Parker (Racor) and Gulf Coast Filtration make dual filter setups that you can switch back and forth on the fly, they seem to use the turbine series filters and are very pricey.

There are also a lot of "roll your own" setups, it's all just a matter of installing enough lines and valves to be able to change filters on the fly. Finding a home for all the plumbing can be challenging. I was going to do this on our 28, a guy on the Catalina 28 forum put one into his boat using another of the same Racor units that the boats came with, but it is simpler and cheaper (IMHO) to just pull the tank every 5 years and clean it. And use a Baha filter when fueling from suspect sources.

I changed my own fuel filters for the first time on this boat and I found it went really well. I used a plastic ice cream container under the racor and didn't spill anything from it. I found that a 500 ML yogurt container fits perfectly over the spin on filter at the engine allowing you to undo the filter with the container already in place, also didn't spill a drop. Bleeding was really simple, I just jumped power from the starting battery to the fuel pump and I watched it suck fuel into the racor until it was full then shut the pump down. Then with the yogurt container in place under the spin on I started the pump again and waited until I had good flow out of the vent on top of the spin on unit and then closed it and shut the pump down. Then I powered up the pump again and opened the bleed screw on the return line until I got fuel and then shut that bleed screw and then shut down the pump. That was it. Hardly any smell of diesel at all, none spilled onto the boat anywhere and what there was on the engine I was able to wipe up easily. The engine fired first crank and never missed a beat since.

Wouldn't want to do that in rough weather though, and as we all know, that's when you'll need to change a filter.

Parker also makes a fairly inexpensive and low amp draw fuel polishing rig for small scale use like on our boats, I saw it for less than $500 a while back.

One thing I've always wondered, the Racor is a 2 mic filter, despite many experts saying the first filter should be a 30 mic unit they usually are 2 mic. The filter in the fuel pump is 74 mic and from what I can find out the spin on is 30 mic. Question is, how can the filter in the fuel pump and the one on the engine ever get dirty if the Racor is picking up finer particles than either of them can even see? Perhaps someone here knows? 'Cause by my feeble logic, one should never need to change anything but the Racor. But I dutifully change everything every year.

Your logic is exactly correct, you want to go progressively finer in the filtration stages.

As a general guideline, Nigel Calder suggests 10 to 30 for the primary and 7 to 12 for the secondary (although he says they can be as fine as 2). The primary filter is there is trap the big bits so the secondary doesn't plug up too quickly.

I further suspect that fuel pump filter exists only to protect the pump and should not be considered an active element in the serious filtration process.

The manufacturer's spec for the secondary filter would be the starting point, it is their engine's injection system that must be protected.

I looked up fuel filters for the M25 on our site, and checked a couple of the manufacturers' spec's. If the cross-reference table is correct (and I am confident that it is); then this is what Universal/Kubota intends for this engine.

From these, I found that 10 microns is the specification for the secondary (engine) filter. Therefore, 30 microns would make sense for the primary.

Bud wrote: [I]Question is, how can the filter in the fuel pump and the one on the engine ever get dirty if the Racor is picking up finer particles than either of them can even see? Perhaps someone here knows? 'Cause by my feeble logic, one should never need to change anything but the Racor.[/I]

The logic works backwards, too! :) I've used 2 micron Racors, re-plumbed so the fuel pump is AFTER the Racor, and only change my engine mounted filter once every two or three years. The pump filter should never have to changed (or even cleaned, but it's always good to check it) because it should be [U]after[/U] the primary filter.

The Racor is simply easier to get to on our boats. Easier to change, too, because the access to the engine mounted secondary on our boats is not as easy as yours.

Logic? Not feeble at all, Bud, it's actually very smart.

I found the pictures from the 28 website of the fellow's boat who installed the dual filter system. There is a lot less room in the 28 for this than there is in the 36, might be able to do it on one side of that area instead of on both sides.

In the photo, the fuel pump and filter at the bottom are in the stock location. The filter opposite those is the one he added. The fuel tank on the 28 is in the aft starboard side. So the stock flow was from tank to the fuel pump, but he changed it so the flow goes to the T block at the back and from there to both filters. Then it exits the filters and goes to a switch which lets him select either filter. Then to the fuel pump and onward to the filter at the engine.

Not a terribly complicated system and it works. Probably the hardest thing to do is find the plumbing pieces. Just noticed I think the filter is an R24T which is a 10 mic, first time I've seen anything but an R24S on there.

I just found a 220R filter unit brand new on eBay for 86 bucks! That's less than the sight bowl alone costs up here to replace so I bought it and am going to install it as 2nd filter. But instead of the way the one above was done with a T block before the filters I think I am going to use two 3-way valves, one on either side of the filters. That way I can totally isolate one filter and can change it on the fly while the engine is still running. Because Murphy's Law lives on boats, mostly.

Ben,
I'm confused by your comment
"I'd like to be able to change both fuel filters without having to bleed the fuel line and injectors, which was quite messy/smelly when I did it for the first time last year."
By the year of your boat, you have the Universal M25 engine. The M25 has the SIMPLEST bleeding procedure of any diesel I have every seen. You simply have to open the bleed thumb screw, turn on the key (which energizes the lift pump), and wait until the lift pump bleeds the system for you. The rapid tapping sound of the lift pump will change to a slower tapping sound when fuel, instead of air, is in the system. You should not have to touch the injectors unless you remove them. I'm not saying you should not change to a turbine style filter (such as Racor), as the Dahl filter elements are not easy to find, and changing the filter element can always be messy and smelly, but at least the bleeding procedure is super-easy. Hope this helps.

I agree 100% with what Tom said about the U25.

I have the U35 in my current boat and, while I never tried it on my 25 this is what I do and it works like a charm.

1st, fill the new filters with fuel before putting them on (both primary & secondary). Leave the secondary cracked just a bit and try to start it. It will turn but not catch, but after about 5 seconds it will cough like it wants to start. Tighten the secondary at that point and it starts every time with no bleeding at either the secondary or at the injector block (if that's the correct name for that part).

Chuck Parker

Yup, try this, even simpler bleed than posts noted below: [url]http://c34.org/bbs/index.php/topic,5558.0.html[/url]

All of us, and I'm sure it really is ALL of us, have had first timers trepidation about bleeding, having read horror stories for years about diesel engines.

An M25 and M25XP couldn't be simpler.

Oh, yes, something could be: an M35 - self bleeding.

And, there needs to be NO fuel spill, mess or anything other than changing the filters, but that has nothing to do with bleeding, it's all in your technique of un-screwing cans from a holder. Once they invented the pop-top can, I forgot how to un-screw stuff...:)

Dented new filter [url]http://c34.org/bbs/index.php/topic,2915.0.html[/url]

How to Bleed: [url]http://c34.org/bbs/index.php/topic,2884.0.html[/url]

Ken's become our self-styled "bleed" expert, and has made it soooo simple, even I can do it!

Looking at my O&M manual as well as comments on line there seems to be some differing opinions on should a RACOR fuel filter/water separator be on the suction side of the lift pump or the discharge.  I have a 1983 C36 MK1 with the M25 engine.  Any help would be appreciated.  I have had the filter on the suction side for several years but when I went to change the filter the fuel pump does not seem to be pulling through to fill the filter back up.  Did I put her in backwards?  Thanks Griff