Originally Posted by Cpt.Steve
** For others who have gone from a 4108 to a modern 50hp. Did you have to go up in prop shaft size? What did your reps suggest? Our new boat
was soec’d with a 1” shaft for a 4107/8 with 2:1 reduction (BW vd to a Walter V). Curious if anyone is running a 1” with 45-50+ hp. Thanks
When I replaced my 4-108 with a BV2203 (Beta 50) the factory said my 1-1/4" shaft was marginal. I kept it and it was fine. But 1" is too small. I'll bet you never drove that 4-108 to full power. Your prop is probably undersized for that engine
. If you were able to get the 4-108 close to 4000 rpm
you were never really loading it up, I couldn't get it up to 2200 so my installation
was the opposite.
If you were never using all the power of the 4-108 you don't need a Beta 50. The Beta factory suggested I only needed a Beta 43 to replace the 4-108 but my boat
(44 feet 12 tons) was underpowered.