Performance Cruising Gemini 105Mc - Removing the Sillette Drain Plug

Gemini 105Mc Owner’s Manual
52Copyright © 2004 Performance Cruising Inc.
Removing the Sonic Drive Oil Drain Plug
Sillette-Sonic Ltd
182 Church Hill Road, North Cheam, Sutton
Surrey SM3 8NF United Kingdom
+44 (0)20 8715-0100
sales@sillette.co.uk
http://www.sillette.co.uk
1. The plug located in the skeg is ¼” BSPT (British Standard Pipe Thread) and uses a ¼” A/F hexagon Al-
len key to remove. You should use a key with at least 6” / 150mm of arm and not the cheaper short se-
ries key with only 3”/75mm of arm. Sillette can provide a long series set for $23.00 plus shipping and
taxes
2. To remove – clean the area around the plug using a wire brush. Insert and fully locate ¼” A/F Allen
key and unscrew counter-clockwise.
3. If resistance is too great to unscrew, use a steel punch 7/16” / 11.5mm diameter about 4” / 100mm
long, preferably with a raised point one end 3/16” diameter to roughly locate in the hexagon hole.
Then, using a large engineers or club hammer, while holding the punch with mole grip or pliers, and
while supporting the opposite side of the drive leg, holding the punch firmly against the face of the drain
plug and with a firm and determined force, strike the punch with the hammer. This may be repeated
several times. After each blow, re-insert the Allen key and attempt to unscrew. Do not strike the Allen
key with the hammer as this has little affect and usually damages the hexagon in the plug.
4. If the process fails to remove the drain plug, then apply heat to the aluminum around the plug until
warm to the touch to encourage it to expand. Note if you heat the plug, the heat will cause it to expand
and become even tighter in the aluminum. Then repeat step 3.
5. To drain the oil, it is necessary to remove the filler plug #616/30, which is located on the top of the
leg.
6. When refitting the drain plug, use PTFE/Teflon Tape and keenol grease on the threads. Centralize the
taper plug into the hole and turn clockwise. Resistance should be light until fully inserted. Note – the
taper plug is difficult to cross thread accidentally as the plug draws itself in on the thread when turned
clockwise. Do not use copper based anti-seize compounds as this causes corrosion in the salt water envi-
ronment.
Comments:
Sillette has never failed to remove a drain plug by methods 2, 3, or 4 unless the hexagon had been previ-
ously damaged.
If the hexagon is damaged, the plug can be drilled out using a masonry drill (carbide tipped or similar).
Use at slow speed with plenty of coolant. Start with a small size, gradually increasing to 3/8” / 9.5mm.
The remainder of the plug can usually be removed by using an “EasyOut” (tool with a left-hand spiral –
available from any good tool supplier). If, however, you do not succeed with an “EasyOut”, continue
drilling to 11.5mm diameter and clear remaining plug material using a ¼” BSPT or ¼” NPT tap. Ensure
twist drill remains central and square when drilling. The oil usually flushes out the drillings. If in doubt,
flush through with more oil.
If the thread is damaged, re-drill to 15mm diameter and re-tap 3/8” BSPT/NPT and fit oversize 3/8”
BSPT/NPT taper plug.
Remember, “On Board Spares Kit”, spare drain plugs, and the correct Allen key set are available from
Sillette.
Sillette uses a nickel plated high tensile steel taper plug and have done so since 1975. The plug causes
less corrosion to the aluminum and the hexagon socket is stronger than stainless steel. Once removed
and replaced for the first time – fill the end with silicone and allow to cure which seals off the plug from
the marine environment. Consider replacing every two years. A4/316 stainless plugs are available, but
remember they are less durable and react more with the aluminum skeg casing.
Removing the Sillette Drain Plug