Surging Predator Engine. Governor?
I have a Predator engine that I put on my Horse Tiller. It surges dramatically at full throttle and it stops surging if I choke it half way or so, but the speed also decreases. I am aware that I could exchange it at Harbor Freight at least for another month. From here and some go kart sites, I have heard that a surging engine can be caused by a too small main jet in the carb. I got another jet so that I could bore it out a little although it turns out my littlest bit is probably larger than I would want. The range seems to be ~.070-.095".
However, I am now thinking that the surge is just totally due to the governor attempting to slow the engine down. The engine actually seems to run great. It doesn't stumble or anything. If I block the governor rod from retarding the throttle, the engine runs steady and smooth. I would guess that it would require shortening the governor rod by almost a quarter inch (it is not adjustable of course) to allow a non fluctuating effect. I could bend it of course, but that doesn't seem appropriate. If I can figure out how to easily slip the carb. off, I could reattach the rod to a 1/8" further away hole where the spring that attaches to the throttle handle is hooked. That spring moves the governor around a little for speed control.
I don't actually know how to check speed on a little engine. I do have an old auto tack, if I knew where to hook it up. I wouldn't want to over rev this engine, but it sounds like other engines I use even when I block the governor. I have heard that the go kart guys just take the governors off. Of course, these are the geniouses who increase valve springs, rejet everything, and replace flywheels so they don't blow up their keesters.
Anyway, does any one have any thoughts. I know a couple of you have several of these engines.