All good points but back to the OP's dilemma: He has a freebee baler that's been sitting for 8 years, an undefined mower, an undefined rake and no pixs of the hay length. The header is 'bobbing' and missing much of the hay in front of it.
From my experience, this can be caused by ground speed too low, the header drive having so much friction that the drive system actually pulls it up, too much tension in the header support springs and hay that's too short or insufficient quantity. My 336 can't pick up grass clippings and my 14T can't swallow a completed bale that's in the way and rebale it.
The 14T is a great machine to learn how balers work and whether or not you are cut out to make hay. Its not styled, so you can look at and work on all stations from standing beside it. Knotter and main drive is chain driven so you will have to learn about chains and sprockets. A couple of box wrenches and a grease gun are all it needs for in field service. Its not a CV driveline so some tractors have difficulty towing it and turning. A 4020 seems to be favorite for my 14T. No thrower or kicker though, although an ejector was an option.
A 336 is a styled machine, pretty and a lot of stuff covered up. That means you don't inspect it as often and quite a mess when you have to open her up.
Hydraulic tension, proprionic acid applicator, kicker that can launch bales into low orbit and auto lubricator. Knotter parts interchangable with other balers. A 4430 with cab and Fridgidaire is the only way to go with this train (did I mention an electric hitch to cut loose the bale wagons and pick up 2 more without leaving the cab?)
This guy is on a tight budget, not likely to buy up a 336 and power it up. Best help we can give him should be to get his machine working and functioning. This seems to be a systematic problem on this forum: Don't tell someone you have the wrong equipment, tell them a clever and constructive way to make it work if possible. Sure, I need to buy or hire a 40' crane to put my windmills up. That ain't gonna happen. I used my front end loader and a truck to set them up.
Get the machine lubricated properly; chains working freely, twine disk tension by the book, knotter drive timing correct, tucker finger clearence good, header weight in spec, rpm at 1 stroke per second, bale case tension OK, cutoff knives sharp, wiper arm friction at 10 lbs, billhook jaw pulloff at 10 lbs, twine box pullout at 10 lbs, driveline angles at zero, and hitch height at 16". Then go make some bales.