they are pushing them big time for high H/P and EFI setups, I have stayed with either aeromotive or magna fuel setups, no issues with either, I think the oems started in tank pumps for ease of packaging, one draw back is that fuel in the tank is used to cool the pump, so if people continue to run at low fuel levels a lot..pumps fail.

Walbro makes some decent in tank pumps for big hp apps. They draw less current than the aeromotive and big holley units . Run one of the large sock pre filters, and a delco secondary, should never have to worry about pulling the bowls or needle valves on a holley for years. Cleans up the engine room a bit also. But def not a plug and play proposition.

The Holley Hydromat would be a great pick-up solution for V bottom boats: https://www.holley.com/products/fuel_systems/hydramat/
I think the in-tank system is a great idea and I would do it right now, but I feel a little uncomfortable about how to rig a water/fuel separator on the pressure side...any ideas? There are USA made, hi-flow, good quality in tank pumps available. Another reason the in-tank set up appeals to me is that its easier doing a complete engine overhaul than changing out one of Merc's block mounted, cool fuel pumps!!!

I ran the Permacool fuel filter/water psi separator at 60+psi for years. And I can attest it separated water. Got a bunch once.

I would think any of the spin on's can handle a good amt of psi as they are set up like oil filters and as we know they all handle a lot of psi.

Edit in: Napa sells Wix Fuel/water seperator spin on's. You could always get an aftmkt spin on base and get the appropriate Wix. Just one of many ideas.

Thanks SB- I just looked at the Permacool 81794 and it takes 90 psi...I guess I have been in the dark this whole time thinking I had to use one of little AC/Delo metal filters like the HP500efi used, but its fuel/water separator was low pressure being before the block mounted pump. Thanks for the heads up.

I'm running my seperators on the pressure side.

this looks pretty easy: https://www.holley.com/products/fuel...s/parts/12-132

FWIW

http://www.mastercraft.com/teamtalk/...ad.php?t=25783

Thanks for the link BUP. I'm not going to read 800 posts, but that system seems overly complex to me and a closer cousin to an automotive system. I would say that in-tank pumps (that are of quality) have shown to be at least as reliable as their external pump counter parts. I have never had the pleasure of replacing an in-tank pump on an auto, but I have replaced the external Merc one on a boat in 100 degrees and I can tell ya, I would have gave a couple thousand at the time to just lift an access port on the floor and have the pump within easy reach!! Not only that, but a high % of boaters in warmer climes will have occasional issues with hot starting. If the in-tank pump ever does shoot craps, you can pick up a cheapy anywhere and still be on the water at least. Many of the small marinas are not likely to carry the right external pump if any and its going to be $$$

The off road guys have run alot of r and d on these. Lots of water exposure,,vibration and impact ect.
I think for them it is dealing with vapor lock on high hp holley carb aps more than anything, that steers them to the in tank route