Diesel fuel filter system

A benefit of having an add'l vac gauge before the filters is if the vac gauge after the filters is showing an alert the 1st one will show if the issue is possible tank vent , pickup or outlet issue instead of filter restriction.

And Smitty , while I agree there is certainly a tendency and need to rely on mechanical gauges when confidence in dash gauges is iffy, mechanical gauges can definitely read erroneously too. A long-time excellent marine mechanic was checking oil pressure on my old Crusaders because one of the dash OP gauges was reading low. It turned out both the old dash gauge and the mechanic's mechanical gauge were off, his by 10 psi. He had a second mechanical OP gauge that read correctly on both engines. Both mechanical test gauges were of high-quality expensive professional-duty type.

I prefer the convenience of dash gauges for normal use , but have all the backup test gauges for those "special" times. Love the idea of the digital dash display of vac pressure from multiple senders. I just need more dash real estate.
 
"A benefit of having an add'l vac gauge before the filters is if the vac gauge after the filters is showing an alert the 1st one will show if the issue is possible tank vent , pickup or outlet issue instead of filter restriction"

Hello Sandy - I do not know how your vac gages are set up exactly so you may see different results than I do. My experience on this boat as well as my past boats is that any vac gage will show a tank vent issue immediately as it is occurring, and then the easiest way to see if it is the vent is to 'open' the fuel tank parallel valve and see if it drops. Another very quick method that was used by a number of the members on another board I post on is to just temporarily open the tanks vent and see if the reading(s) drop. In any and all of these cases the fuel vac readings become a key element in trying to chase down engine problems when you have them. Often we see posts where people say things like "it cant be fuel" , " I just changed the filters" or "they look good from the bowl" only to learn later that it was something in the fuel system.
Trying to solve engine issues can be hard enough with the best data but without measurable data you have some issues that just become a guess. I find the vac gages to be similar to pyro and boost gages in that they isolate issues much earlier and much more clearly then not having them.
Hope this helps
 
Thanks, Smitty. I agree with all you said. But not all boat have parallel tank valves though mine does.
But I have gassers and as such the conventional vac gauges ( at least most all of them including Racors) are not certified for use with gasoline fuel, only diesel, on marine engines, so I can't legally and don't have them permanently installed. But the digital vac display with remote sensors would USCG-legally and safely allow this to aid more rapid isolation of potential issues for me as you wisely suggest.
 
Sure will - its larger than the ones I use which is nice for reading the needle and comes already glycerin filled where I had to add the glycerin myself. I could picture you adding a "T" instead of the "L" on your filter out side and then a snubber and then this gage.
If you like sealant on fittings please do not use Teflon tape rather use a sealant rated for the diesel fuel such as rector seal, permatex #2 or anything similar.

Hope this helps
 
The gauge that CurrentSea linked doesn't have a tell-tale needle to show max reading. But is that a big deal? A Racor t-handle vacuum gauge does, on the other hand.

So is that "max reading" tell-tale needed? If the fuel system's vacuum reduces post-operation, I guess it would matter. Otherwise, you'd need to look while underway, which may or may not be possible for some.

Anyway, just wondering about that tell-tale. Thanks for your thoughts.

V/R
Bill
 
"Anyway, just wondering about that tell-tale. Thanks for your thoughts."

Tell tales are fine for those who have an application that needs them - mine are easy to read without needing to get in the engine room and I have seen others use cameras for the view. In some instances with friends boats we have 'extended' the vacuum gage "T" install with a length of fuel hose allowing the gage to be positioned where it is easier to read, caution to remember that there the hose is a potential source of fuel wherever it is routed. Most of these engines pump more than twice what is burned at cruising speeds and a multiple of that at lower speeds so the vac readings will often show filter issues at most any speeds - but it is worth a live view to test it out for your own application.
If you use tell tales the glycerin and snubbers become more important as you want to know the real reading and not a single spike caused by the natural cycling of the pump and lines - or a very temporary condition that can exhaust as start-up and shutdown on some engines.
The first time I installed one of these I did not use glycine or snubbers and the needle 'bounced' around covering a span of at least 4-5" or Hg at each cycle - Looked like the gage was alive.
Not good for readings or for getting any life out of the gage.
I am sure that glycerin alone would work , or snubbers alone would work, but since I have used them both I have had no issues with these gages over 8-10 season of use.

Hope this helps
 
The old copper was 1/2", so I replaced it with 1/2" hose. The filter head I got is 3/8". Is it a mistake to down size at the filter head? Further towards the motor, fittings are 3/8". The racor has 3/8 fittings as well. Is this normal?

Billy K.
 
quote:
Originally posted by BillyK

The old copper was 1/2", so I replaced it with 1/2" hose. The filter head I got is 3/8". Is it a mistake to down size at the filter head? Further towards the motor, fittings are 3/8". The racor has 3/8 fittings as well. Is this normal?

Billy K.

Click to expand...


Reducing to 3/8" should not cause any problems.

What kind of hose and fittings are you using?

the cheap black fuel line with hose barb fittings that need hose clamps? Or the high quality blue renforced hose with the hose barbs that have flare fittings on them that need no hose clamps?
 
Thanks for the reply.

I am using A1 Lawrence Marine non clamped slip on hose. It's not blue but is reinforced

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Billy K.
 
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