Dropped a straw in my gearbox!!!!

[Boatwright]

I like the idea of stabbing it with a straightened fish-hook. Be careful when you make the tool - don't lose the fish-hook too.....

My ideas:

1) Make a noose out of fine copper wire projecting out of the end of a small tube long enough to reach into the filler hole. Lasso the straw, draw the noose tight by pulling the wire from the outside end, and bring the lost tube up to the filler hole. Maneuver the lost tube to where you can grab it with needle nose pliers.

2) For all suggestions, get a hemostat. I have bent the shafts of SS hemostats inward to narrow the clearance required to open and close. You can do this by heating the metal red-hot with a propane torch. SS does not lose lose its temper like regular steel when heated. You may be able to use the hemostat all by itself, or as an aid in maneuvering the straw to the fill hole.

More than one mechanic (me) has placed a rag in the carburetor throat when working on an engine, cranked it over, and sucked the rag through the engine. A bit of valve clatter and she runs fine. I wouldn't however think it wise to grind up a semi-hard plastic tube with your transmission.
Good luck.

[Swift Drift]

Originally Posted by jamhass

While you have the side cover off, check the oil cooler for corrosion, since it is now where you can inspect it.

Well, during reassembly I snapped off the petcock drain at the bottom of the oil cooler. I was able to extract the remaining section and chase the threads in the cooler with a tap so they are good and clean.
Now I need to make a decision on what to plug the hole with. I’m tempted to use a stainless bolt with some tef-gel or lock-tite on it. But I’m concerned about the whole dissimilar metal scenario.
Am I making a bad decision by going with a stainless bolt? I think the cooler is bronze? Pretty sure the old corroded petcock was brass.

[a64pilot]

Usually they aren’t machine threads, often they are NPT.
If it’s machine threads then I’d use a bolt with tef-gel with the intent of changing it later with something bronze, if it’s NPT, then I believe I’d be tempted to use a PVC plug if you can find one, there is no real pressure there, and brass as a last resort, with the intent of later putting on what’s supposed to be there, surprised if it was brass.
I don’t have a cooler, but there are I believe similar drain pet docks on the heat exchanger and a couple of other places on the engine, one is I believe plastic.

Yanmar May also have used a wierd British thread, but I don’t believe this is really a Yanmar transmission, maybe not.
My 4-JHE uses this weird British thread on its oil galley plugs, I ran into that when installing an oil pressure gauge.

I think the KBW-20 is a Hurth transmission built under license?

[mvweebles]

SS bolts are used to secure bronze thru hulls frequently, and salt water is a better conductor than oil. You may eventually have an issue, but will take a long time.

Any idea what material the bolts that secure the cooler in place are made of?

To the forum - if the cooler is bronze, would a brass plug be preferred to stainless?

OP: your heart must have dropped when you heard the Crack of metal breaking. I really admire your tenacity. True cruiser mentality.

Peter

[mvweebles]

Originally Posted by a64pilot

Usually they aren’t machine threads, often they are NPT.
If it’s machine threads then I’d use a bolt with tef-gel with the intent of changing it later with something bronze, if it’s NPT, then I believe I’d be tempted to use a PVC plug if you can find one, there is no real pressure there, and brass as a last resort, with the intent of later putting on what’s supposed to be there, surprised if it was brass.

Good point on NPT vs straight thread. Sounds like OP chased with a tap of some sort so maybe he knows. Agree that this may very well be NPT.

Seeks odd to put a pet cock here vs a well protected hollow banjo bolt. But so be it.

[a64pilot]

I’m thinking it’s a drain that’s in the water jacket, not the oil side, so it’s exposed to salt water if I’m right.

[Compass790]

[QUOTE=Swift Drift;3136680]
Now I need to make a decision on what to plug the hole with. I’m tempted to use a stainless bolt with some tef-gel or lock-tite on it. But I’m concerned about the whole dissimilar metal scenario.
Am I making a bad decision by going with a stainless bolt? I think the cooler is bronze? Pretty sure the old corroded petcock was brass.

I believe ss is fine with bronze. Many bronze HX have ss bolts. Think they are close in galvanic table.

[Swift Drift]

Originally Posted by a64pilot

I’m thinking it’s a drain that’s in the water jacket, not the oil side, so it’s exposed to salt water if I’m right.

That is correct. As for machine threads vs NPT, I am not sure. I chased it with an “M8 x 1.25” tap and it threaded nicely.

It sounds like stainless with Tef-gel would work fine provided I use the correct threads.

The mounting bolts appear just normal steel bolts by the way. However they do not come into contact with raw sea water.

[Wotname]

FWIW, all the Yanmar petcocks that I have ever seen have had BSP threads.

Technically they are JIS threads but JIS is interchangeable with BSP for all intents and purposes.

[Wotname]

Also FWIW, many (but not all) Yanmar heat exchangers use cupronickel. It there is no anode in the system then I would bet it is cupronickel.

[Smokeys Kitchen]

Simple reply for this thread:

Glad you got your problem (at least the original one) solved and thank you very much for posting the result. Too often we are left wondering "what happened"?

[a64pilot]

I would likely use an M8 bolt with Teflon tape and not make it real tight, cause I don’t think that’s the right thread, but so long as you don’t make it so tight it deforms the threads, no harm. This thing is under about zero pressure, there is some, not much so I don’t think you need any super tight seal. Then get somewhere where you can get the right part and see how well it fits, pipe threads of course are a little bit of an interference fit anyway.
I’d use Teflon tape cause it may seal a leak better than Tef-Gel and ought to be OK.

I think this transmission isn’t really a Yanmar? I know it says Yanmar on it, but I think it’s a Hurth? I say that as maybe the thread is different than what Yanmar uses in the engine that they build.

[Swift Drift]

Originally Posted by Wotname

FWIW, all the Yanmar petcocks that I have ever seen have had BSP threads.

Technically they are JIS threads but JIS is interchangeable with BSP for all intents and purposes.

Thanks for the insight. I’ll keep this in mind when trying to source a plug tomorrow.

[Swift Drift]

Originally Posted by a64pilot

I would likely use an M8 bolt with Teflon tape and not make it real tight, cause I don’t think that’s the right thread, but so long as you don’t make it so tight it deforms the threads, no harm. This thing is under about zero pressure, there is some, not much so I don’t think you need any super tight seal. Then get somewhere where you can get the right part and see how well it fits, pipe threads of course are a little bit of an interference fit anyway.
I’d use Teflon tape cause it may seal a leak better than Tef-Gel and ought to be OK.

I think this transmission isn’t really a Yanmar? I know it says Yanmar on it, but I think it’s a Hurth? I say that as maybe the thread is different than what Yanmar uses in the engine that they build.

This could be my best option given the circumstances. I was able to easily thread what I think is an M8 from my random onboard bolt collection. It did however have a slight wobble to it, indicating it isn’t a perfect match. The wobble was small enough that Teflon tape could easily snug up.

[Swift Drift]

An interesting point of clarification that doesn’t directly help my situation at hand but wanted to pass on: I’m thinking I have a KBW 21 rather than a KBW 20.

It seemed fishy that mine has the oil cooler system and no other kbw 20’s seem to. I have however seen pictures of kbw 21’s and they have an oil cooler.
I originally thought I had a kbw 20 because of the lower stamp in the below pic that says “KBW 20”. However, the upper labeling clearly identifies it as a “KBW 21.” Confusing but my hunch is that the presence of the oil cooler confirms KBW 21.