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Folks:

My 15-year-old mulching Honda mower started to have carburetor float issue as it would fill up the air filter with fuel when sitting for a week. Rather than replace smaller parts inside of or rebuild it, I just bought a new OEM carburetor for 20 bucks.

Installed tonight but when I start it, it surges at idle I can't believe this has a plugged jet as it really is brand new, in Honda packaging, etc.

Is there an adjustment screw somewhere that would adjust idle surging?

Need more information
engine Model number? Type of equipment?

Sorry. It is a Honda Harmony HRR2167VXA. 160cm3 engine. I didn't find the actual engine number but did see the 160cm3 on the block.

Unless you looked up the carburetor with a model and serial number, it's possible you got the wrong one. There are a number of different carburetors used on the GCV160. While many of them will fit, they aren't all interchangeable when it comes to jet sizing.

My motor is the GCV160A0 MU4 R280. I just looked it up and the replacement carburetor noted on ereplacementparts.com is 16100-Z0L-023. That happens to be the one I received from my vendor. Perhaps I need to replace the fuel filter. I looked it up and it's a small, inline part (it appears). I would argue I was able to get strong flow from the fuel line when I checked it.

Do the adjustment screws on the carburetor effect idle surging in any way? I've not adjusted them as I've not yet tried to understand what they do.

If you turn on the choke part of the way, does the surging disappear?

Also, do make sure your anti-surge spring is properly connected. It's the long, skinny spring that connects to the carburetor right next to the throttle linkage.

Ok. So I went and tested it this morning. Cold start, by the way. See my video clip linked at the bottom. A couple of key points to note when watching.

- Full choke on start
- Took 3 pulls cause I had the fuel line off
- Doesn't surge when on full choke.
- at 22 seconds I back it off of choke and go to full throttle. It surges.
- at 28 seconds I put it to full choke and it stops surging.
- at 39 seconds I put it to full throttle and it starts to surge again. I pull it back a bit and it does more of the same.

Also, I think my idle is a bit high; I need to adjust that. Also, the anti-surge spring is in the SAME hold as the throttle. See photo. I know there are two throttle holes. I figured they are for different positions not one for throttle and one for spring. Please clarify if I got that wrong.

I read your message again and tried running it with 1/2 choke and it does NOT surge with 1/2 as well.

https://youtu.be/VfwY52AHRxE

https://www.hondapartsnation.com/oemparts/a/hpe/505ce4cbf870022d24bdc9bc/carburetor

is this your carburetor?

TKH12 said:

Ok. So I went and tested it this morning. Cold start, by the way. See my video clip linked at the bottom. A couple of key points to note when watching.

- Full choke on start
- Took 3 pulls cause I had the fuel line off
- Doesn't surge when on full choke.
- at 22 seconds I back it off of choke and go to full throttle. It surges.
- at 28 seconds I put it to full choke and it stops surging.
- at 39 seconds I put it to full throttle and it starts to surge again. I pull it back a bit and it does more of the same.

Also, I think my idle is a bit high; I need to adjust that. Also, the anti-surge spring is in the SAME hold as the throttle. See photo. I know there are two throttle holes. I figured they are for different positions not one for throttle and one for spring. Please clarify if I got that wrong.

I read your message again and tried running it with 1/2 choke and it does NOT surge with 1/2 as well.

https://youtu.be/VfwY52AHRxE

Click to expand...

The anti-surge spring does not belong in the same hole as the throttle linkage. There is only one correct hole for the throttle linkage, the other one is for the spring.

I went out to the garage, grabbed a few Hondas and got pictures of the linkage, both at the carburetor and at the governor arm. Click the photos to enlarge.

Make sure that the long, straight portions of the anti-surge spring are not wrapped around the linkage. The linkage is supposed to go through the middle of the coil part of the spring, but the straight portions of the spring should go parallel to the linkage without being wrapped around it.

If you connect the linkage correctly and it still surges, next thing I'd check would be the intake gaskets. All the gaskets between the carburetor and the cylinder head must be in good condition and sealing properly, or the engine will surge. If the engine has a metal heat shield behind the carburetor, there will be three gaskets (one from carburetor to heat shield, one from heat shield to insulator block, one from insulator block to cylinder head.) If the engine does not have a metal heat shield behind the carburetor, there will be two gaskets (one from carburetor to insulator block, one from insulator block to cylinder head.)

Here's a diagram showing the location of the gaskets.

Primerbulb120: I think you may have hit the cause. When I replaced the Carb, it came with the large square gasket that is closest to the engine intake; however, it did NOT come with the gaskets (2) between the plastic block and the other one for the filter housing. Both of those were still a bit soft but were misshaped after pulling them off. One may be leaking just a slight bit. I've ordered new ones and will basically have replaced all 3 gaskets at this point. I'll let everyone know if that fixes it.

Thanks for the help everyone!