Bleed Screw: Which one is it?

Don S/V ILLusion · Jul 28, 2012

There are 2 bleed screws there: the aft one is the inlet, the forward one is the outlet. The inlet one has a small nylon washer which wears after many bleeds and thus is known to leak. Should be replaced with a new one or a copper crush washer. The outlet one isn't normally bled.

Nom De Guerre · Jul 28, 2012

Scup said:
...on Yanmar 1GM10. See pic.

Which screw is used to bleed the air from the secondary filter, "A" on the left or "B" on the right? No indication in the manual, and most web references are vague.

Click the image to make it big enough to see.

Thanks.

I bleed at B on the right (although on a 2GM, the setup is the same).

Warren Milberg · Jul 28, 2012

I, too, would bleed "A" first and only bleed at "B" if I believed air had gotten into the secondary filter. I also paint the tops of all my bleeds screws, and the positive posts of my batteries, with a dab of red nail polish to make them easier to find in a hurry....

Warren Milberg · Jul 28, 2012

When I replace the filter element in the secondary of my 2GM20F, I fill the bowl about 2/3 full, put in the cartridge, then pour in a bit more diesel to get it as full as possible (I always wind up spilling some....). Screw on the bowl and hit start on the engine. I have never had to bleed the engine due to this procedure even though I agree that it would seem that air would get into the system at the secondary....

kenn · Jul 28, 2012

Scup said:
When you change your [secondary] filter element, how do you keep air from getting in?

When I was working for a mechanic, on Yanmars, we'd just change the secondary filter 'dry', pump that little lever til we saw oil at the bleed screw... then started the engine, and it usually caught and ran fine in less than 10 or15 seconds.

Sandy Stone · Jul 28, 2012

By the way, be careful tightening up the bleed screw. They're famous for stripping out.

Stu Jackson · Jul 28, 2012

When I change my filters, I fill them up with injector cleaner. I find it easier to pour IC into the filters from its plastic container from the auto store than finding clean diesel. Doesn't smell if I drip a few, either.

I find it difficult to understand just how folks get fresh diesel. All mine's in my fuel tank!

Hey, skippers, help me out here: I've never had the guts to ask. Where do you get the "diesel" to fill the empty new filter?

robertsapp · Jul 28, 2012

"B" is your bleed screw. Be careful not to overtighten it, because if you strip it, the filter upper head assembly is pretty pricey. If you want to use injector cleaner to fill your filter bowl, Sea Foam works well. In fact, they recommend filling your secondary filter bowl (the big filter closest to the fuel tank) with it and running it through the engine to decarbonize. Never had the courage to try it though.

Stu Jackson · Jul 28, 2012

Scup said:
Interesting comment, Stu. Thanks. I'm somewhat new to the diesel world (obviously), so what exactly is injector cleaner? I assume it's solvent-based, and a third of a cup of the stuff won't cause my engine any problems, and it cleans out the injector(s). Got a brand name? Is it diesel engine specific, or something used generally on fuel injectors, diesel or gas?

Scup, go to your local auto store. Peruse the shelves through injector cleaners. No difference between gas or diesel, in fact they don't bother to do that. Or, try a truck stop and ask. On a diesel, what doesn't get burned goes back to the tank anyway and you start your engine at or just above idle so you're not burning all of the "incoming."

All U Get · Jul 29, 2012

Stu Jackson said:
I find it difficult to understand just how folks get fresh diesel. All mine's in my fuel tank!

Hey, skippers, help me out here: I've never had the guts to ask. Where do you get the "diesel" to fill the empty new filter?

I filled a gallon gas can with diesel, it takes that amount to do two racor 500 filters. I save the old stuff to filter and run in my backhoe. The local service station will take whatever I don't use.
All U Get

Warren Milberg · Jul 29, 2012

Stu:
I buy "fresh" diesel at a local and busy Hess gas station. I buy it in 2 gal increments, some of which may be used to fill fuel filters when replacing them -- the rest goes into the tank. This keeps the average age of fuel in the tank a bit "fresher." I guess the term "fresh" is a relative term as I believe the stuff at the gas station is somewhat "fresher" than diesel hanging around the marinas for longer periods of time as they sell a lot more of it.

Scott T-Bird · Jul 29, 2012

Buy a SELOC Manual for the right year of your engine ..

It is invaluable and also very clear to understand with photographs and diagrams that will help you perform just about any maintenance procedure. The B screw is the bleed screw. If you look on the cover you can see the arrows indicating inflow and outflow (you can see them in your own picture). Yanmar is consistent ... all bleed screws are a 10 mm bolt with a Phillips head.

I have a 1GM which is essentially the same engine (smaller bore for the piston, though). You also have a bleed screw at the injector pump and I have had to bleed it also on one occasion. That occasion is when I learned how easily the screw can be stripped. If you look at it you will see that bleed screws have a hole through the bolt which makes it weak.

I had a short trip to my slip when I stripped it and there was no wind .... diesel fuel squirted all over the engine compartment during my short trip home. What a mess! Never again will I be caught without a spare ... in fact 2 spares!

Also, Sea Foam seems to be highly recommended. I bought a couple of bottles and was looking at the instructions. It says on the bottle that for diesel, you can add it directly into the filter bowl to get very fast action cleaning for the injector(s).

lehighsail · Jul 30, 2012

When I need diesel fuel, I try to buy it at a marina that has above the ground tanks.
The surveyor I used suggested this and felt that there was less chance of rainwater or ground water getting into the fuel.

Scott T-Bird · Jul 30, 2012

Yes, find any Yanmar parts distributor ... most likely just about any marina in your area that has a service department. You should get to know them well since you will be maintaining a 1GM10!

If you go to the Yanmar website, they will direct you to dealers and distributors.

Stu Jackson · Jul 30, 2012

Many marinas have fuel that "may" not be as fresh as a truck stop. It all depends on where you are. Where I am, our marine fuel stop is the ONLY one left on the Oakland Estuary (the one at my marina closed down a few years ago due to an underground fuel storage leak). This fuel stop gets heavy use and I've never had fuel issues in over 14 years.

YMMV.

Bleed Screw: Which one is it?

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