Primary Fuel Filter Changing

[Kelkara]

I have never in my life taken a wrench to an engine before ... but yesterday with the help of my engine's user manual and Nigel Calder's book I managed to perform a full service on my diesel . Even if I did have to remove both the alternator and the kitchen sink to access the heat exchanger.

However, the engine manual doesn't include the primary fuel filters, and NC didn't seem to be much help either, nor did google. So I have a couple of questions, if anyone can help...

1) I presume that I should change these filters at the same time as the secondary filter attached to the engine? Is this a good schedule for maintenance?

2) It's not clear to me how I go about changing these filters. If I just start randomly unscrewing things to see what comes loose I'm afraid I will either do something I shouldn't, or spill all that diesel into my bilge.

3) When it came time to bleed the engine, the manual just said "bleed the primary fuel filter as per manufacturers instructions". But I don't have any instructions, how do I bleed it? I just ignored them and bled the rest of the system as per the engine manual ... have I introduced a problem that will come back to bite me later?

After all my efforts, the engine still runs but I still have a lot to learn about keeping it that way.

[barnakiel]

I change them at the same interval as the one in the block.

The way I do it is a cut a PET transparent water bottle round the top and slide this vessel over the filter. Now I cut off the fuel. Now I undo the top bolt and the excess fuel and the old filter and some parts end up in this PET vessel (mind the re-usable parts - do NOT toss these away).

I chuck out old diesel and the old filter. I clean the re-usable parts, the glass bowl, the alloy plate, etc. I make sure the drain (often a plastic screw that is quite delicate) works fine. I place a new filter, gaskets, put all the stuff together.

Repeat with the twin one now.

When done, I open the bleeding hole ON THE MAIN FILTER THAT SITS ON THE BLOCK and now with the manual lift pump I pump till the primary filters are full and no bubbles come from the main filter bleeding hole.

In fact last two times I actually pre-filled these filters with fresh diesel as manual pumping took time and I am getting stiff in the small space of our 'engine room'.

So, easypeasy. One at a time, catch all the parts and remember to shut off the tank before the job then back on when done.

important notice: DO NOT overtighten the fitting bolt.

Cheers,
b.

[Stu Jackson]

If you have an electric fuel pump it is much easier.

For M25 series Universal/Kubotas:

Bleeding 101 Bleeding M25 Series Engines 101- A Summary of Links for You

You would help us to help you if you had told us what engine.

[Jim Cate]

You would help us to help you if you had told us what engine.

Actually Stu, he showed us the filters, which are not really associated with the specific engine model. Barney then gave quite concise directions on the replacement of the CVA filter elements. I don't think it matters what engine was connected to those filters!

Jim

[Kelkara]

Thanks! I think Barnakiel has nailed it. The description makes perfect sense ... now I'm off to buy a bottle of pop - that sounds like an excellent trick.

[Delancey]

Yes, fill the new filters full of clean fuel before you screw them on.

[Lepke]

If you put a vacuum gauge between the primaries and the lift pump, the gauge will show when the filters are getting dirty.

[Wotname]

FWIW, these appear to be CAV style filters; if so, ensure that you put the square edged ring seal on the top and the O ring seal on the bottom.

Here is a recent thread with some more detail
http://www.cruisersforum.com/forums/...em-184659.html

[dw1979]

I was at Trawler Fest in Bremerton this past Friday. There was a presentation by the Northern Lights generator people. They cautioned agains pefilling the filters as that that fuel could have particles larger then what you are trying to filter. Infection pumps and nozzles don't take kindly to the larger particles. They recommend to just take your time and use the mechanical pump (or electric).
I'll admit to doing a bit of back filling myself in the past but will not it the future. If the mechanical pump does not seem to be doing much good just rotate the engine a bit to get it off of the cam that operates it.

[Gary Mc]

I never could get the mechanical fuel pump to do anything on my Yanmar 2GM.
I installed an outboard motor fuel squeeze bulb in the line just where it comes out of the tank. It works great, after changing filters I just open the vent on the little filter on the engine and squeeze the bulb a few times.
When diesel sprays out (I hold paper towel over it) I am done.

Works great every time.

[sailormed]

You can fill the filters with clean (or dirty) fuel. Just make sure that you obstruct the central hole (threaded). This is where the filtered fuel comes out and continues to the secondary filter. Only pour the fuel in the outside holes, that way the fuel will be filtered and there is no particle size potential problem. After all the cartridge is there for filtering fuel, so just use the correct ho les for pouring and the cartridge will do its job.

[KP44]

Originally Posted by Kelkara

Thanks! I think Barnakiel has nailed it. The description makes perfect sense ... now I'm off to buy a bottle of pop - that sounds like an excellent trick.

I use whatever bucket or bottle I can fit under the filter unit. Works great.

I also installed a small electric fuel pump after the filter. To bleed the new filter I use the valve to return fuel to the fuel tank and just run the electric fuel pump for a couple minutes.

[redbeard1]

Hello,

We just did this on our volvo penta 2003. Our set up is fuel tank > primary fuel filter > electric fuel pump > mechanical fuel pump > secondary filter. We wrote the attached to refresh our memory next time.

Most should be applicable to you. The vent screw on the secondary filter on our engine is hollow. We mark the point to which ours had previously been tightened in order to avoid over-tightening them.

Also we only tighten the filters/drain screw by hand. Some people recommend using more. Others caution against more than hand tight. We did hand tight using a large rubber stretch band for grip. No air leaks yet and engine has run well for several weeks.

[Maka]

I have two Racore filters in sequence. 5 micron filters ,,, same as the engine fuel filter. I plumbed them so I can switch to one filter only and change the other with the engine running.
These Racore's are for a 60 GPH engine... my Perkins 4-108 burns 1 GPH.
Clogged fuel filters should never be a problem.... especially in a tight situation.
I have 4 fuel tanks so all my fuel eventually gets polished by returning fuel to the appropriate tanks.

[barnakiel]

We are talking about two different kinds of prefilling operation. The filters I prefill are the prefillters - the ones that come in between the tank and the manual/mech fuel pump.

There is the mesh on the pump and then the main fuel filter on the engine, so unless one is extremely careless, there are no particles goin to the hp pump.

The other filter - the main one that sits on the engine is downward from the manual pump and this one should NEVER be prefilled. Due to the reasons given above.

Cheers,
b.