OX66 250 HP Fuel Problem

[Gill7858]

Hi all, I have a 2002 OX66 saltwater series 250 HP 2 stroke. Heres my problem: from cold start it takes an excessively long time to crank and the PRIMER BULB goes soft. After cranking it 7 or so times she starts up. When idling, it has no problems but when I start to throttle up it starts to sputter as if its not sucking in enough fuel(through the 1500 to 2800 RPM area), however once i gun it, it powers up and it runs just fine. If i try to keep it within the 1500-2800 RPM range it sputters. She doesnt turn off but definately doesnt run as she should.
It being direct inject. Im not sure of the primer bulb is suppose to stay hard or not. I changed out the primer bulb just in case and had no effect. I was told that these engines have three fuel pumps high and low pressure, so just thinking logically Im guessing one (or multiple) of them could be the problem. The VST tank was cleaned and serviced less than a month ago so I know thats good. The only other thing I can think of is an obstruction in one of the fuel lines. In either case, if it is the pumps how difficult are they to replace? a step by step would be extremely helpful. especially if there is a way to test the pumps in order to see if they area working properly.

Thanks in advance for any input.

[99yam40]

monitor fuel pressures, if they stay in spec while problem is occurring then maybe injectors.
either way the laptop should show if there are other problems also, probably need to get it hooked up to one

[Gill7858]

Is the primer bulb suppose to remain hard?

[99yam40]

being on the suction side of pumps they will not stay hard, but should stay full of fuel and not go flat

[Gill7858]

ok so if it does go flat(which it does), what can be the problem? should I change out the fuel lines? can it still be the LO or HP fuel pumps?

[jb123]

run on an aux tank hose and ball hooked to motor filter to isolate issue
note level of motor filter when it wont start, if low it will suck air
your pickup tube may have a screen or check valve which you should remove
also bypass or replace the check valve next to low pressure pumps as they can seize

[rchancew71]

My understanding is

between 1700 and 1900 rpm the motor switches between 4 and 6 cylinders running. At idle the motor runs off less cylinders. The motor will seem to miss in this range. Your problem persists up to 2500rpm so this is only a guess.