Which is the Bleed Screw - 2GM20 Fuel Filter

[Wotname]

Yanmar Quiz Time.

The photo is from a 2GM20 but I sure it applies to the GM series and maybe other Yanmar series.

Vote and discuss (if you must )

[sailorchic34]

Officially its the small screw, that the yanmar engineers then located directly under the exhaust manifold. The bigger screw oddly will work for bleeding too. Because a good engineer always allows for a backup.

[Wotname]

145 views and only four votes...
Maybe a boring poll or maybe no one wants to use option 4

While the other low pressure bleed screws are characterized by the Phillips Heads, at the this point you get an option of a slotted head. More back up I suppose .

I have never bothered to look closely but are the screws on either side of the filter element and would it matter anyway?

[Wotname]

Originally Posted by sailorchic34

Officially its the small screw, that the yanmar engineers then located directly under the exhaust manifold. The bigger screw oddly will work for bleeding too. Because a good engineer always allows for a backup.

At least the access is good (even great) on the 2GM20 unlike say 3GM30F and presumably the 2GM20F.

[RainDog]

I always use the big one.

[Wotname]

Well the big one is slightly higher than the small one so using the big one is better in principle!

And easier to use with a socket if you are like me and prefer sockets to screwdrivers!

[BobL]

I have a 1gm10 and the manual says the small phillips head is the proper one to use for bleeding the line.

Bobl

[four winds]

10mm wrench fits the smaller "air bleeding bolt" as the manual calls it. It has a slot cut through the threads to help the air escape. Barely has to be loosened as a result. The nylon sealing washer will distort very easily. So don't over tighten. Good part to have in the spares box I think. Especially if you mistakenly remove the bolt entirely and drop it in the bilge like I did. Have no idea where that thing went.

The larger bolt is referred to as a "plug" in the manual diagram. No mention of it in the text that I see.

The sealing surface of the larger bolt is no higher than the bleeding bolt on my filter body.

[laika]

What about the 2nd (or "3rd") bleed screw? Where's that little dude at, eh?

[sailorchic34]

Originally Posted by laika

What about the 2nd (or "3rd") bleed screw? Where's that little dude at, eh?

The second bleed screw is on the end of the bolt that connects the fuel line to the injector pump, which the Yanmar engineers put under the tank on the fresh water cooled gm's. Another fail....

[Roy M]

I have a long slotted screwdriver in my engine room that just fits perfectly. Both of the two screws on mine are hex, but the slotted is much larger and accessible.

[Wotname]

Originally Posted by four winds

10mm wrench fits the smaller "air bleeding bolt" as the manual calls it. It has a slot cut through the threads to help the air escape. Barely has to be loosened as a result. The nylon sealing washer will distort very easily. So don't over tighten. Good part to have in the spares box I think. Especially if you mistakenly remove the bolt entirely and drop it in the bilge like I did. Have no idea where that thing went.

The larger bolt is referred to as a "plug" in the manual diagram. No mention of it in the text that I see.

The sealing surface of the larger bolt is no higher than the bleeding bolt on my filter body.

I always assumed (probably incorrectly) that the "plug" is provided as another outlet of the fuel filter - not that I can see any need for such but maybe ultilized in some rice harvester or such like in Japan.

[four winds]

Originally Posted by Wotname

I always assumed (probably incorrectly) that the "plug" is provided as another outlet of the fuel filter - not that I can see any need for such but maybe ultilized in some rice harvester or such like in Japan.

Sounds reasonable, and simply "plugged" for marine use.

My first guess was it was used during machining operations to drill the fuel pathways and then plugged. Though usually those are simple pressed in plugs or peened on ball plugs. Common on many carburetors.

[bill good]

Just a little side note on this over priced little bit of kit. I found both my 1GM's had banjo bolts which were too long & had always problems with getting any washer to remain sealed until they were shortned. Always had a bit of diesel showing before this mod. Even purchased new filters in the process.

Bill

[Wotname]

Originally Posted by bill good

Just a little side note on this over priced little bit of kit. I found both my 1GM's had banjo bolts which were too long & had always problems with getting any washer to remain sealed until they were shortned. Always had a bit of diesel showing before this mod. Even purchased new filters in the process.

Bill

Curious.

Did you ever try new washers or even two washers per bolt?

I will store this snippet of info for furture consideration as I always had the faintest screen of diesel on the bottom of the filter. Not really moist or damp but always returns after awhile no matter how well cleaned off.
Thanks for the heads up.