I am replacing the belts on my 97 baja hjammer. I noticed the fuel pump pulley is very hard to turn w/o the belt on it. I checked the oil level and it smells and looks like there is gas in the oil. Is it normal for there to be so much resistance on that pulley.

yes there is quite a bit of resistance there from the fuel pump and the impeller. but if you smell fuel in the resevoir you probably have a leak in the fuel pump diaphragm. Is there any fuel in the clear line coming from the pump, if there is then the pump definately has a bad diaphragm. Hope this helps.

If there is does that mean the pump is shot? The boat seems to run fine. I am replacing the belts because the altenator belt broke.

More than likely you are fine. That is a common condition of the sea water/fuel pump. If the pump diaphram was bad, the oil level would be higher, along with gas in the sight tube. Don't know if fuel actually gets into the oil or just the fumes, but the oil does smell of gas and gets a thinning feel to it over time, but the level never seems to raise any. My 'thought' has been that trace amounts of fuel will/can seep thru the diaphram over time as I believe the rubber is not a solid material, but has very very very fine pores to make it pliable. At least that's my story.
I replaced mine with a new fuel pump when I 1st noticed this same condition also. A month later while doing a following up, the odor was back. Just the nature of the beast. I just changed the oil twice a yr from then on so the seals would not get ruined from the thinned oil as a precautionary measure. Never had a problem.

How do you change out the oil in the fuel pump? Also, is there some sort of tension control on the fuel pump belt or do you just pull it up over that plastic pulley when replacing it?

Some have 2 fill screws on the side of the fuel pump mounting. Lower for draining. I always just removed the fuel pump and soaked up oil with a rag as it gets all the oil out, and then refill thru the top opening until flush with top fill screw before reinstalling the fuel pump.

Thanks man, I removed the pump and the oil is very thin from fuel getting in there. The pulley is still very hard to turn even with the fuel pump off. Do you think the sea water pump needs to be replaced or is that normal for that kind of resistance to turn the impeller.

That resistance is normal because of the impellor.