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TomZ 03-28-2021 01:17 PM

Electric fuel pumps - 311/TRS
I may have asked about this in my engine but can't quite remember so I thought I might get better traction here.

My 509s have no fuel pump provisions so I picked up some 140 GPH Holley pumps to run everything. I'm trying to figure out where to mount them.

I'm thinking they could go on the outboard stringers as low as possible and then force-feed the fuel /water separator/filter. I would need to wire all of this with a relay for the ignition/oil pressure switch (not too hard). One of my concerns is the tank depth relative to the pumps. I'll try to mount the pumps as low as possible on the stringers. I don't think there's enough room inboard stringer.

Anyone done similar with a 311 or 357?


TomZ 03-28-2021 01:26 PM

I saw that some here on OSO had the pumps mounted on the engines directly attached to the water separator housing. I'm thinking that would create an issue with pulling fuel too far uphill to be safe for the pumps and engine.

Really wishing I had the ability to run mechanical pumps.

TomR 03-28-2021 05:48 PM

Hi Tom,

I run Aeromotive electric pumps in my current boat that are mounted on the stringers in line with the outside of each engine that are just about level to the tops of the tanks. I do run an in line hi-flo filter before the pumps and then a filter water separator after.

Two boats ago, I had a 28 Scarab (single engine 540ci) with the electric pump mounted on the bulkhead about level with the top of the tank before the filter separator.

I would try to keep the pumps as low and close to the tank as possible and try to find a good flowing filter to mount before the pumps if you can.

TomZ 03-28-2021 08:38 PM

Thanks Tom.

I wish I could use the bulkhead but itís right up against the tank so no go there.

I need to get in the boat to see what the best course will be. Always easier with the engines out so bows the time.

Filter before pump... Iíve had negative results with filters before Holley pumps. Iím guessing Iíd need a really course filter prior to the pump to keep from getting it bunged up.

TomR 03-29-2021 06:12 AM

If you look on the intake side of the fuel pump there may well be a screen.

Keith 03-29-2021 07:15 AM

I would highly recommend you have a conversation with Holley before you do anything else. According to someone at Holley when I was researching this issue, I was told their pumps are designed more to "push" fuel, not pull fuel from the tank. They recommended installing the pump below the fuel level of the tank. That would have involved moving my pumps into a position too low in the bilge for my comfort.

The second issue then becomes where to place the water/fuel separator filter, either before the pump, or after the pump. If the design of the pump is geared towards pushing fuel, then you'd want the water separator filter in between the pump and the engine. The third and final is issue is "ethanol" which is the only fuel available to me. You'll have to decide if the advertised "methanol" compatibility includes "ethanol". I've recently seen some seawater pumps that can use a mechanical fuel pump. Perhaps that's a solution?

In my case, after I finally blew up an engine, I bought Dart 509's with mechanical pumps.

TomZ 03-29-2021 07:30 AM


I looked into that too, and so long as the pump is kept at the minimum fuel level, it should work. The pump will draw uphill and self-prime in the short distance to create the siphon effect thus gravity feeding the pump.

Unfortunately, the packaging of the gen VI 502 does not allow the use of the seawater pump driven fuel pump. I would need to convert the entire accessory drive and brackets to do this. It's not in the cards right now.

Keith 03-29-2021 07:53 AM

Tom, I truly feel your pain. I went through this over a period of 2 or 3 seasons when the pumps repeatedly failed at speed. It was also during our transition to ethanol, which created other issues. I can't say it directly caused the engine failure, but it's still in the back of my mind.

Knowing what I know now, I would have paid quite a bit of money converting to mechanical.

Mr Maine 03-29-2021 09:09 AM

Ive done it with no issue. Pump mounted low and close to the tank. Need to remove the anti-siphon check valve at tank pickup.

TomZ 03-29-2021 01:38 PM

Originally Posted by Mr Maine (Post 4783508)
Ive done it with no issue. Pump mounted low and close to the tank. Need to remove the anti-siphon check valve at tank pickup.

Where did you end up mounting yours? Any pics you'd want to share? I know our bilges are similar.

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