-
Lost rpms when changing lower unit (4.75)
I recently had to get a new lower unit due to destroyed gears. I had a smaller 4.25 size lower unit prior with a 24p tempest plus II. I used to be able to turn 5700 rpm and high 50's on my 1990 ranger 482 with 95' 150 xr6. My new Lower unit is a larger gear case (4.75) and using the same prop. Now I can only turn 5100 rpm and max out at 52mph. I know lugging these motors is not good and I believe that's what he m doing The motor runs fine but I would love some suggestions/information on what may have happened. Is it that the prop is too small?, diameter not correct? Too much exhaust escaping? Thanks in advance guys.
-
Get rid of the 24" Laser II small hub prop and get a 23" tempest plus. A tempest wouldn't fit on the old small gear case and the gears were 2:0. That new case should be a 1:87 gear and you need a 23" prop now.
-
I have a tempest plus 24p on there now. So dropping one pitch should do the trick? I hear you only gain 200rpms per inch drop...?
-
Is this the same 24 that you had?
A tempest is a larger hub that wouldn't fit your small lower unit , you might have had a laser prop is what he is saying ,a smaller hub prop for the old lower units the laser 24 would be like a 22 tempest
-
You had a 24" laser II not a tempest on the old lower unit. A tempest wouldn't fit the small hub case.
Reply With Quote
