Help! I've not had one of these before, but my new chummy has a speedo driven off the prop shaft. (As it should have). Problem is the speedo is wildly out of calibration. I've not checked it but it feels like it's reading double.
Question is, is the drive ratio the same as the gearbox driven speedo that followed, or is it something different?

Not absolutely sure but I think the speedo should be an A which rotates at 3360 TPM whereas a PA as fitted to the g/box drive is 2240 TPM.
A belt driven speedo calibration can be wildly out dependent on the belt pulleys which I think should be 55mm on the prop and 60mm on the cable driver bit.

Location: Channel Islands

Thanks, that sounds about right. I guess I could correct it by fiddling with pulley sizes.