omc stringer 800 wont shift into forward

hello,
I have a 1974 slickcraft with a omc stringer 800 electric shift outdrive with 265 horse motor. The problem is i cannot shift into forward but it will let me shift into reverse. I have checked the wires that run into the lower unit with my meter and im getting 12 volts when I move the shifter to forward and reverse. I also checked ohms and I got 6.1 on either wire but I hear no click in the outdrive when i shift to forward from neutral or from neutralto reverse. Is it possibly a bad coil or spring perhaps? Does anyone know where I can get step by step instuctions to tear down the lower unit to get at the coils. thank you to everyone that could possibly help and could have some input on this because i am totally lost and have searched the internet high and low for info on this boat. thanks again

ive also included some pics of the outdrive and control box if that helps anyone

if you have 6.1 ohms, and 12V is being supplied, you certainly do not have a bad coil. You have some sort of mechanical issue with the drive - broken spring or something else physically preventing engagement, and therefore a "click" in the lower unit in F.
Just for clarification and parts ordering/manuals etc., your drive is not an 800 series. It is electric shift and all electric shift units, although there were several different models, were simply called the "OMC Sterndrive" by OMC from 1964-1977. The 800 series was introduced in 1978 and was cable shifted.

You might try ebay for repair manuals. I bought a disc with a manual on it for cheap.