KAMD43P maximum fuel restriction?

[Falling Star]

I have fitted a RK11 1676E Tell-Tale Parker Racor gauge to the primary filter. The Racor spec. suggests that the filter should be changed at at least 2inHg before the fuel system's maximum allowable restriction.

Can anyone advise me what that figure is please? I can't see it on any of my Volvo information.

 

[Portofino]

Depends on the instal , the actual value VP quote ( if there is one ? ) for a stand alone is variable being dependant on the fuel line lengh and Dia
Ball park 8 inches Hg ,but thay may run fine up to 11-12 inHg .
http://www.sbmar.com/articles/understanding-fuel-line-sizes-vs-fuel-supply-restriction/

What problem are trying to tackle fitting vacuum guages to the racors ?

 

[Falling Star]

OK thanks. I was guessing around 10inHg from the markings on the gauge so that kind of confirms it.

No specific problem. Ideally I would fit an on board polishing system but it's not practical on this boat due to lack of space. I'm thinking that this gauge can maybe give an indication of trouble before it happens.

 

[Portofino]

Yes it will if "trouble " blockages occur slowly over time ,say if you do commercial hrs ,and check them routinely.

How ever if the rate of blockage is high ,say a piece of crud breaks away in the tank ,while you are fighting at the helm in a F6-8 ?on the bow ,then when the engines stop the guage should be well in the red .
If it,s not in the red then at least you know it's not your filters and you can look elsewhere .

Dedicated Fuel polishing ,is that just a marine engineer s merchant income stream ?
Your engines typically are returning 1GPM ,that's 60 Gallons /hour .
So on a long run @ normal rpm ,you can calculate knowing the tank contents how many times it's passed through your racors and 2nd engine filters .
Assume racors are 10 or 20 microns and 2nd on the engines 2 microns ? .

 

[Falling Star]

Single engine with one Racor 500, fitted with a 20 micron. Standard Volvo secondary filter on the engine.

It does however have two tanks. I normally run the tanks alternately as they each have supply/return lines with individual shut-off valves.