Vacuum Gauge Proves Its Value

[Administrator]

Last weekend, we took a trip down the Bay which amounted to about 80 miles under power. On the return, I happened to notice that the reading on the fuel vacuum gauge had crept up from the 3-5 range to around 10 (the high end of the "Yellow" range on the Racor gauge), though the engine seemed to be running ok. Time to change the filter, I thought, even thought it was new this spring.

Changed the filter a couple days ago. Now the gauge reads 12 (in the "Red" area). Hmm. Swapped the gauge with the one on the polishing system. Same reading.

Eventually, my favorite marine technician came by, disassembled the manual fuel shut-off, and dug out three BB-sized spheres of silicone from the valve. Put everything back together. Vacuum reading back to 3.

So where did the the three BB's come from? I just had the sending unit out within the last month. That was bedded with silicone. Maybe the silicone was applied across a screw hole and got pushed down through the hole and into the fuel when the screw was inserted?

Interestingly, two of the three spherical blobs were clear and one was white, suggesting two different contamination events.

It surely was nice to find the smoking gun. Absent that gauge, I would have eventually either lost the engine to fuel starvation while underway or simply burned out the fuel pump.

Love that gauge!

Bill

[joe_db]

Do you have one or two gauges?
I sometimes stick one on the input side of the racor to see where the clog is and always have one on the output side.

[Mo]

Hi Bill,

Every time I used silicone around gasoline it literally broke down, regardless if it had set-up or not. I always ended up having to take it all apart, prep the surfaces again then put on Seal All. It works well and lasts.

I've used "Seal-all" on a sending unit in my Izuzu Trooper years ago and it lasted 6 years that I had it. http://eclecticproducts.com/sealall.htm

That said, I run an electric fuel pump as well and should look at putting a guage on it. When it's all running well we put our resources elsewhere. My next project is to refinish my teak floors and put a shine on the top-sides.

Have a good weekend guys!

[Administrator]

Do you have one or two gauges?
I sometimes stick one on the input side of the racor to see where the clog is and always have one on the output side.

Hi, Joe:

I have two gauges and two systems. One is the engine system. The second is a stand-alone fuel polishing system. Each gauge is mounted downstream of its own Racor.

Bill

[joe_db]

If you have one on the upstream side too you can detect clogged pickup tubes and vents. The racors have 2 input ports, so it is an easy hookup. I had my fill hose dissolvle from the inside out and drop rubber pieces in the tank that clogged the pickup screen
Then it ate all the way through and when I filled the tank I filled the bilgle too

Hi, Joe:

I have two gauges and two systems. One is the engine system. The second is a stand-alone fuel polishing system. Each gauge is mounted downstream of its own Racor.

Bill