opening the control box to my 73 115hp Johnson

I'm trying to get into the control box of my 73 115 Johnson. I've removed the bottom plate (cover) and removed the black cushion from the top. I've also removed the throttle lever and warm-up lever, but I cannot get the top/front cover to budge. What steps do I need to take to remove this panel so I can get full access into the control box.

I'm trying to access the box for a few reasons: The previous owner cut the choke toggle wires within the box and conected the choke solenoid to the ignition so that when the key is turtned the choke is initiated. I would like to connect the toggle switch back to the choke. I would also like to check my tachometer connection. Apparently I disconnected something while installing a new fishfinder (I don't think the problem is in the control box but I'd like to check it if I'm in there. I would also like to clean-out a dirt dobbers nest thats within the box.

Any suggestions?

Re: opening the control box to my 73 115hp Johnson

There are three hex head bolts that hold the box onto the boat. You can see them with the lower cover removed.

Remove the box from the boat. Once you can see the back side, you'll see three large phillips head screws that hold the cover on.

Re: opening the control box to my 73 115hp Johnson

So you have to remove the box from the boat before you can remove the top front cover?

How can I check to see if the horn still works and is connected correctly?

Re: opening the control box to my 73 115hp Johnson

Disconnect the tan wire from the sender at the engine and ground it to the block with the key in the on position:

The horn should sound.

To test the sender itself requires that it be removed from behind the cylinder head cover and heated in oil while reading with a test light and thermometer. It should close at around 210 degrees F, and reopen at around 175.