Bleed Screw: Which one is it?

[FastOlson]

I have crewed a delivery on a boat with a Yanmar three cylinder. When the engine gulped some air (we had it idling during a rather "sporty" bar crossing, just in case...) and died, the skipper bled it with that screw and accidently broke the screw. Turned that that screw was hollow and lots more fragile than he thought. Metric, too, of course.
We sailed 'er into a slip in a crowded marina without crashing--- thanks partly to a role-up jib -- and with some searching around the next day found a solid metric bolt that would make do. After being bled, it started and ran fine.

Just a little bit of trivia about those engines.

 

[Stu Jackson]

That SOLID screw sounds like a good idea. One of our local hardware stores (my favorite marine store, too ) has a great selection of metric bolts, in stainless, too. If I had one of those engines, I'd diss the Yanmar screw and get a few solid ones. Matter of fact, I'd probably only need one.

 

[Scup]

That SOLID screw sounds like a good idea. One of our local hardware stores (my favorite marine store, too ) has a great selection of metric bolts, in stainless, too. If I had one of those engines, I'd diss the Yanmar screw and get a few solid ones. Matter of fact, I'd probably only need one.

Is it fair to assume, then, that the OEM bleed screws are hollow, and with an orthogonal hole near the top, so that when the screw is backed out about a turn or so the air can be bled out through the screw without completely removing it (and then losing it down into the bilge, of course)?

It seems that Yanmar made the trade off is between a "semi-captive" but weak screw vs. a strong, but "lose-able" screw.

 

[Rob2435]

It's "A" - did I win anything?

 

[Scott T-Bird]

Rob, if you think the bleed screw is A, you need to study the Yanmar manual a little more carefully.

Scup, yes, that is the trade-off.