1999 Johnson 200 J200PXEEN will not go past 4850 at WOT

I recently took over my fathers 23 foot open I recently took over my fathers 23 foot open fisherman which had been sitting for three years. 1999 Johnson 200 J200PXEEN I removed all gas replaced fuel filter water separator and noon Champion spark plugs gapped at .030
starts and runs great however I can’t get to wide open throttle it will stop at 4850. after further inspection I noticed my for throttle timming Advanced screw was loose and probably backed out or in. VRO pump is bypass and I mix 50:1
I just purchased a fuel pump rebuild kit all OEM as well. I’m going to rebuild it before I go out this weekend and I borrowed a friends test prop so I can perform the proper timing procedure has anybody else had similar issues is the timing that critical to where I could lower my RPMs that much?
Thanks in advance
I am also going to bring out a test tank this weekend so I can bypass if I have a fuel pick up problem in the tank

You might be able to see a paint or discolored mark on the timing advance screw to determine were it was and if it looks like it has moved, follow what ever procedures it calls for checking the timing and made sure you get plenty flow from the tank to motor with no air leaks. It don't take long to score a piston do to, to much timing and/or lack of fuel. check compression often see if there is damage now and after all of the trouble shooting. good luck.

I actually just verified the timing was only advancing 8° I am now set to 18° it also looks like it’s running too rich but 10° off on full throttle timing is a nice amount so I’m gonna see how she does tomorrow on the water