Universal 5432/M40 fuel system question

Hello All,
If you have a Universal 5432/M40 I would like to know the sequence/path of the fuel to the engine. I know the late model M40 has an electric lift pump while the 5432 "should" not. That said, I know "some" M40's have a mechanical pump on the engine, just like my 5432.

The fuel line leaves the tank runs to a Racor FG200 filter, then a Mikuni mechanical fuel pump on the side of the engine just below/behind the injection pump, then to the primary engine mounted fuel filter and finally to the injection pump itself.

I'm still trying to figure out why the Racor develops an air bubble on my setup. I would like to know the location of the electric lift pump on the late model engines and also if they have the mechanical pump or not.

TIA, RT

The manual for our 1989 E38-200 said the engine was (I think...) an M-40, but on the engine itself the plate said 5432. Whatever it was, mounted on the bulkhead between the engine and the head, was the Racor (forward), then the electric fuel pump (aft). There was no mechanical lift pump on ours.

Fun & Games with the 5432 fuel system

I have modified Kismet's fuel system some. I have two Racor 500 series filters on separate pick-ups from the fuel tank with a switching valve between them. I mounted a small electric automotive type fuel pump after the filters in the line that runs to the 5432's mechanical fuel pump. The mechanical pump feeds the injection pump directly. I removed the factory spin-on fuel filter. I run 2 micron filters in the Racors.

This set-up allows me to switch filters easily even with the engine running. The electric fuel pump can be switched off at the engine panel but I leave it on all the time. It is also useful when bleeding air out of the system. You can run the electric pump until all the air is out of the system without having to turn over the engine.

Actually, the stock mechanical fuel pump doesn't have much to do since the electric pump provides plenty of fuel pressure. The factory spin-on filter was about a 10 micron affair and it was in a place that made it difficult to change. Since it was in the line after the 2 micron Racor, there was nothing for it to do anyway.

I think sooner or later I'll add pressure guages to the Racors so I can anticipate switching over the filters instead of waiting for the fuel pump to start rapping.

The Racors are mounted side by side in the starboard lazarette on the forward bulkhead and outside of the engine compartment. I also replaced all of the fuel lines with the marine grade rubber type when I did the filter job a year or so ago.

I've now run this system for 400 hours plus with no issues.

Thanks for the replies!

Ron, your setup is similar to what I am going to do. I don't have two pickups, and don't really need two filters, though I understand why you have them, cruising it make a lot of sense.

I was thinking: fuel tank-facet electric pump-Racor 500 @10microns-mechanical pump-factory spin on filter-injection pump.

Wiring the Facet through an oil pressure switch with an override to prime.

My only concern with your setup would be one of the pumps having an issue and possibly dumping debris into the IP? Since, AFAIK the Racor 500's will run at up to 15psi pressure I would rather push fuel through them than pull it. Given the stock spin on filter is only 10microns leaving it there won't really hurt anything, it will likely never need changing.

I like your filter mounting location but my battery charger lives there currently. I am changing chargers so that space will be available shortly.

Thanks, RT

Per Westerbeke, the engine mounted secondary filter is 25 microns.

http://www.ericsonyachts.org/infoexchange/showthread.php?t=7540

RT - Sounds like a leak in the Racor or in the feed line to it.

FWIW, Racor recommends installing their filters on the suction side of the pump.

http://www.a-filter.se/files/racor_products.pdf Page 3.

Does your Racor have a plastic bleeder screw? Mine had a plastic hex head with a screwdriver slot and the head cracked off, leaving most of the plug in the body of the valve. The replacement is brass.

I think my electric pump is between the Racor and the on-engine filter.

try checking the pick-up tube

I've seen air in the racor bowl on 2 occasions over the years. My experience:

First time the engine experienced no issues, replacing the filter, o rings and tightening everything up did the trick. I replace the filter annually and never saw air again - until....

Second time my engine stalled and would not restart, very little fuel in bowl. Turned out the fuel pick up tube had a crack at the very top by the fitting, and the tube "seperated" from the fitting (no fuel). I imagine a smaller crack or issue could introduce a "little" air into the system. Replaced the tube and no problems since. I understand the these tubes are known to fail.

RT my set is identical to yours. Tank to filter to electric lift pump to spin on engine filter. A few thoughts:

1. I dont recognize the Racor FG200, did you mean FG500? Is this a centrifugal filter or spin on cartridge type? The 500's are the way to go IMHO.

2. If you get bad fuel or crud in your tank wont it affect the lift pump if you have it between the filter and the tank? Part of the filter's job is to protect the pump. Not sure what you are worried about coming from the pump to the engine and thats where the OEM spin on filter would do its thing anyway.

3. Obviously youve thought of this but I'll say it anyway. Check all of your hose connections and the seals on the filter assy...

4. A clogged pick up in the tank could be causing the pump to suck in air elsewhere too ( path of least resistance) but you would probably find that in (3). Pump would have to work pretty hard for this.

Follow this thread to find out how this question was resolved.....

http://www.ericsonyachts.org/infoexchange/showthread.php?t=7660

RT