Earthquake tiller - Briggs and Stratton engine problems
I recently purchased an Earthquake roto tiller, knowing it needed some carburetor work. When I purchased the tiller it ran, but needed about 7/8ths choke to stay running. I didnít think it would be a big deal to take care of the issue. A good carb cleaning and it would be back in business. Mind you this is a Briggs and Stratton 5 hp engine with the infamous pulsa jet carb mounted to the gas tank.
After I cleaned the carb up, and installed a new diaphram in the pump, I found that the engine ran better, but had a surging issue, except when the tiller was placed under a load. No load, the engine constantly surged. Applying a little choke smoothed things out. I suspected the carb still had debris in it somewhere. As time went on, the engine started running worse, requiring just as much choke to stay running as when I first purchased it.
Another strange problem I noticed was that after cleaning the carb and running the tiller for roughly 5 hours or so, the engine crankcase oil looked like it was becoming diluted with gasoline. I thought it was a fluke and the oil was simply not change from the provius owner, so I changed it.
At this time I also ordered a new carburetor off eBay, and although it was an aftermarket China replacement, I figured it would help take care of the problems. I installed the new carb, and with a fresh oil change, headed out to do some tilling. The engine ran great. I put about 2 hours of use on the tiller, and when I was done, I thought I would check the oil. To my surprise, it was overflowing, and once again diluted with gasoline.
Now Iím stumped. I donít understand how the gas is getting in the oil. This carb has no float or needle, which is the first place I would normally look for a problem. All I can think of now is that the gas tank cap is not venting, but if extra gas was being forced into the engine, I would expect it to run really rich and smoke black, which it doesnít do. Or is the engine just plain shot? This tiller looks like a low hour machine, and the engine has good compression, as far as I can tell.
Has anyone experienced problems like this with the pulsa jet carbs? This is my first experience with them.