Polishing Filter

[GregH]

I am installing a polishing filter between the mechanical fuel pump and the carb finally.

1/ does it matter what type of inline small filter? Would the Scepter ones meant for OB work ok? (ex. https://www.walmart.com/ip/Scepter-0...lters/55583666) Does anyone have an idea why it says in their catalogue for outboard use only?

2/ the line from the pump to the carb is currently copper tube. I found the connection size for the fuel pump on here (1/4" NPT); is the carb the same?

[romantic comedy]

The guys here will tell you more specifics, but I am pretty sure that only metal case filters are allowed below deck according to ABYC.

The one in the link is glass and only for above decks.

[Marty Levenson]

microns

The other issue is the micron size: you want 7-10 microns. Our host or NAPA.

[GregH]

Right! Makes so much sense in hindsight

Are the metal ones throw away or can you get replacement filters?

[Marty Levenson]

one unit

"Product No. - FPMP_07.1_473
Fuel filter, inline secondary (polishing filter)

This is a 7-10 micron filter intended to be used as a replacement filter for our MMI inline fuel filter kit. "

Above is the description in the Moyer online catalog. It is single unit - you should replace the whole thing every year or two, depending on usage.

[JOHN COOKSON]

Do you have a fuel pressure gauge after the filter before the carburetor?
If you don't this would be an excellent time to install one. It will end a lot of guessing.

TRUE GRIT

[GregH]

Not yet. Just any fuel pressure gauge?

Is there a specific post that talks about how to install one? No luck searching on here so far.

[Peter]

Greg,

You need to be a little careful in selecting the gauge. Many automotive gauges are made of plastic and are not approved for marine use as they would melt in a fire.

Metal gauges such as this one

http://www.ebay.ca/itm/Mr-Gasket-1561-1-1-2-Fuel-Pressure-Gauge-0-15-Psi-Non-Liquid-Filled-/322346152260?hash=item4b0d53f144:g:oAAAAOSwgY9XfBBh&vxp=mtr

Are preferred.

They install "in-line" by adding a tee-fitting (which often comes with the gauge) into the fue line.

They are a very valuable trouble-shooting tool.

I first installed one to trouble shoot a situation where my engine suddenly would only run on full choke. (I was going to post a question on the forum about this problem and realized that the first question would be "Do you have a fuel pressure gauge?" So I installed one first!)

Had crappy fuel pressure when I installed the gauge. I then rigged up a jerry can directly to the fuel pump, by-passing the filters and had good fuel pressure. Cleaned tank, changed filters and all was well. My boat had not been used in several years and the tank was full of KRUD, which cheerful plugged my nice new fuel filter.

My second use of it was a situation where the engine suddenly quit - no fuel pressure. This piece of info eliminated the ignition system and quickly steered me to the problem - the fuel shut-off valve was in the off position...

I never look at it otherwise I confess.

Peter

[tac]

Fuel Sytem Filters and Gauges

This, posted by Neil Dutton, contains USCG fuel requirements. Note the prohibition on plastic or glass for inboard gasoline systems. These are U.S., not Canadian, requirements:

http://www.moyermarine.com/forums/showthread.php?t=9280

ABYC Gasoline Fuel Systems. These are recommended standards:

https://ia800208.us.archive.org/10/i....H-24.1993.pdf

This thread, started by Neil Dutton, has an informative writeup about filter ratings. I think post #1 of this thread should be mandatory reading for all, even if it contains that smelly word, “diesel”. I would only add to this that physically small filters, like the one in post #1, will clog up mighty fast. They might be good for a small lawnmower engine, but not an A4:

http://www.moyermarine.com/forums/sh...d.php?t=4702)?

Your own thread post of 2016 has specific suggestions on secondary filters:

http://www.moyermarine.com/forums/sh...7877#post97877

If you are avoiding the Moyer secondary (“polishing“) filter because of high import costs, search out a Canadian auto parts store for the Hastings GF2 or GF10 or Baldwin BF833 filters.

As for a fuel pressure gauge:

http://www.moyermarine.com/forums/showthread.php?t=9369

[JOHN COOKSON]

There are various ways to install the fuel pressure gauge. I went with a 2" nipple off the carburetor -> a tee -> to a barb on the tee -> to the fuel polishing filter. The gauge twisted into the port on the tee that was not in line. All 3/8"* plumbing.

MrGasket gauges are popular. I went with a JEGS brand gauge because it has a glass face and stainless steel case. It is also liquid filled. Liquid filled gauges have advantages and disadvantages. You can google fuel pressure gauges, do a bit of research, and fine the one that is best for you.

TRUE GRIT

*Make that 1/8 plumbing.

