Short to Long Shaft swap on a 1995 20HP

[Scode68]

I have a 1995 20hp short shaft motor that I bought in 1997 but want to convert over to a Long shaft (20"). I'm running into issues on what parts I can use from what years from different marinas and parts people. For example I've been told the exhaust housing can be from 1985-2006, 1984-98 and others have said any year will fit. I know some time in 1994 the 20hp changed.

It is my understanding that I will need the exhaust housing, shift shaft, drive shaft and the water tube. I see these corresponding on your current parts catalog 9098A5-A7, 862933, 99198, 86292. Is this correct? Was looking at possible 25HP motors as a donor but I see the exhaust housing shows 9098T5 as the part number where I thought it was the same as a 20hp of the same vintage.

Mercury cant tell what the differances are beteen the 9098A5-A7 (20hp) and the 9098T5 (25hp) housings or if they would interchange. Could the T5 just have a interior coating for extra corosion resistance? Anyone have an idea or advice?

 

[racerone]

find-----bay manufacturing-----They may offer a kit.------Around $450 I think.

 

[Scode68]

If I can locate the kit then that would be great. The Mercury parts I can get for much less though if I can just get a straight answer from these guys with the parts motors.

 

[racerone]

The swapping of parts gets into fine details.------You might have to pull the powerhead to install the longer exhaust housing.----You might have to pull the gearcase apart to install a longer driveshaft and shift rod.

 

[flyingscott]

Buy a different motor or try to find a blown donor motor and swap powerheads. If you get lucky find a 25 hp and swap carbs onto yours.

 

[Scode68]

Buy a different motor or try to find a blown donor motor and swap powerheads. If you get lucky find a 25 hp and swap carbs onto yours.

Easier said than done since I haven't found any 20-25hp 1995 and up Merc engines for parts in my area. Lots of them salt free in the northern mid-west and Im in NJ.

If I can find out the differences between the drive shaft housings I would be in good shape.

 

[flyingscott]

Look at the base gaskets are they the same for 86 and up? Driveshaft splines the same?

 

[racerone]

One issue is that sometimes the castings are the same.-----Then on some model they use bigger bolts / locating dowel / bigger threaded holes.--- than previous model.---This part would then have a different part # but can be used.----You could easily modify these parts.-------A good shop ( if there is one in your area ) would help you.-----The big box dealers / stores will not help you.

 

[flyingscott]

post #7

 

[Scode68]

Look at the base gaskets are they the same for 86 and up? Driveshaft splines the same?

Between the 1995 20 & 25 all of the parts look the same except for the number on the drive shaft housing. I looked up adapter plate (base plate), gasket for housing to the plate, bolts, water tube, shift shaft, drive shaft, lower unit case and dowel pins.
The older engine shows the adapter plate, gasket and drive shaft housing as being different part numbers. Shift shaft comes up as 86293 where the newer engines have 682933 so I think that might be a typo in the Mercury catalog.

 

[flyingscott]

Good luck with your motor

 

[racerone]

Agreed.----Good luck.