Re: 175 rude, 1989, bogging
It is evident to me that you have a fuel or intake issue. The question is the use if the primer simply giving it the fuel it needs or is it compensating for not enough fuel? Probably the later of the 2 since it is running out of gear.
Did you check for intake leaks? I use a propane torch (without the flame). Check around all fittings that lead into the crank case or carb. I'd also check around the engine block, is it possible there is a crack? If there is a leak, propane will find it. Obviously, use a lot of caution.
Can you take the air silencer off and watch down the carb throats to see if fuel is coming out the main jet and slow jet circuits?
I am pretty sure that this solenoid fuel circuit totally bypasses the carburetors. In fact, from my service manual: ?Mixture enrichment for cold starting is controlled by a fuel primer solenoid. When activating at the key switch, the solenoid diverts some VRO pump output directly to the intake manifolds?. So you can't rule out the carbs just because the primer is working.
A friend of mine had bogging issues with a 30hp Nissan. The slow jet circuit went from the bow of the carburetor up to the top of the carb where there was a chamber then down to the mixture screw then into the venturi. There was a "plug" or "cap" at the top of the carburetor at the chamber. It ended up that that chamber was totally clogged, furthermore the plug was leaking. I found the leak after spraying carb cleaner into the circuit then blowing compressed air through it. I ended up boiling the carb in water and a little bit of chlorine for about an hour (old trick I learned a long time ago). I then sealed the plug with high heat silicone. He said to go for it because he had nothing to lose, he was at his wits end and we really just wanted to go fishing. If that did not work, he was just going to put the $270 out for a bran new carburetor. Well the boil cleared out the circuits and the silicone has held for about 2 years now and the motor runs as he remembers when brand new. Now I am not saying to boil your carbs (unless you all else has failed). However, you should spray carb cleaner through all the circuits to verify the circuits are truly cleared.
I am not sure these OMC outboards have a gear shift operated circuit interrupter like merc I/Os did. If it does, have you checked that?
I still think the reeds are a possibility.
Just throwing my thoughts out there to give you food for thought.
