Volvo 2030 28hp rear engine mounts

I've had the motor out to check installation after 18 years and sure enough the rear engine mounts are 80% 'devulcanised'.

is there a source of cheaper engine mounts than the genuine (win the lottery to afford them) Volvo engine mounts?

Polyflex and Isoflex come immediately to mind - could be worth contacting them.

polyflex.com.au/marine-engine-mounts/search?filter_name=

isoflex.com.au/products/engine-mounts/?gclid=EAIaIQobChMI1eHe_9ai7wIVN51LBR3ahQ1kEAMYASAAEgInZ_D_BwE

Also Headland;

headlandengineering.com.au/our-products/randmarine/

You need the replacement mounts to be equivalent in stiffness, damping and load capacity to the originals so as to not muck up the support and vibration isolation dynamics of the whole assembly. Expect the forward mounts are also needing to be renewed?.

Thanks for the advice; all. !

Ok if it's the rear end that jumps around the most assume you have checked all other possibilities for this result - ie as inferred above coupling damage, also alignment, unbalance somewhere in the drive train including coupling or prop, bent shaft, wear in any bearings, loose bolts, structural deterioration and weakness in bedplate structure and fastenings including holding the mounts, p bracket damage, loose shaft anodes, other. The industry standard for renewal of rotating machinery mechanical components (mounts, couplings, bearings, other) is 12 years. Boat engines don't get utilised as much as the typical rotating machine in a processing plant but at times they are under more adverse conditions.

by 'Jumping around' I just mean that the soft mounts seem to allow that when going in and out of gear and that this must put a strain on them. It runs true in gear. I've gone below and put a stick against shaft when in gear and it's not wobbling.
The mounts are 18 years old. When I originally installed the motor I reinstalled/glassed the p bracket in. 3 years ago I put a new shaft and cutlass bearing in and checked alignment.

I think the reason for the mounts starting to part is simply age but I will be checking alignment and whether the shaft is still true. I wrapped a line around the prop a few years back so I'll be checking that.

I really appreciate everyone's input here. When you're down under the cockpit pulling it all apart you feel like Robinson Crusoe.