Difference?

[James S]

If you can switch from one filter to the other then why do you need two vacuum gauges?

I'll be installing a single one that I'll tee into the engines supply line after all the primary filters and valves and before the secondary filter that came on the engine.

I'll mount the gauge in a location that I can see without opening any hatches.../may even be near my DC panel.

It will register what ever filter is being used.

As someone brought up....It would make sense to have another one down stream of the secondary/engine filter....I'll have to think about that?

[Chief Engineer]

That makes better sense...and you can get a bulkhead mount/surface mount vacuum gauge...be sure to use an oil filled gauge, other wise all you will have is a pulsating needle....ttthhhhaaaatttt yyyyoooouuuu cccaaannnn''''ttttt rrrreeeeaaaadddd!!!!!

(I like to keep things light!!!)

[Extemporaneous]

Originally Posted by James S

If you can switch from one filter to the other then why do you need two vacuum gauges?

How else would you know which of the two filters is the one that is plugged? Unless your filters are in parallel with only one in service at a time. Mine are in series and meant to both be online under normal circumstances.

Originally Posted by James S

I'll be installing a single one that I'll tee into the engines supply line after all the primary filters and valves and before the secondary filter that came on the engine.
I'll mount the gauge in a location that I can see without opening any hatches.../may even be near my DC panel.
It will register what ever filter is being used.

Many ways to skin a cat. With more thought perhaps I'll see your way as skinning it more efficiently/sensibly.
I do know that when running normally (clean filters) both of my vacuum gauges will/should (I think?) read close to the same. Someone straighten me out of this is wrong.
If the first filter in the series is plugging up, both vacuum gauges will read the same, however with high vacuum.
If the second filter in the series is the one plugging up, then that vacuum gauge will read more vacuum then the first vacuum gauge on the first filter.

If both vacuum gauges read the same with high vacuum, I will change the first filter in the series first and then take it from there.

Originally Posted by James S

As someone brought up....It would make sense to have another one down stream of the secondary/engine filter....I'll have to think about that?

I'll have to give that some thought also, but I think leaving this out will be one of my compromises knowing what I have done up stream already. What does come to mind right of the bat is that this might be a pressure gauge and not a vacuum gauge depending on whether it is before or after your lift pump. In my case it would definitely be after my polishing/backup fuel pump and so would be pressure in that case. I will be changing my stock engine filters as a maintenance item, but risk of them plugging should be minimal considering that my add-on filter system filters down to 2micron and the stock filter is 5 or 7micron.

Regards,
Extemp.

[Chief Engineer]

Putting a pressure gauge downstream of your lift pump is fine.

But all that will tell you is fuel pressure to injection pump.

With all due respect, don't complicate your engines with gauges unless you plan on logging the info on every watch....

Just remember things go wrong in threes....Dark night, windy coming into a reef enclosed anchorage and one of your gauges/hoses either sucks air or springs a leak....no en-gine............DOH!!!!!