Projects and Upgrades

Fuel Polisher

Here is how I installed the Filter Boss “Commander” Fuel Polishing system from KTI Systems, Inc. in an IP420. The first decision was to evaluate mounting locations in the IP420 engine compartment and then choose which version of the Commander series would best suit the available space. I chose the 60GPH version, the smallest.  You can buy it pre-assembled in a “horizontal” version (components pre-mounted on a board to optimize vertical clearance) or a “vertical” version (components pre-mounted to optimize horizontal clearance). You can also buy it as a “modular” system which gives more mounting options for tight spaces. While it would have been nice to be able to use one of the two completely pre-built assemblies, neither of them would fit in any area of the engine compartment and still allow easy access for filter changes and clearance for hose runs. Therefore I opted for the modular version. The folks from KTI Systems at the Annapolis Boat show were very helpful and worked with me in regard to the available space in the IP420 engine room (I had measurements with me). They offered to make a customized mounting with the Commander unit and the fuel pump mounted horizontally on a plastic board and pre-plumbed. The filters themselves were left separate. This was the most optimal way to go as you will see in the pictures below.

I started by removing the previous pump and single filter setup that came with the boat. The sound proofing material on the door had seen better days, so I removed that as well and replaced it with a new piece.

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New sound proofing on door

After “dry-fitting” all the components in several possible places, I decided to mount the custom Commander/pump assembly on the inside of the starboard door to the engine compartment (the galley side in the IP420). I mounted it as far as possible to the upper right side of the door. This way, I had room to mount one of the two Racor filters to the left of the assembly, and would have a good amount of clearance between the bottom of the assembly and top of the engine when the door was closed. This also was the best spot for the subsequent hose runs to the Commander unit. Another decision at this point was what size fuel hose to buy. The boat already had 1/4” fuel lines coming to/from the tank to the previous Racor and then connecting to the engine. All the fuel ports on the Commander are natively 3/8”. I choose to replace all the fuel hose with 3/8’’, except for the hose that supplies the engine itself. This way, I can get a lot more flow when polishing the fuel since the whole route to/from the tank and through the all the Racor and Commander fittings is 3/8”.

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The custom assembly mounted on inside of engine room access door. Both the Commander unit (white) and the fuel pump (grey) came mounted on a thick plastic board and pre-plumbed to each other with metal tubes.

Next, I mounted one of the two Racor filters to the left of the assembly on the door. The mounting position of the filter was carefully chosen so: 1) The filter wouldn’t hit the edge of the door frame when closing the door, 2) It wouldn’t hit or be too close to anything on the engine when the door was fully closed, 3) There wouldn’t be impossible bends in the short hose run between the filter inlet and the Commander outlet ports. Fortunately, there was just barely enough room to satisfy all these criteria.

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One of the two Racor Filters mounted next to the Commander assembly.

If you look at the close-up picture, you can see it was possible to mount the filter close enough to the commander to get a perfectly straight short hose run from the Commander outlet to the filter inlet. To get these two components this close together, it was necessary to cut off part of the metal mounting “ear” on the Racor which was butting up against the Commanders mounting plate and preventing the nice straight hose run. I did have to buy several 90 degree fittings for the Racor ports as well as the Commander ports.

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Close-up of the short straight hose run between the Commander and the Racor enabled by this mounting position.

The only other reasonable place to put the 2nd Racor was on the inside of the other access door on the port side of the engine. Of course, mounting it there meant I had to route the fuel lines across the engine. Rather than go under or around the front of the engine, the shortest path was up and over.

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The 2nd Racor filter mounted on the opposite side access door. You can see the fuel lines going up and over the top of the back wall of the compartment.

This hose routing also made it easier open both access doors fully without the need for a lot of slack fuel line near the door hinges. Note the section of the back wall of the engine compartment with the sound proofing removed. While this area appears to be a potential mounting spot for the Commander assembly itself, that part of the back wall is actually a removable panel on the IP420 (aft side engine access), preventing anything from being mounted on it.

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Here you can see better how the lines are routed to the 2nd Racor and also what it looks like with that aft access panel removed (mentioned previously).
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Back at the starboard side, here is how all the fuel lines come up to the Commander. In addition to the 2 lines from the 2nd Racor coming in from the top, the line to the engine and the supply and return lines from the tank come up from the bottom.
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A closer look at the hose connections to the Commander. In order to get adequate clearance above the engine, I had to install a right angle fitting for the tank return line coming off the bottom front of the Commander.
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Here is what it looks like from the inside of the engine compartment with the access door closed. You can see there is good clearance between the bottom of the Commander and the top of the engine.
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Looking into the engine compartment from the front with both filters in place and both access doors closed. Sound proofing is back in place on the aft access panel as well.

Everything worked just fine and I had no leaks. I did have to fill the distant Racor with diesel first as the pump could not self prime it like it was able to do for the closer Racor.

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