Home › Forum › Ask A Member › RDE-18 powerhead to exhaust plate/gaskets › Re: RDE-18 powerhead to exhaust plate/gaskets
The modifications all have their purpose.
If anyone was not sure, the reason for drilling through into the exhaust cavity is for better starts. It relieves some back pressure on the exhaust. WIll the motor still start without this modification? Well yeah, but OMC tried to better the experience of the boater (while limiting warranty work as well of course) by providing these Service Bulletins. In my humble opinion, I would follow each of them, when restoring a motor in question.
In ’57 the RD went to 35hp, which incorporated these improvements.
Then the 1958 RDS 20 is in my opinion the best of all worlds mechanically speaking, as far as a 35hp OMC is concerned.