Timing for 1986 140 hp Mercruiser & Bottom plate replacement

[D. Engstrom]

Boat: 1986 Sea Ray 140 hp Mercruiser with engine serial # A611762. Alpha 1 drive.<br /><br />Three questions. Is the timing for this engine 6 degrees BTDC or 8 degrees BTDC at idle? The engine label says 6 but I have seen 8 floating around. Another question regarding timing - is it checked off of the #1 spark plug or off of the coil? <br /><br />Last question, is it recommended to replace the bottom plate of the water pump in the outdrive when putting a new water pump kit in. I have been told that unless the outdrive overheated the bottom plate would not need to be replaced. I would think that if there are oil seals in the bottom plate that it should be replaced also.

 

[Trent]

Re: Timing for 1986 140 hp Mercruiser & Bottom plate replacement

Just for your info. The reason you have seen both is that the 120HP is 8 btdc and the 140 is 6 btdc. Timing is checked off of the #1 sparkplug.<br /><br />The bottom plate of the waterpump should be replaced every now and then. They tend to get scored up over time. And yes the seals below the bottom plate should also be replaced and the shift shaft seal also. This is really your choice when to do it, unless they are leaking. I like to recommend every 6-8 years if they are not leaking.