1990 Johnson 200hp can't get to WOT

[Iceboy149]

Guys any ideas on this? I have a 1990 Johnson 200hp Counter Rotating on my 1983 20' Seacraft SF. Anyway I can get up to about 4400rpms and then a short couple of horn bursts. The horn bursts are intermittent, they are not one of hte four characteristic ones, the constant for fuel restriction, overheating, or low or no oil. They happen sporatically every 5-40 seconds apart but only at WOT.

Now at WOT I only get 4400rpms. As I trim up the engine the rpms slowly get up to about 4800rpms as the load decreases (I guess) as the prop nears the surface of the water.

Here is what I have done and the problem still exists:

New Filters, inline and Fuel Water Seperator.
New Fuel ball
New Plugs
Carbs rebuilt last season and winterized.
New Powerpack, Ignition Coils, and Plug Wires
Switched out VRO2 oil/fuel pump with a spare one from a newer engine.
Dismantled VRO Tank and everything looks to be in good working order.

One mechanic told me that there is a temperature relay somewhere near the top of the head on both sides and to try unplugging each one for the sporatic beep.

He also said that on this motor the high speed jets have been known to work themselves back and they need to be tightened and then have new carb bowl screws that have "tangs" on the end installed....these being a new part from Johnson in order to keep the high speed jets in place and to not back out.

Has anyone ever heard of this? And yes I visually inspected the high speed jets to see if there was any debris in them but did not touch them for fear of disrupting them, so I do not know if they are seated correctly.

Any other ideas as to where the loss in about 600-900 rpms is? I'm doing a spark test on thursday again, perhaps one of the new coils went out already?

THANK YOU for your help!