Steve.

ANSWER

Dear Steve

In view of the inherent dangers of petrol boats and the increasing chances of litigation I regret that I am very unhappy about trying to support petrol engines unless I KNOW the capabilities of the owner.

However, as you only ask about the ignition system, and you know about dwell, I will give the best answer I can.

It all depends upon which Lucas distributor is fitted, but in all honesty I do not see how any gain made by using dwell rather than point gap will be worth the effort on such an old engine.

If the distributor is so worn that you can not set the gap with a feeler gauge I think the advance springs and mechanism would be worn, as would the rotor air gap, so a new distributor would be a much better bet than trying to set the dwell.

I think the Lucas 25D distributor has a dwell of 57 to 63 degrees. This is the one I think you will have. It has a very domed cap, rather than an almost flat top to the cap.

Tony Brooks