2001 250 OX66 lp fuel pump

One engines rpm was fluctuating at cruising speed. checking over the motor I found the primer bulb was not getting hard. With a pair of needle nose pliers I narrowed the leak down to the middle low pressure pump.
Can it be unbolted without taking off the HP pump & VST?
Also I noticed some
unburnt gasoline coming out of the exhaust at times. I can't figure that out.
After doing a search it seems like the oxygen sensor. Does that sound right?
Steve

[jb123]

a bad diaphram in a lp pump will cause rough running AND unspent gas out of exhaust. not sure on the large bore v-6's but the smaller you CAN pull lp pumps off without HP removal.

if you unhook the hoses to the lp's, you can blow thru them.....up/w/flow should allow air to pass but blowing DOWN should NOT allow any to pass... if in doubt, theyre cheap enuf to change out.

also: http://www.boatsetup.com/O2sensor.pdf

[TCSavage]

OX 66 250 engine lp pumps can be replaced without removing ether the VST or hp pump. If it hasn't been done, you might seriously consider replacing all 3 lp pumps. Every three years is recommended.

[Captain Bill]

I had the same problem, and replaced the pump, if all pumps need to be replaced (I think they are around 36 dollars per one) can you just buy the gaskets and rebuild them. In looking at all the service manuals I don’t see that the fuel pumps need to replaced every three years. Where is this written.

Thanks guys. I'll swap out all 3. I'll let you know how it turns out.
Steve