ccarloss

Gentlemen, thanks for the suggestions. Hooked up a mechanical fuel pressure guage and sure enough......fuel pressure was all over the place.....40-20-30-10-20-5-20 etc.

I pulled the boost pump off again and it had a bunch of crap in it again. I never thought that was the problem since I just cleaned it out but I guess there is something in the tank. It is like a brown paper substance that is clogging the screen in the boost pump. I may rig some inline filters before the boost pump until I can get all this crap out of the tank.

Any suggestions on a good inline filter?

Dixie Doug

We used Racor RC-S3228UL AND HAVE NOT HAD ANY PROBLEMS

Escape Velocity

I had the same problem with my "new" 2002 496 Mag HO - boost pump screen filled with junk. I think I found a real promising answer tonight on the Mercury Parts Express website.

Under engine accessories, they list a fuel filter kit that says "Prevents blockage of the boost pump inlet from debris that may be in the fuel tank. This filter is installed in-line between the fuel tank and boost pump. Standard equipment with all current engines using a boost pump. This filter will backfit older Mercruiser 8.1S/496 Mag engines."

The part number is 35-864572A 1. Depending on who you enter as the closest Parts Express dealer, the prices in my area ranged from $84.05 to $110.86. Also, they list a replacement filter, part number 35-864572T. Again, prices varied from $47.70 to $57.24. I'm in a hurry, so will probably pick this up from a local dealer, but BAM in Florida sells these two items for $73.54 and $45.30, respectively.

In addition, I like the idea of using a Racor filter in the normal water separating/fuel filter location, which is after the boost pump. It has a 10 micron filter rating, which is much better than the Mercury filter that has a 25 micron rating.

All these filters are kind of expensive, but well worth it if they eliminate that awful feeling you get when the engine bogs down when you're out on the water.

I'll get my fuel delivery problems resolved so that when Raylar gets his heads/intake/cam/ECM upgrade sorted out I'll be ready!

ccarloss

Thanks for the part numbers gentlemen. Those are rather pricey for an inline filter.......oh that's right........it's Merc.

Here's a question. Can a regular automotive carb inline filter work? Or would it be too restrictive?

Escape Velocity

I'm not qualified to answer the question about an automotive filter, but I thought it was interesting that Mercury includes the Racor brand filters on their parts store website. I take that as a strong endorsement for their product.