Broken Speedometer Nipple LowerUnit

[HeavyD52]

I have a 2000 Yamaha OX66 150HP. I was changing the water pump and broke that plastic nipple that the speedometer tube connects to. In the process of digging it out of the hole, I boogered up the threads. Anyone know what size those threads are? Thinking I will need to run a tap down there to clean it up. Appreciate any help or ideas.

[TownsendsFJR1300]

I'd get the new, replacement part, head to the hardware store and check thread size/pitch with the proper gauge (or a nut).

You'll now know what exact size it is and you need the new part anyways..

[HeavyD52]

Yes, that was my fall back plan. I will have to get the new part. I'm assuming it's a metric thread and since there aren't a lot of metric taps easily available I was hoping someone might have that answer at their fingertips. This seems to be a pretty common issue.

[TownsendsFJR1300]

Not really a common issue, but S... happens.

Someone might know but your post is the first I've read here asking...


Think this is the correct one: http://www.boats.net/parts/detail/ya...378-00-00.html


Good luck.


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[panasonic]

The nipple has tapered pipe thread on it....so I would assume the hole that it screws into is also Tapered pipe as well. Now it being a Yamaha I have no idea what size it would be... cause everything is metric.

So you will need a tapered pipe tap the correct size and pitch.....hmmm

What size hex is on the nipple...10mm 0r 12mm?

[TownsendsFJR1300]

If the threads are not too terribly boogered up, perhaps some good teflon pipe tape on the fitting to help it turn into the "iffy threads"?

There's not a bunch of pressure on it and your just tightening it down till snug..

A quick peek on Flea Bay, : http://www.ebay.com/itm/HSS-M1-M16-I...QB6JTeWbUvhdLQ

Tapered, metric taps are pretty common...

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[pstephens46]

If the threads are not too terribly boogered up, perhaps some good teflon pipe tape on the fitting to help it turn into the "iffy threads"?

There's not a bunch of pressure on it and your just tightening it down till snug..

A quick peek on Flea Bay, : HSS M1 M16 Industrial HSS Metric Taper Plug Tap Right Hand Thread Drill Bits Set | eBay

Tapered, metric taps are pretty common...

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Betting the teflon tape idea will work. As long as it goes in straight you should be good to go. Not a pressure fitting. Not really...

[99yam40]

should not be many different metric pipe threads, so should be easy to find what is needed

[panasonic]

There isn't really a "metric" tapered pipe thread as far as I can tell. The Japanese adopted the BSPT "British Standard Pipe Thread" for their manufacturing. From looking at the fitting in the parts picture Scott posted and I had one out good while ago.... I "think" it is an 1/8" -28 BSPT thread on the fitting.

1/8" British tapered pipe threads will have 28 thread/inch, vs. 27 threads/inch for NPT (standard). Pitch diameters at the small end/lead thread are within a few thousandths of each other. The other big difference is the thread form (55 degree Whitworth vs. 60 degree sharp vee).

Here is the tapered tap from my Blue Point "metric" tap set.

I would get the fitting in hand and check the threads per inch with a thread gauge and then source the tap, Maybe Mcmaster-Carr?

Maybe call Yamaha tech support?

[panasonic]

If the threads are not too terribly boogered up, perhaps some good teflon pipe tape on the fitting to help it turn into the "iffy threads"?

There's not a bunch of pressure on it and your just tightening it down till snug..

A quick peek on Flea Bay, : HSS M1 M16 Industrial HSS Metric Taper Plug Tap Right Hand Thread Drill Bits Set | eBay

Tapered, metric taps are pretty common...

.

Scott,
the end of the barbed fitting with the threads is tapered, think air hose fittings, pressure gauges, brake line fittings, ect ... So the hole that fitting screws into is tapered as well. The fitting wedges itself in hole as it tightens...self sealing.

Those "tapered" taps on EBay are just for straight thread holes but with a taper on the end to help start the tap square in the hole when threading..

[panasonic]

Good tap sets have three of each size tap, for example see the picture for a 5/16"-24 UNF tap.

There is the Taper (or starter tap), the plug tap (middle) and bottoming tap (to get down to bottom of blind holes)

Most tap sets only come with a plug tap for general use in each size....

[TownsendsFJR1300]

Scott,
the end of the barbed fitting with the threads is tapered, think air hose fittings, pressure gauges, brake line fittings, ect ... So the hole that fitting screws into is tapered as well. The fitting wedges itself in hole as it tightens...self sealing.

Those "tapered" taps on EBay are just for straight thread holes but with a taper on the end to help start the tap square in the hole when threading..

Yep, that one link looked like a regular tap VS yours which is VERY, obviously tapered.

I agree it should be self sealing (and no tape/sealer needed). Just being used strictly for "lubrication purposes" to limit damage to the new plastic fitting going into "dis-figured" threads...

And if that is the correct fitting (the link I posted), that fitting isn't very tapered at all.

[99yam40]

I do not remember seeing 3 different pipe thread type of taps in sets here in the USA

[panasonic]

Yep, that one link looked like a regular tap VS yours which is VERY, obviously tapered.

I agree it should be self sealing (and no tape/sealer needed). Just being used strictly for "lubrication purposes" to limit damage to the new plastic fitting going into "dis-figured" threads...

And if that is the correct fitting (the link I posted), that fitting isn't very tapered at all.

Take another look, its a "Tapered Pipe Thread" on the end of that fitting. I had one of those out on my brothers F60 two months ago....99% sure.

So the hole it screws into will be a Tapered thread, created using a Tapered Pipe Thread tap of the correct size.

That is what I am trying to determine...what size? When it comes to tapered pipe fittings things get weird.

[panasonic]

I do not remember seeing 3 different pipe thread type of taps in sets here in the USA

Yes you are right, the taps in the first picture are all the same size 5/16"-24 UNF, for cutting straight threads, no taper.

They just have different ends on them for starting the thread, through hole or bottoming hole. They are not Tapered Pipe Taps.

The second picture is a Tapered pipe thread tap.