I purchased a Max IV about a week ago and have been working hard to get it back running well. The previous owner let it sit a year and I've done the following- Removed and replaced fuel with ethanol free fuel, put seafoam in the fuel, replaced the fuel filter, replaced both plugs, replaced the fuel pump, cleaned the interior of the carburetor (it had yellowish film on the bottom), adjusted the idle and tightened the chains. The clutch belt looks like it working fine, climbs to the top of the top wheel and moves into a tighter radius when the upper moves to a larger radius.

Here's the issue, on flat ground the power is fine, goes about as fast as I'd like it to but as soon as I hit a slight incline (and I hit a ton of those short very steep hills where I hunt) it bogs down and will sometimes die if I don't apply a little choke, and sometimes it dies anyway. It slows to a crawl, I could walk faster that this can get up those hills. I have the B&S Vanguard 18hp engine in it. Am I expecting too much from this? Should I be able to power up hills or is this normal behavior? Any hints as to what to try next would be greatly appreciated.