I have removed the four bolts and spacer that connect the engine to the lower unit and loosened the two bolts at the front of the clutch but the engine will not lift off. Any ideas?

Don't you have to remove the clutch to get the motor off?

Got to get it separated from the lower unit first!

Try some blocks of wood and pry bar on each side at the same time

I tried pulling up with a come along and used a pry bar but still would not move.

Is there a more detailed manual available for the Prodrive lower unit. Not knowing how this all fits together isn't helping. How does the shaft from the engine fit into the clutch assembly. Presumably there must be a key way ? If so then it should just pull apart.

No there is not. The only thing holding the engine to the LU after removing the 4 large bolts is the shaft being frozen inside the clutch coupler. Soak with some type of penetrating oil. If you shoot some into the 2 locking holes on the side of the clutch coupler it will make it way to the shaft. The coupler bolts to the clutch and the LU drive shaft is splined and slides into the bottom of the coupler. After the soaking try some wedges to seperate the 2. But for what its worth I had to cut my first one off with a sawzall at about 8 months old. Again, thats why I advocate tearing down the LU every year to re-grease and apply some never seize to every thing. You wait any length of time and your likey to have issues. It makes a world of difference when you remove all the old hardened grease and apply a fresh coat to the LU tower and reverse assy. There is no keyway.

Thanks. I will try that.

Try to do it exactly like poker1 described. I wouldn't try to lift the motor off with shear force, you can separate the clutch and then you'll be replacing a clutch. Use penetrating oil and wedges or prybars, try prying between the motor and the clutch and see if you can "lift" the motor off the clutch that way. Just be sure to have the motor supported otherwise when it comes off it will end up on the floor.