Yanmar 2GM20F fuel filter maintenence

[paulg222]

So I'm a total newbie to maintaining diesel engines, so apologies in advance if these are dumb questions.

For changing or cleaning the primary (smaller) fuel filter (recommended to clean every 50 hrs), do I need to shut off the fuel supply from the fuel tank first?

Seems like I should to prevent the whole system from draining out but I don't see this mentioned in videos on youtube. Then to get air out I suppose I re-open the fuel supply first before trying the manual pump to prime it, right?

Secondary filter:
To just drain water from a Racor filter I can just open the screw at the bottom, right?. I've heard that this procedure does not require fuel supply to be cut off first. Do I need to open the bleeder screw at top for this procedure? Do I need to do any bleeding or priming after that? Replacing it is different but just want to drain water for now.

[paulg222]

Also I may have gotten primary and secondary mixed up above I'm actually not sure which one is considered primary. Anyway the smaller one is what I call primary above and is what is recommended to clean or change every 50 hrs according to manual.

[Cat36Mahalo]

The primary is closest to the tank - your Racor. You do not need to turn off fuel or open top to drain water

50hrs seems very short. I change my primaries when the pressure across the element is high (determined with vacuum gauge. Probably every 250hrs. I change secondary every 2-4 primary changes or every 3 years. And I do turn off fuel when changing either filter

[sailorchic34]

50 hours would be short even if that was the only filter. With a racor upstream, doing all the heavy lifting, you can easily go 3 years on the dinky engine mounted filter. Less bleeding / cuss'n that way.

[dennismenace111]

A whole lot less cussing! I bought a new Racor with an integral pump. I can actually bleed all the way to the injectors now. Makes for alot less mess and diesel stink in the engine dungeon!

[Boatyarddog]

Originally Posted by paulg222

Also I may have gotten primary and secondary mixed up above I'm actually not sure which one is considered primary. Anyway the smaller one is what I call primary above and is what is recommended to clean or change every 50 hrs according to manual.

Primary filter is 10 microns, 2 micron is the secondary.
Secondary is the one mounted on the engine.
Unscrew the ring on the filter housing, lower the fuel bowl, the filter is in there.
Replace the filter and the o-ring.
Insert the filter in the housing fill the housing to the top with clean diesel fuel.
Rescrew the ring to the filter housing.
Bleed the air outta the housing by loosening the bleeder screw on top of the housing and use the fuel pump lever at the bottom of the pump to push the air bubbles out thru the bleeder screw hole, till no more bubbling just clear fuel, about 5 to 10 strokes of the pump lever.
Then retighten the screw and start and run 5 or 10 minutes, to be sure it doesn't stall on you.
If it stalls be sure to bleed the system again, if you get air and it won't start, be sure to slip the raw water pump belt to keep water from backing up the muffler and Hydrolocking the engine.
You can also shut the raw water intake as well.
Be sure to open it again and check for water flow when she restarts.
Cheers,
SV Cloud Duster

[Cheechako]

I'll just add that when changing filters, you can often save yourself some problems by filling the filter housings with diesel while putting it back together.
Be careful that after changing filters, you may run the engine for a few minutes and think things are fine. Next time you leave the marina and half way out the engine dies!
These engines use very little fuel and the system may work for a while then get system air in and kill the engine!
Run the engine in gear for a while at the dock.

[Secondshift]

The Clymer manual for the GM series states clean at 50 hrs replace at 250 hrs
I believe this is specified for a stand alone filter without the Racor.
As others have mentioned it would be excessive with the Racor.

If your getting a lot of water you may want to polish your fuel and clean the tank.

Regards

[Compass790]

do you know what microns your Racor is?
The Yanmar little filter is 10 micron. You can get generic replacements much cheaper. Agree with others depending on what your primary Racor filter ( 1st one after tank) micron rating is you could go for years without changing yanmar one.

[Boatyarddog]

Originally Posted by Compass790

do you know what microns your Racor is?
The Yanmar little filter is 10 micron. You can get generic replacements much cheaper. Agree with others depending on what your primary Racor filter ( 1st one after tank) micron rating is you could go for years without changing yanmar one.

My 2gm20f ran a 2 Micron filter element in the engine mounted secondary filter housing.
The primary was a 10 micron.
There may be different filtration options.
SV Cloud Duster

[Compass790]

Originally Posted by Boatyarddog

My 2gm20f ran a 2 Micron filter element in the engine mounted secondary filter housing.
The primary was a 10 micron.
There may be different filtration options.
SV Cloud Duster

Ok that's interesting. I was told the Yanmar one was 10 micron but it could be parts assistants error.

[Wotname]

Originally Posted by Boatyarddog

My 2gm20f ran a 2 Micron filter element in the engine mounted secondary filter housing.
The primary was a 10 micron.
There may be different filtration options.
SV Cloud Duster

Originally Posted by Compass790

Ok that's interesting. I was told the Yanmar one was 10 micron but it could be parts assistants error.

I have never been able to find any documentation describing micron rating of the Yanmar engine mounted fuel filter as fitted to the GM series engines.

I would love to see some!

[GordMay]

For Fuel System (filtre change/bleeding), see pages 47 & 48
Yanmar Workshop Manual ➥ http://j30.us/files/YanmarGM&HMWorkshopManual.pdf

[Compass790]

Originally Posted by Wotname

I have never been able to find any documentation describing micron rating of the Yanmar engine mounted fuel filter as fitted to the GM series engines.

I would love to see some!

Can't find actual Yanmar spec Wotname ( Doubt they make their expensive filters anyway ) but this is a replacement for that part no. & Donaldson would claim to meet or exceed Yanmars spec. Interestingly it's 16 micron, more coarse than I would have expected for a final filter. Glad I've substituted a 5 micron one for Yanmars then

https://shop.donaldson.com/store/en-...estid=3943509#

[a64pilot]

I’ve not found a spec for a Yanmar final filter either.
However the primary is usually spec’d for a 30 micron, a few will run a 2 micron thinking they are doing good as fuel can’t be too clean and if you supply the secondary filter with fuel with nothing larger than 2 microns, it should never need changing.
However a 2 micron may cause more restriction than the mechanical fuel pump can handle.

Donaldson’s are excellent filters, I’d be very surprised if their filters aren’t better than whatever Yanmar has been buying.