I have a Sporty of a 98 300 ProMax with the 2 piece drive shaft and small prop shaft. I also have a blown up 2007 Sporty of a 07 250xs with the fat shaft. My question is will the fat shaft fit in the 98 ProMax case, if so what other parts will be needed. I would like to upgrade to the fat shaft. I don't have engine serial no's as I just have the lower units.
Yes they both are 3 liter motor 's. The drive shaft (both should have the same splines ) bolt and go .
Reverse gear is DIFFERENT between the two propshafts (as are carriers). You can swap ALL components, but should not intermix (exception- one piece driveshaft can be fitted to any that have two tapered roller bearings on the driveshaft).
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Thanks, all gears are toast as well as the driveshaft. I am looking to put the carrier and prop shaft in the 98 as everything in it is good.Originally Posted by EuropeanAM
Been trying to get the pinion nut off with no success. What size nut/wrench does it take, looks to be 7/8"
it is a 7/8, merc makes spec tool for removing pinion nut holds the nut while you turn drive shaft
.................................................. ...the scariest thing in life is the unknown ...................................
Thanks, unfortunately the shaft is broke at the bottom of taper about 1/8" inside the gear. Just trying to get the prop shaft out of LU and pinion is in the way.
I had this same problem. My tech had to put the holding tool on the nut and hit on a pinion gear tooth with a brass punch and hammer. I think you said earlier all gears were toast so you should have no worries. In my case all gears were good and we were trying to save them hence the brass punch. It appeared we were successful however 8 months later a pinion tooth flung out the side and destroyed everything.
You'll have to cut/split the nut from the pinion. Can be a real "bear".
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Finally got the prop shaft out, my son ended up moving the shaft while shaking the case and the pinion gear fell out. This was after I tried splitting with a chisel, using a large drift punch, a air hammer with a chisel and punch ends and grinding a couple of teeth. When the gear came out the nut was friction welded to the gear and spline on drive shaft piece. Prop shaft is good with no run out.
Does anyone know what the thread size is for the drive shaft bearing retainer nut, the threads could use a little cleaning up with a chaser.
Thanks to all for the help.
I guess I'll get my taps or pitch gauge out and check the threads on to retainer nut.
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