You need a high pressure tester and an adapter to get into the injector holes in the head. Check out neroks link to a service manual download. I would suggest that you leave the compression test to someone else to do, real easy to stuff up big time.
1) cracked spill pipes when the injector turns while undoing injector lines.
2) when putting injector pipes back on minor damage to fitting which will need to be lapped in to seal again.
3) Copper washes under the spill pipes may not seal after re-tensioning.
That's just a few off the top, factor in $200 for compression tester and if you want an adapter for an SD33 there less common than rocking horse manure!
Someone else on the forum may know what it would cost for a compression test.
For little jobs that may improve things and let you get your teeth into something.
1) Remove rocker cover and check tappets they will probably need doing and while your at it clean out the breather and all the gunk from the cover. (If your careful you wont need a new gasket its rubber)
Drain the fuel tank it may have 25 years of sediment in it.
2) Replace oil and fuel filters and oil. (run some flush in the oil for a short time first)
3) Clean out the filter screen in the banjo where the fuel goes into the fuel pump.
All the above details are in the manual. Have fun with your troll
