Gcv160 running lean

[38racing]

Working on friend's mower with gcv160. Carb looked resl clean but I put it through ucs anyway. Still surging and smooths out by applying choke. I'm going to persue more carb cleaning but just wonder if valves out of spec could csuse same symptom although I don't recall coming across that in the past.

[bgsengine]

Well, it's an OHV, so checking and adjusting valves should be a no-brainer anyhow? And yes, Valve issues can cause a lean surge (unmetered air, exhaust backpressure, etc.) I'd have checked and adjusted valves by now and/or swapped carb to a known good or new carb. (and carefully inspect each and every carb mounting gasket to be sure they're completely sealing all the way around - Gaskets for Honda can be crazy and what seems like it fits perfect, suddenly isn't because it doesn't seal the *other* mating surface, and you get air leaks.. or they get installed upside down or backwards or in wrong order, or slip out of place just a hair, and so on..) before resorting back to further cleaning attempts. There's LOTS to inspect on a Honda and they can catch even the best of us with their pants down...

[38racing]

Thanks. I went the cleaning route before checking back here. Since I've seen where guys have opened the jet a bit I went aggressive on the cleaning rods. It ran perfect for 5 minutes, then went rough again. Applying choke now makes no difference until it reaches point of puffing black. I have a jet from another carb so I'll see how it runs on it. If no good I'll check the valves. Gaskets looked ok. Spraying carb cleaner at the carb to block area made no difference before.

[KE4AVB]

Sometimes it is better to just replace the carb since the OEM carbs are only around $20. But be aware there is multiple carb for the GCV160 and you must order the correct one based on the spec and serial numbers.

[38racing]

Sometimes it is better to just replace the carb since the OEM carbs are only around $20. But be aware there is multiple carb for the GCV160 and you must order the correct one based on the spec and serial numbers.

And as usual it seems cheaper even with shipping and $ exchange to buy it from a USA vendor.

[KE4AVB]

Sorry 38 I keep forgetting you're North of the border.

[38racing]

Update: I did a bit more carb work. Put on one I had labeled as flooding. It did start missing as I expected as if I closed fuel shutoff it would run perfect. So I used the valve compound on the seat . Seemed to run better both nolad and load but sometimes still would miss a bit. So I did pull the valve cover. Intake good at .006 but exhaust was .014 or greater. I reset to .008. I happen to check YouTube for the vover rtving and glad I did. Now aware that the cover meshes with the timing gear shaft. So ran decent for a test today. I'm going to take it somewhere tomorrow that needs cutting for a full test.