Nice looking sled
What RPM are you turing when it starts to cough? I do not see how needing you pump rebuilt would make the motor cough it could limit your speed but not that bad unless it was a total POS. When the pump is wore out the motor will make a lot of noise i.e rpm's will go up but you will not be moving to fast from the slippage in the pump? A little more info is needed to help steer you in the right direction.

Thanks, well my RPM/temp/oil gauges don't work  the speedometer and fuel are the only ones that work  so there's another issue I need to work on, getting my gauges to work . It is equipped with MSD ignition, and Wilkes told me my alternator belt is too big therefore will slip at high RPM which does not create enough current that the MSD requires, so that was one of the "minor fixes" (right size alternator belt, secure battery better than it is, check distributor cap for corrosion).  As far as the pump he said my wear ring may be worn out so since that would be replaced that I should just do a rebuild(quoted at roughly$750-$1000 parts and labor).

The two gauges you really do not need work that bites. You really need the Tach/temp/and oil pressue to work. They are your motor's life line. I would fix them asap and then take it for a spin and see what the motor is doing.
Since the tach is not working what does the motor sound like at 25/30?? lots of rpm or not so much? The pump is an issue possibilty (most likely) it is a jet boat and often over looked by alot of people. Remember the power is in the pump

Another thing I noticed was the registration sticker   05    Has it been sitting that long   How was the fuel in the tanks, and did ya use old fuel Just an observation

The stickers on the boat are 05 but they actually came with 09's I just didn't put them on yet, the previous owner said he took the boat out last season and it ran fine, so according to him I would say the boat sat 1 season. We actually did a oil change on the boat before we took it out and the old oil was milky but since it was changed oil looked fine. As far as fuel it was kind of empty when we got it and we ran about 2 full tanks through it already (about 20gallons tank). I'm new to boats but the RPMS do not sound EXTREMELY high sounded kind of normal. First time we took it out to Elsinore and it seemed okay with 30mph max and coughed at wide open throttle(also with 2 people) from 30seconds to 1minute intervals , then the second time at the river it ran maybe 17-25mph(with 4 people) and coughing at maybe 80% to 100% open throttle with 2 second intervals between coughs.

Cough as in a pop through the carb?
Could be thrash in the carb and time for a rebuild on it or or or your cam is going flat? Not the best mechanic here so maybe some with more expertise can pick up here. 

Thanks for replying,
Not so much a pop but literally sounds like a cough that a machine would make but it can possibly be from the carbs

djthicks, i have seen that boat before. this dude that used to sell me crack pulled up with that thing on a trailer a couple of times. should have gotten a weed wacker.

hmmm interesting 

any luck with your boat?

not yet BUT i just sold my truck so I will have $ for the boat.... but how do i tow the boat with no truck now??? hmmm???

you done screwed up on that deal

lol well if you see any good deals on a 2500HD diesel for around $13k let me know