Pete6114 - First, some disclaimers:
1) If your warranty isn't already gone, it will be if you up the pressure on your hydraulic system. I doubt it would adversely effect the engine warranty overall, but if you broke the shaft that drives the pump, forget it. If you burn up the pump or have any trouble with any other part of the hydraulic system, forget it.
2) Everything I know (or think I know) specifically applies to the L-series only, or is presented as theory only.
3) The cylinders on your tractor most likely have a maximum rating equivalent or very close to the maximum pressure setting on your pump, so if you up the pressure put out by the pump, expect cylinder failures or, at the very least, leakage.
4) Generally speaking, your tractor is designed around a set of parameters that are pretty well balanced. If you monkey with something, you can expect that you'll break or bend something sooner or later or, at the very least, wear out friction points a lot faster.
5) Everything you've ever heard or read about safety should be magnified 100 fold if you up the work limits of your tractor. If you aren't 100% aware of the limits of your equipment and an experienced operator, you're greatly increasing the chances that you'll hurt or kill yourself, and should get to the point where you're both before increasing the capabilities of your machine beyond its design limits.
6) There have been cases where people increased the pressure of their tractor hydraulics and the 3-point-hitch lift cylinder piston blew completely out of the rear axle case, destroying the case, the cylinder and, in at least one instance, injuring the operator.
7) Knowledge is power - we all know that, but we sometimes forget that it's often the power to get yourself in trouble.
Now, if you're still with me, and you still want to up the pressure of your hydraulic pump, read on.
The pressure of the pump (remember that I'm talking about the L-series in particular, but I'm pretty sure the B-series works the same way) is controlled by a pressure relief valve. This valve is a very simple one - it's just a ball valve with a spring. You increase the relief pressure by adding shims between the spring and the cap. You
must have a gauge to check the pressure. I think you should never under any circumstances increase the relief valve setting more than 10%, if you increase it at all. You're going to need to get a shop manual, if you don't already have one, in order to find the valve, too, unless somebody else here can tell you.
Lastly, one more disclaimer: Just because you know how to do something, or know somebody else crazy enough to do it, doesn't mean you should, too. If you tear something up, you were warned. And if you do it, it might be best if you don't tell anybody. /w3tcompact/icons/wink.gif But, whatever you do, please don't interpret my telling you that it can be done as an endorsement of your doing it./w3tcompact/icons/smile.gif
MarkC