Max rpm at WOT for that motor is 4200-4600.
Is this a new to you boat? Did it ever work better?
What prop do you have on it?
You may have to prop down to get the rev's up to where they should be at WOT.
If there's an existing wire for something else going from the console to the compartment you could use it to pull a fish wire through and then use the fish wire to pull the original and new wire back.
Welcome, as you have discovered they're hard if not impossible to find.
Your best bet is to get a custom one made from a local canvas/tent/awning shop.
Maybe you're over tightening them?
I've always just hand tightened them and then snugged them up.
I've never used anything on them.
You're not dealing with any pressure to speak of.
Welcome.
A serial number would help as there are 2 possible systems for that era.
A picture of where the leak is would help as well.
Can you describe this "housing"?
Is the pump in the boat or is it part of the motor?