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shift cable lower tap size - new cable brass facing fwd

FstaRockr Burns

FstaRockr Burns

Regular Contributor
Hi there, ordered a new bellows kit and lower shift cable. The one I took out had the 9/16 brass nut facing fwd, however on the new cable its facing aft.

Now ive searched all over and see alot of reference to the 1/4- nptf straight tap, but in my mind I need to tap the large brass section? Am i missing something?

Current setup: transom - lower 9/16 nut | threads facing back (screws in from the front)

New cable: transom - threads | brass nut (screws in from rear)


It seems I would tap the current threads from the front thru to the rear so I can screw in the brass fitting from behind?
 
No and no and no.

Use a standard 1/4 npt tap. Start tap from inside gimble hoising tapping hole so cable installs from inside gimbal housing.
Tap hole at least 3/4 of threads on tap. Do a test install to make sure that when tightened the hex head is ~ 1/16 of an inch from gimbal housing wall.
A special lenght tool is needed to tighten cable into gimbal housing. A standard 9/16 six point deep well socket is not long enough. You need a socket or hollow extension at least twice as long as a deep well socket.
I have drilled out a 3/8 3 inch long extension (1/4" drill) to get the depth/ length needed. The little spring ball needs to be pryed out as it is very hard and will ruin the drill bit.

So you have to install from inside gimbal housing...no other choice...that is how it is designed and has been for over 30 years.
 
Jack, that not right . A pipe tap is not a straight tap.
There is no brass section to tap. with the old cable removed is the aluminum housing only.
If you see brass remaining you left part of the old shift cable still in there.
Get the correct tap and drill size for 1/4 inch pipe thread.
See page 4A-17 in here http://www.boatfix.com/merc/Servmanl/6/6A4R3.PDF
 
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The threaded hole is NPT threads as I said. So a standard 1/4 NPT tap is what is used...the threaded section of the cable is NPT threads.

If he left some of the brass behind then YES drill out with proper drill and then simply tap hole from inside housing side with NPT tap.
 
pipe threads , yes but not a standard pipe tap. pipe taps are a tapered thread . shift cable threads are a straight thread, not tapered
If you have a friendly welder, weld a donor socket to a deep thin wall 9/16 socket for the cable install tool
 
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BT,
I have to dissagree.
I just looked and the cable threads are tapered. If this was not the case there would be a leak due to the straight threads.......so a standard npt tap can be used.
 
mercruiser 1/4 inch pipe thread srtaight tap on left, 1/4 inch pipe tap on the right .Clearly you can see the taper. If you bottom out the pipe tap,the housing is trash brcause the hole it too large.
You may get away with it IF you dont sink it too deep but why take a chance
DSCN4142_zpsm1ttbdz0.jpg
 
Ayuh,..... I'm gonna sorta agree with Both of ya,.....

While the 1/4" pipe thread straight is the proper tap, as noted in the factory manuals IS in fact the proper tool for this job,...

The standard 1/4" tap, tapered can be used to clean up or possibly cut the threads needed,...
Problem is, go to deep, 'n yer Done,.... No joy,.....

Btw,.... After I welded 2, 9/16" Snap-on deep sockets together, I discovered the new cables don't need it,....

The little white plastic piece that's in the way,....
Simply unscrews from the new cables,... then screws back in,.... with yer fingers,....
 
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