The cooling issue may well be a degraded water tube grommet/seal. The opening on the grommet is very small, and an old grommet can even swell blocking off the cooling water.
Most of the time, the grommet can be replaced without loosening the gearcase screws, but not always.
The pin that drives the eccentric, is just pressed in and usually easy to remove.
Improvise-Adapt-Overcome
