Fuel Filters

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viva

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I have a Yanmar 2GM which has a CAV primary filter. I don’t like the idea of not being able to see the sediment or water in the bottom of the filter as it doesn’t have a glass bowl, so I started to investigate swapping to a glass bowl, but then read a number of posts on this forum recommending Racor filters. So I proposed a swap to a Racor filter to the excellent and knowledgeable mechanic that does the serious stuff on my Yanmar. He suggested retaining the CAV filter but inserting a Fuel-Guard filter before the primary filter. Is this overkill ? Shouldn’t 2 filters be enough even with an increase in bio diesel related contamination? What is your opinion please?
 
viva said:
I have a Yanmar 2GM which has a CAV primary filter. I don’t like the idea of not being able to see the sediment or water in the bottom of the filter as it doesn’t have a glass bowl, so I started to investigate swapping to a glass bowl, but then read a number of posts on this forum recommending Racor filters. So I proposed a swap to a Racor filter to the excellent and knowledgeable mechanic that does the serious stuff on my Yanmar. He suggested retaining the CAV filter but inserting a Fuel-Guard filter before the primary filter. Is this overkill ? Shouldn’t 2 filters be enough even with an increase in bio diesel related contamination? What is your opinion please?
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I really like the glass bowl feature (actually acrylic but you know what I mean) on my Racor. If I can see sparkling clear diesel, which I can now after treating the fuel with Marine 16, I feel reassured. I don't know whether the Fuel-Guard thing has a glass bowl but if so then it sounds good. If it doesn't have the bowl then I can't really see the point.

Richard
 
viva said:
I have a Yanmar 2GM which has a CAV primary filter. I don’t like the idea of not being able to see the sediment or water in the bottom of the filter as it doesn’t have a glass bowl, so I started to investigate swapping to a glass bowl, but then read a number of posts on this forum recommending Racor filters. So I proposed a swap to a Racor filter to the excellent and knowledgeable mechanic that does the serious stuff on my Yanmar. He suggested retaining the CAV filter but inserting a Fuel-Guard filter before the primary filter. Is this overkill ? Shouldn’t 2 filters be enough even with an increase in bio diesel related contamination? What is your opinion please?
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Firstly, there's a lot of misunderstanding about CAV filters. The fuel in the bowl should already have been filtered, so you shouldn't see any sediment in it, although there may be water. If it makes you feel happier, fit a glass bowl to your CAV - it'll only cost a few quid. For what it's worth, I've never seen any water in the bowl of any of the CAV filters on my boats over the years, if you keep your tank fairly full there'll be minimal condensation so shouldn't be water in the tank. If you find it mentally challenging to change the CAV filter element (some people do), then changing it for a spin-on Racor-type filter will make the job easier, otherwise the CAV will be totally adequate.

Secondly, the Fuel-Guard filter is an over-hyped device, ridiculously expensive and I'd say it's certainly overkill for your engine installation.

Thirdly, it's a sensible idea to add fuel biocide every time you top up the tank, and to change the make of biocide from time to time.
 
Personally I think the glass bowl is overrated, I am changing to a spin on Delphi 496 filter this winter, twice the size of a 296 and with a proper drain at the bottom to inspect the fuel. The filters are cheap and widely available. Again see SSL.
 
RivalRedwing said:
Personally I think the glass bowl is overrated, I am changing to a spin on Delphi 496 filter this winter, twice the size of a 296 and with a proper drain at the bottom to inspect the fuel. The filters are cheap and widely available. Again see SSL.
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When changing filters do you have to pour fuel into this? I can't make my mind up about what to do in upgrading my fuel system. Ideally I want the simplest in terms of doing a quick change - unfortunately Yanmar's need bleeding (in this day and age!)
 
hi

yes you still have to get the air out via bleeding, that is driven by the engine / fuel pump design really. If you want to avoid it in emergencies then a twin switchable filter system is the way to go, easily made up from bits, ASAP did sell a diagram with all the part numbers.
 
dgadee said:
When changing filters do you have to pour fuel into this?
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All filters will need to be filled with fuel when fitted; the way I made this easy was to insert an outboard-style rubber bulb pump immediately after the tank. I fit the filter dry, then open the vent and give three or four squeezes of the pump until fuel comes out. Job done.

With the primary vent closed, if required this pump will also push fuel and air right through the second filter and the injection pump then back to the tank via the return line, bleeding most of the system much faster than fiddling with the hand lever on the engine. The only bit it doesn't fill with fuel is the injector lines, but so far on my engine those seem to look after themselves.

Pete
 
I have one of those water separators as first in line on mine & I'm glad I do as I was very surprised by the amount of water that built up in a very short space of time. It is a piece of cake to drain it off while the engine is running.
 
I've just changed the original CAV filter for a screw on filter from SSL in Scotland. It is a direct replacement for the cav filter head and changing the filter is a doddle - MUCH easier and quicker than the cav as you don't have to line everything up, get the rubber rings in position, and then find it still leaking! The new filter still has a drain tap for draining any water(but never found any), and filters cheaply available. If you go this route, make sure you get the correct type, either original UNF or later Metric threads. SSL are helpful. I am assuming you have an engine mounted filter as well?
 
Racor fiters have a pump on top or use the tab on the fuel lift pump, with the bleed crew open and tissue around it to catch the diesel. It's definitley worth having a clear bowl on the bottom of filters, in the Caribbean dirt and water in the diesel is endemic. In the UK it doesn't happen often but still worth having a clear bowl what we found occasionally was water.
 
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