Just to verify...
When idling, after warmed up, if you press the key in and hold it, the engine should stall. Does it? If not, it is possible that the primer system may seem to be working, but that the fuel is being stopped at the nozzles in the intake where the fuel actually enters the motor.
Just a thought to consider, especially if you have NO DIFFERENCE in running when you press the key in.
That NO DIFFERENCE statement is odd.
OK, so you are bogging on takeoff on this V6 looper....same motor I have worked on dozens of times. Hmmmmmm....
You will need to dig deeper I guess. Compression numbers, proper spark test results, and timing at idle would be nice to know. Compression should be 90-100 within 10% and running timing at idle should be in the vicinity of 4* ATDC.
Double check with timing light that all cylinders have spark when running. Look into the light. Be very critical and watch for irregularities, skipped flashes, etc. Compare all six. They should be the same.
With engine off, disconnect throttle cable, and manually advance the throttle to WOT. Observe the operation of the linkages. Pay special attention to the black tube like assembly under the flywheel, stbd side, and the timerbase that is attached to it. The timerbase should rotate slowly and smoothly counter-clockwise as you move the throttle lever, with no sticking, and as you come back to idle stop position, the timer base should also return (clockwise) to it's starting location.
If the timerbase is sticking, you will not have enough spark advance when throttling up, and the engine will bog. Maybe your timerbase is rotating, but very slowly in old dried grease...and when you throttle up, it is very slow to rotate but eventually does.
If you suspect the engine is too lean at 6 turns out, why not try 7 turns out? You cannot hurt a thing. When you get to 10 turns out, there is no more effect, as the needle tip is all the way out of the adjustment pocket at that point. But try it. You will notice that at 7 maybe 8 turns out, when you shut the engine off, and lower the motor, it will drip unburned fuel out of the prop. That will definitely happen. If you are in a tank, you will quickly develop a large oil slick on top of the water in the tank. These are signs that the engine is too rich.
This engine IS a correct engine isn't it? No weird mods, no swapped carbs trying to get a 225 out of a 200....stuff like that? Anybody play with the jets?
By memory, the idle bleed jet in the front should be a #27, and the HS jet in the bowl should be a #65D. If you had those carbs completely apart as you suggest, then those jet numbers will be in your mind.....
How many screws hold the throttle butterfly to the throttle shaft? Look down carb throat...it will be either two, or three.
And your link and sync......YOU MUST DO A LINK AND SYNC whenever you have the throttle bodies off.......all carb butterflies are absolutely closed at idle, right? The throttle pickup roller is maybe .005 away from the cam it rolls on, and the roller is in alignment with the raised mark on the cam ....right? You have to pay special attention to the butterflies for #5 and #6 due to that connector link used to link the upper throttle body to the lower throttle body. Takes me about 1 hour to absolutely verify the butterflies are absolutely closed. I tap on them, flip the mechanism...tap some more....do each side separately...and then attach the top link....flip the mech again....tap some more.....takes me a while.
Sometimes they behave well, and just come right in to sync. Others are a pain, with one side sticking open, or #5 and #6 being troublesome to get to close right.
