Post by native77 on Oct 10, 2014 6:26:43 GMT -6
Oct 10, 2014 6:13:59 GMT -6 @poerover said:
The gear ratio for Johnson/Suzuki four strokes in the 90 to 140 class I thought were the same at 2.38 to 1. Johnson/Suzuki relationship went away when Etec came out. I could be wrong but did not think Suzuki in the 90 to 140 class upgraded gear ratio to 2.59 until last couple of years after 2009. I looked at Merc prop selector site and put in 90 HP and it said 90,115, 140 all 2.59 for engines all about same time period in the 2003 to newer. Put in just my engine at right year and it came 2.38. I don't know but find it strange that gear ratio would be that different for about same era engines. No matter and not trying to be-labor a point even manual does not state ratio. Native glad you are hitting those performance numbers no matter what the gear ratio is. Merc prop selector on my setup suggests between 21 to 22 pitch prop but go down in diameter to 13.25 to 13.5 to achieve theoretical speed of about 46 mph for general purpose use. It referenced Laser II and Vengeance. Vengeance props I think look similar to my OEM prop. Laser II slightly less diameter in blade shape.
I have an identical spare stainless steel prop that was original with boat that has a slight ding on a blade tip. Got a new exact same prop when bought boat not thinking about changing sizes at that time. May take that spare prop to get a look at and see if they can change pitch or maybe add a bit more cup to prop.
As as best I can tell. Dia has little effect in rpm changes, some but not a lot. Dia does effect performance Small dia big boat is a bad combination. I have been down that road.
If your not over/under revving and your slip is acceptable, not much more to do but fish and cruise. 239_fishing icon_captain
Be be safe out there.