Understanding Racor Indicator Gauge

[O C Diver]

Wouldn't it be the vacuum between the check valve ball in the racor and the injection pump - a big part of the system, minus back to the tank?

Probably a better way to address this is that the cause of abnormal vacuum that the gauge is registering, is from the fuel tank(s) to after the Racor filter element. Somewhere between those two points is where a restriction is developing.

Ted

 

[Steve DAntonio]

It measures vacuum induced anywhere between the primary filter and the pick up in the tank, so a great troubleshooting tool in that respect.

I would only use a gauge with a drag needle, so you don't have to look at it while under load.

Article on fuel vacuum gauges and their use here https://stevedmarineconsulting.com/the-invaluable-vacuum-gauge-editorial-my-kingdom-for-a-set-screw/

 

[Comodave]

Racor also sells a different gauge that has the T handle built into it so you don’t need a tool to change the element. If you are going to buy a new one that is the one to get. $84 at the racorstore.com. It has the drag needle so you can see what the highest vacuum was after you shut the engine down.


Racor RK 19671 RK19671 T-Handle Vac Gauge For Current Turbine Models

 

[Steve DAntonio]

I prefer the Dent gauge, all the features of the Racor plus a more usable scale.

 

[rgano]

Ok, I'll bite. What's a Dent gauge?

 

[Comodave]

I prefer the Dent gauge, all the features of the Racor plus a more usable scale.

It doesn’t have the T handle which is a very nice feature and their web site has it listed for $145 if I am looking at the correct one.

 

[C lectric]

We purchased the newer T Handle Gages RK19671 for our Racor Series 500 only to discover that they are not useable with our low flow Ford Lehmans that sip fuel at 3 GPH. I have 3 of them for sale, brand new.

To late I am sure but:


I disagree.
Low flow or no low flow the vacuum guage will work. They do not care about the rate of fuel useage. They react to vacuum buildup.
Whoever told you that is wrong. Vacuum is vacuum and as the filter clogs the restriction to fuel passage will build up and with a telltale needle it will give you advanced warning instead of a slowdown or a shutdown.

If you still have them install them. If lucky they will have nothing to tell you but that does NOT mean they won't work.

 

[catalinajack]

To late I am sure but:





I disagree.

Low flow or no low flow the vacuum guage will work. They do not care about the rate of fuel useage. They react to vacuum buildup.

Whoever told you that is wrong. Vacuum is vacuum and as the filter clogs the restriction to fuel passage will build up and with a telltale needle it will give you advanced warning instead of a slowdown or a shutdown.



If you still have them install them. If lucky they will have nothing to tell you but that does NOT mean they won't work.

Another option. Available on sbmar.com.

 

[C lectric]

Another option. Available on sbmar.com.View attachment 127911View attachment 127912

Yes, I have those.

 

[Steve DAntonio]

Ok, I'll bite. What's a Dent gauge?

Dent Gauge https://dentmarine.com/

I understand the T handle install is convenient but I'm not a fan, I detail why here https://stevedmarineconsulting.com/the-invaluable-vacuum-gauge-editorial-my-kingdom-for-a-set-screw/

I prefer a permanent mount in the inlet plumbing at the primary filter. However, the T handle is certainly better than nothing.

More on primary filters here https://stevedmarineconsulting.com/...bolt-a-cigarette-lighter-and-distracted-work/