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I own a Honda 4120 HA lawn tractor that I bought new in 1999. We have a 2 acre acreage. It has been a very good tractor but lately has started back firing and losing power. I chad to change one of the plug caps, I have changed the fuel pump, fuel filter, carburetor float and needle valve. What else could be causing the problem? Could it be the governor? I think it is running to lean.

Re: Dennis

dhei said:

I own a Honda 4120 HA lawn tractor that I bought new in 1999. We have a 2 acre acreage. It has been a very good tractor but lately has started back firing and losing power. I chad to change one of the plug caps, I have changed the fuel pump, fuel filter, carburetor float and needle valve. What else could be causing the problem? Could it be the governor? I think it is running to lean.

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Sounds like a compression / valves / timing issue, maybe? Backfiring can happen if the timing is out of sync or valves are way out of adjustment.

Do you have a Honda dealer nearby that has some experience with these older tractors? Might be best to have them inspect it. If you prefer to DIY, a paper shop manual from Honda is worth every penny; Honda sells them on eBay and Amazon:

Honda Power Equipment Shop Manuals on eBay
Honda Power Equipment Shop Manuals on Amazon

Here's another forum with some active Honda tractor users; you may wish to ask/post your detailed questions here:

My Tractor Forum - Honda

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We moved your thread to the Small Engine & Mower Repair forum.