A little advice please. I am rebuilding/ reconditioning a Bluebird aerator with a Honda GX120. I purchased this from a Home Depot rental that was closing. The stop switch had been broken and rather than fix it, they just parked it. Then I came along, took a chance, and took it off their hands CHEAP. I replaced the switch and it started right up. I didn't really need an aerator. I kind of bought it for fun and to re-sell, but I got such a good deal I couldn't bring myself to sell it.

Ultimately, it sat for a couple years and got carb rot. So, I'm doing a little work on it to get it running for spring and was wondering how far I should go. I was considering rebuilding the engine both because I have no idea of the units history (rentals aren't exactly treated well) and for fun/ to learn. However, I don't really want to spend the cash if it isn't even close to needing a rebuild. A compression test showed 70 PSI, but I have read that compression tests aren't accurate on these motors due to a relief valve. It ran good previously and has no leaks that I can find; although it did seem oily under the gas tank behind the flywheel. The only thing that really concerns me is a lot of carbon build up in the exhaust port, but guess I don't really know what's normal.

Thoughts? Thanks...