[sastanley]

Greg, The key to make all of this work is to ditch the copper fuel lines you mentioned earlier, and replace with A-1 rated fuel hose..The fittings on carb & mechanical fuel pump are all 1/8" NPT, so you need some hose barbs with 1/8" NPT male on one end and the correct barb for fuel hose on the other (typically 1/4", but just depends on your local supplier unless you pick up supplies from Moyer.)

The Moyer panoramic shows a typical canister polishing filter install (with electric fuel pump)..the pressure gauge should be directly before the carb. As you can see, the soft fuel hose in that pic is also similar to how you can do mech pump to carb..

[GregH]

I am assuming that running the hose to the inline filter, then to the "T" with the gauge and then to the carb doesn't cause any problems with it just hanging down?

[sastanley]

Nah, I don't think so, Greg. On my engine, I have a Mr. Gasket brand $15 gauge, and it hangs with a 1/8" NPT tee between the filter and barb on the carb.
I suppose if you wanted to eliminate some clamps and fittings, you could attach a tee with male 1/8" threads on one side directly to the carb, female for the gauge, and the barb for the fuel hose on the 3rd opening.
However, that would make things more vulnerable I think. I have 90°'s on mine (Either a 90° barb, or an elbow, etc.) so they barbs lay vertical and don't stick out, similar to the Moyer pano pic.

[tac]

Fuel System Requirements

Details of gasoline fuel system installation are covered by the Coast Guard and ABYC, as mentioned in post #9. If you aren’t familiar with these, here are some excerpts, with comments in italics.

From the USCG Requirements of 2003

“FEDERAL LAW:
183.501 Applicability.
(a) This subpart applies to all boats that have gasoline engines, except outboard engines, for electrical generation, mechanical power,
or propulsion.”

“183.505 Definitions.
As used in this subpart:
Fuel system means the entire assembly of the fuel fill, vent, tank, and distribution components, including pumps, valves, strainers, carburetors and filters.”

While there is no mention of gauges here, the words “entire assembly” and “distribution components” imply that gauges, pipe tees, hose adapters, etc, are included in the fuel system.

“183.562 Metallic fuel lines.
(b) Each metallic fuel line must be attached to the boat’s structure within four inches of its connection to a flexible fuel line.”

It goes on to discuss allowable connections, clamps, hose types, etc.

“183.566 Fuel pumps: Placement.
Each fuel pump must be on the engine it serves or within 12 inches of the engine, unless it is a fuel pump used to transfer fuel between tanks.”

“Most engines are equipped by the engine manufacturer with a fuel pump as an installed engine component. For engines that are not so equipped, a remote fuel pump, usually electric, may be used. In order to keep the length of the pressurized portion of the fuel distribution line at a minimum, it is required that a remote fuel pump be installed within 12 inches of the engine. The 12 inches are measured directly to the engine, not along the fuel line.”

“183.570 Fuel filters and strainers: Installation.
Each fuel filter and strainer must be supported on the engine or boat structure independent from its fuel line connections, unless the fuel filter or strainer is inside a fuel tank.”

“Fuel filters and strainers may not use the attached fuel lines for their primary means of support. Many fuel filters and strainers have brackets designed to provide support. If brackets are not provided as part of the fuel filter or strainer, clips, straps or other means must be employed to support the fuel filter or strainer independent of its connected fuel lines.”

Although not stated, this requirement is to provide strain relief for the fuel lines due to the weight and vibration of attached components. A gauge and any attached tee and hose adapters may thus fall into this requirement, since they are implied in 183.505 above. Locating a mounting position for this filter and a gauge for easy access is NOT limited by the 12” rule of 183.566, since the fuel line from the pump (whether mounted on the engine or a nearby bulkhead) to the engine can be any length as long as the pump is within 12” of the nearest part of the engine. Hard mounting the secondary filter and gauge and its hardware is easily done with pipe clamps or hangers.

ABYC H-24 1993 Recommendations (my paper copy is 2005, but is similarly worded)

“24.9 FUEL FILTERS, STRAINERS AND WATER SEPARATORS
24.9.1 The unit shall incorporate means for independent mounting, designed to relieve strain from connected fuel lines.”

This can be read to mean anything connected to the fuel lines must be supported in order to provide strain relief. Strain relief is not mentioned in the USCG rules, but I think it is implied by their mounting requirements.

“24.14.6 Fuel filters shall be independently supported on the engine or boat structure.”

“24.14.7 Electrically operated fuel pump systems shall be connected to be energized only when the engine ignition switch is on and the engine is running. A momentary type override is acceptable for starting. Electric fuel pumps, if used, shall be independently supported and located within 12 inches (305mm) of the engine. The outlet pressure of electrically operated fuel pumps shall be rated or controlled to the maximum carburetor fuel inlet pressure specified by the engine manufacturer.”

I like this last sentence. It almost begs for a fuel gauge!

[GregH]

Conveniently (at this time but my knuckles may argue)) the icebox wall is within about 8" of the engine (see my account picture)