Oil pump prime

It would be hard to do with a tractor engine, but on car and pickup engines, I check the oil pressure while the engine is still on the engine stand.

I plug an oil pressure guage into the oil gallery on the engine. Then on an engine with a distributor driving the oil pump, I chuck an old distributor shaft into an electric drill, reach into the distributor hole and spin the pump until pressure comes up. On a computerized V6 without this option, I have an old, humongous 1/2 inch electric drill that will actually spin a fresh V6, without spark plugs, 400 to 500 rpm till pressure comes up. Either way pre-lubes the engine so pressure is right there when it fires.

I just don't like surprises after I've installed an engine.

I would think on a tractor, with no spark plugs and a healthy starter and battery, the starter would spin the engine fast enough for pressure to come up.

Since the plugs were already out, I changed the oil, put on a new oil filter (filled it with oil before installing), then used the starter intermittently to spin the engine until the oil pressure came up.

I used the starter only a couple seconds at a time until the pressure gage started moving, then when the pressure was up, I ran the starter for 10 to 20 seconds at a time.

Once I had good pressure, I reinstalled the plugs, and started the engine, and let it warm up, and then shut it off, and repeated several times.

Maybe overkill, but that is what I did.

Others may have better advice, good luck