OK...got out despite the rain today and found all four rear cylinders on both engines are still making the plugs run solid black. Still showing no color on front 4 cylinders. Switching to the 8.5 power valves from the 6.5 that came with the carbs did not clean anything up so I switched all of them back to the 6.5 power valves. Vacuum guage from summit has not yet arrived, and the hex plug on intake of one of the engines still will not come out. Can I go down to 4.5 power valves on the primaries to try to get fuel to the front 4 cylinders and leave the 6.5 on the secondaries, or even switch them up to 8.5 to lean out the secondaries? I'm still running #86 jets on all four corners of the carbs.

If you have a carb spacer, you could drill and tap it. If not, installing a carb space would be a lot easier than taking your intake off.

If you are using the old power valves throw them away & get new ones. I would say use 4.5 all the way around. Of course we will not know until we find out what vacuums the motor has at idle & under loads at different RPM's. Is the guy that rebuilt your motors a car guy or a boat guy? I have found that alot of the car guys do not understand the loads that boats put on motors & will give you all kinds of incorrect info. I am assuming you have adjusted floats already, just below the sight opening?

f302, you have the concept backwards. 8.5's are in effect richer than 4.5's because they open sooner. The number on the power valve refers to the atmospheric pressure in inches of mercury when they open. 4.5 is a good number for boats.

Change your oil if you are puddling that much fuel!

However,I don't think changing from a 6.5 to a 4.5 will make that much of a difference. Something else is still wrong.

OK...my engine guy is a car guy I must admit....however I think I've just stumbled on the problem....I'm using a square bore 4150 carb on a quadrajet alum mercruiser intake designed for a spread bore but with both bolt patterns for the studs. I have a summit linkage plate below the carbs with a square bore pattern on it and it hid the ridiculously different pattern of the spread bore intake from my view. It looks like lots of dead zones for velocity and fuel atomization below this combination. I did'nt know there was an adapter plate available or necessary for this....but I ordered two new sportsman II intakes from merlin today that are designed for the 4150 carbs. I've heard pros and cons about the adapter plates..so I took the easy way out and went for the new intakes at $215 each from Bill Mitchell Hardcore. Unfortunately by the time they get here, I paint them, and return from a quick vacation I won't be able to post the results till about 2 weeks from now...but I'm anticipating a huge positive difference. If its not....I'll sure be back on my hands and knees begging for more advice. Thanks to everyone...having that many people telling me that something is severely wrong caused me to did deeper for a problem instead of just playing with just more fine tuning float and jet adjustments etc. I'm just hoping the intakes correct it.....don't be afraid to tell me if I'm on the right or wrong track. Thanks again to all... Glenn

BINGO anyone! Back to square one.