Electric Fuel Pump pressure

[Sam]

I have had my 1966 Morgan 34 w/early model A4 for about 40 yrs' Great freshwater Lake Michigan boat with still the original well maintained A4 running fine. I have gone through 3 electrical fuel pumps in that time and about to install the 4th. My setup is tank - see through glass filter - nearby5/7 psi pump - carb. The filter is near the bottom of the tank side, pump a little lower on nearby bulkhead, carb a foot lower.

My question is: I keep reading 4psi or lower is the preferred pressure for a new pump. Most diagrams I see show the filter between the carb and the pump vs what I have always had with the filter between the tank and the pump. I am "sucking" gas through the filter vs the standard "pushing " gas through the filter. Does the filter placement effect required psi. Admittedly when the pumps and filter filements are new I get a little gas leak/smell by the carb and it tends to go away after some use and I use the exhaust fan somewhat periodically while motoring [always prior to starting]. If I put a new 4psi pump on with my current set up am I going to get adequate gas to the carb???

[Al Schober]

Sam,
First, welcome to the forum. I hope we can help.
5-7 psi is a lot more than you need. I have an electric fuel pump and a small pressure gauge on the inlet of the carb, and have just under 3 psi. These engines will run fine with NO fuel pump, just gravity feed from a tank slightly above engine level.
Next, see-thru filters have no place on an inboard gasoline engine. They're OK for diesel or a gas outboard. My system uses two filters. The fuel line comes from the tank and goes (thru a ball valve) to a small Racor with a metal bowl. Next is the electric fuel pump. There's a second in-line metal filter going to the carb.
These filters require regular replacement. Ethanol fuels pick up water which will corrode the metal parts of the filters, and the corrosion products will end up in the carb.

[ndutton]

Welcome to the forum Sam. What brand and style pump are you using? If the failures you have experienced over the years have been Facet cylindrical pumps, please know that there was an era of known defective Facets. Check out this treatment:
http://www.moyermarine.com/facet.htm

By the way, the proper fuel system hierarchy according to Parker-Hannifin/Racor is tank→filter→pump→carburetor. An optional polishing filter if desired goes immediately ahead of the carburetor.

Further, have you upgraded your fuel hoses to tolerate ethanol blended fuel? A boat as old as yours would certainly need it.

[lat 64]

Originally Posted by Sam

.... I am "sucking" gas through the filter vs the standard "pushing " gas through the filter. ...

The standard, IMHO should be the regulation location which is 12" or less from carburator inlet.
The reason, I believe, is to have any (eventual) leaks in the line be an air leak into the line and not a fuel leak out spraying into the engine room.

You sound like a thorough person so at the risk of belaboring the obvious, I'll add two more considerations:

• an anti-siphon valve at the outlet of the fuel tank.
• an oil pressure safety switch(OPSS)

If you don't have either of these, please consider them too.


Welcome to the forum,

Russ

[tac]

See http://www.moyermarine.com/forums/sh...ad.php?t=10459 for Coast Guard requirements and ABYC recommendations. The Coast Guard reference mentioned there also requires an anti-syphon device and the grounding of various metal fittings. It also covers allowed fuel filter types, pump location, required fuel fill/vent/distribution hose types, et al