.

Is it possible the metal part is not Honda OEM?

Got a photo ?

Click to expand...