That system needs to be bled! Doesn't anyone paint those parts before installing them? The lower cylinders use longer rubber bushings that might be still available from a Mercury dealer.
The manual I have (1975-1978) only shows the instructions I've posted but on further inspection I notice that it's for up to serial Nr. 4576236 the posted picture is for ser. Nr 4576237 and above, so much for downloaded manuals!
I'm scanning the hard copy now.
This is what I have from the 75-78 manual, I don't think there's a shoulder anywhere at the bottom or top of the housing. Removal is easy; installation is trickier.
You need an Alternator Driven Tach that connects to one of the yellow leads from the alternator, this is the standard tach today. They sell some on this site
https://ww2.iboats.com/Boat-Tachometers/dm/view_id.248010
I went to a Merc dealer and got a "pull" for a few dollars 20 yrs. ago and It's...
Take the cowlings off and look for a distributor and coil/switchbox. I have the wiring diagram for the 77 which uses the distributor but not a diagram for the red band (69-70)?
Is the throttle plate opening all the way up, while engine is not running turn the tiller handle all the way and look into the carb; the edge of the plate should be facing you. Another possibility is the ignition timing is over-advanced which will slow it down. The carb has a fixed hi-speed jet...
If you are using the original fuel tank there might be crud plugging the filter. undo the screws that hold the assembly to the tank and check to see if it's clear. Any Merc was designed to run full throttle for hours.
I have used the steel insert and it went well but you have to use Loctite to hold it in. It seemed to be better than a Helicoil as it gives a complete steel plug hole.
I think it's thick splined washer, prop, castle front thrust washer, then nut, there should be no play in the prop, unfortunately the seals in the casing have been damaged so exhaust could leak out around the prop - PO was a real loser!
It's a limit switch that you can set to stop the trimming before the motor over revs
you set the small bracket on the side to stop it when you've found the right trim setting. Test it in the water on plane.
