92 VX250 mid range hesitation/bogging

All,
This is a low hours 92TXRQ. I have rebuilt all 6 carbs, replaced the three pulse fuel pumps, no anti-syphon valve in main tank. Have hooked up an auxillary tank and symptoms are exactly the same. Bulb remains stiff during the bogging. Fuel filter bowl on engine reamains 3/4 full during bogging. The engine idles smoothly and will run fine above 4500 and revs to 5400 rpm. It accelerates smoothly and has gobs of power but will not remain at a set RPM below 4500. It has the little electric pump for priming and I believe it is not functioning as cold starts are rough but after warming, engine idles fine. Could the electric pump be the cause of the mid range issue? I have eliminated fuel quality and delivery to the fuel filter as an issue. I even removed the check valve between the carbs and the fuel filter but no difference. I have read other posts and no one has been familiar with the electric prime, manual pump system enough to make suggestions. Any ideas? Before spend the 200.00 for the pump and regulator, can someone verify if this supplies the fuel system other than for cold starts? The Clymer manual is useless. The manual did state that Yamaha has found that the fuel lines could be kinked on this model and result in top end loss of RPM, but this does not fit that pattern as the 92 Aquasport 215 WA will travel 45mph at WOT. Any help would be appreciated.

[pjw]

I have a 225 with that primer pump on it. I also have the shop manual. It says to put a slight vacuum on it and if you don't lose the vacuum for 10 seconds, the diaphragm is ok. There are also 2 electronic solenoids that control it. They're used solely for enrichment instead of a choke. You can bypass it by pulling up the little red lever if you think the solenoids aren't working. I also have a posting on this site - my 225 has hesitation between 1000 & 2000 RPM's. Everything else is fine. I replaced the fuel pumps but that didn't help. I'm leaning towards rebuilding the carbs. I've been wondering if that pump could be causing my problems, but I don't see how. Mechanics have been telling me that they've been taking off the bowls on the carbs and the majority of them have been eaten away by the ethanol and that's been causing acceleration problems. Let me know if you find out anything--it might help my problem

All,
Thanks for the advice. The problem is fixed!!! By getting a "real" manual, I followed the process for adjusting the linkages.(4 rods are interconnected to the 2 main rods for the 6 carb butterflies...whew..)All was found to be within the spec, but when I opened the throttle fully with the 704 lever, the port side butterflies were only 3/4 open...Hmm. Upon further investigation, I found that the hose clamps(real clamps, not wire ties) were interfering with the full opening. This also must have been holding the timing advance sensor on the top carb so when it went up to mid rpms, the advance setting was way off for the rpms and created a knock on the port side bank that caused it to reduce rpms. Whacky but true. There is a reason why Yamaha uses the wire ties on the fuel lines. I repositioned the clamps and now I have my engine back! The primer pump turned out to be bad, so I sprung for the 182.00 and replaced it and now it starts like it is fuel injected.(It kinda is for cold starts). A quick tip on the primer pump...the forward bolt is 10mm, the aft hold down bolt is 12mm. Given that you can barely see the rear bolt, useful info. Also, if you don't hear the pump sound when you turn the key on, it is not working.