Lead additive

[Leo Crowley]

The deceased former and only other owner of my sailboat, a 1981 C&C 30 with an A4 engine left copious notes with the boat. I noticed from these notes that he always added lead to his fuel and this past summer I continued the practice although I am not really sure why this is necessary. Can anyone enlighten me?

[john]

The only additive I've ever seen people recomend for the A4 fuel is Marvels Mystery Oil.

[rblade]

Leo,

Here is a post by Robert Hess
Atomic Four Engine Service
Vancouver, Canada:
Original specification was "standard 92 - 94 octane gasoline", later revised to "regular 90 - 94 octane" (when the specifications were written all gasoline contained lead, which was used to raise the octane rating and extend valve seat life). Modern "Regular" 87 or 89 octane non-leaded gasoline is OK as long as the compression is below 120 psi and the ignition timing is set by adjusting distributor at full cruise speed to give maximum tachometer rpm. Octane booster & lead additive is not recommended or necessary.

Larry