Originally Posted by lenganote
Rob,my Morgan NM 45 is hull #16 and is an IOR hull,deep draft
,with a cruising interior
. Engine is Universal M40 and the tranny is a Hurth HBW 150V.
The prop shaft no longer turns while in gear with engine running,so I cannot figure out how to calculate gear ratios.
We dodged a bullet yesterday when the Tsunami hit our harbor in Honolulu where she is berthed. Thankfully,she suffer no damage.
The gear ratios on the Hurth 150V on my engine are A 2.13, B 2.22.
The Universal M40 is rated at 32HP, the Perkins
4-108 rated at 50hp; the 150V on my boat has a side-attached aluminum
box through which is pumped sea water
to cool the transmission - your setup may not require that additional transmission cooler.
If you're going to replace the transmission then you're going to have to remove it from the motor's bell housing - if you do that now you can then rotate the tranmission and work out the existing gear ratios (unless it's welded itself together inside or the clutch
plates are gone in both forward and reverse).
Personally I would tend to disregard whatever the original builder
did and talk with the engine manufacturer to find out what they would do today - which might be different than what they did when the engine was originally put in the boat.