Mariner 175 Wont Rev in Gear

Hey guys - newbie here,
I got an 88 Champion with a 175 Mariner, just replaced throttle tower and a bunch of little items.
Put the boat in the water yesterday... no leaks!!

But the motor will rev fine in neutral, put it in gear no problems, but when I start to gas it up it will go to about 2k rpm max... it then wants to stall.
I can pull the throttle back and idle around fine.

While the boat was moving I got back and manually moved the throttle body and it did the same thing ... it slowly tries to rev but then starts to stall.
If I leave it in high throttle, it will stall out.

Timing?

Anyone know where there are some online pictures of this motor so I can see if I am missing some kind of timing advance mechanism.

Hard to test this repair out of the water, and my nearest lake is an hour away.

Re: Mariner 175 Wont Rev in Gear

No replies yet but more info:

The motor will not rev past 2k rpm under a load.

New spark plugs

Jets clean and proper size

I tried manually moving the timing advance arm while under load... advance/retard only bogged.

Gas lines are clear, ball firm.

Just got shocked 6 times running the boat in a tub.. not under load but idling.

When I am in the lake and move the throttle forward in gear the RPMs do not jump around at all... only a rapid bog that will kill the engine if I leave it there for 4 to 5 seconds. No sign of life.

Any test suggestions?