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Getting off the lower unit of an Johnson Sailmaster 6hp from 1986

V

VJR

New member
Hey! I have to switch out the impeller on my Johnson Sailmaster 6 from 1986, but I am struggling with getting the lower unit off. I have removed the 2 bolts on the bottom and the long bolt at the front, passing through the extension and the lower unit. I have tried pulling very hard and managed to get the lower unit off by a small bit. I am unsure whether there is another piece that should be loosened or if I should just pull very hard (it was most likely ages since the lower unit was removed). Any tips or ideas on what to try would be helpful!
 
VJR said:
Are you sure there is no such coupling? I have not been able to find a coupling to disconnect but I'm afraid to just pull the whole thing apart
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I did some further research and in fact, found that there is no shift connector to disconnect. This engine is splined top and bottom of a one piece shift shaft. It has a 1/2 moon spline top and bottom. If you study the exploded views of the gearcase and midsection you can get a better understanding of how it works. I suspect you have the driveshaft spline going into the crankshaft in a bind due to lack of lubrication (grease) from poor maintenance practice. Try driving tapered wooden door shims at the gear case joint and tap them until the gearcase drops. The two bolts that you removed are the only thing that holds the gearcase in place so it should come off with some persuasion. Sorry for the confusion.
 
For a 1966 20 Hp Johnson I had the same problem after all shafts are disconnected (I had a shift shaft coupler it had to be disconnected) the lower case and exhaust case would not separate. Anyways it would not separate after all things disconnected. I succeeded only after spraying a lot of PB blaster down the exhaust casing to the power head, then poured some liquid wrench down there also. I had the motor tipped past 90 degrees when doing this. It stayed like that for 2 days and I had a wooden wedge rammed between the 2 cases. It took 2-3 days of tapping this wedge before it finally popped. Boy did I thank God for that one
 
VJR said:
Hey! I have to switch out the impeller on my Johnson Sailmaster 6 from 1986, but I am struggling with getting the lower unit off. I have removed the 2 bolts on the bottom and the long bolt at the front, passing through the extension and the lower unit. I have tried pulling very hard and managed to get the lower unit off by a small bit. I am unsure whether there is another piece that should be loosened or if I should just pull very hard (it was most likely ages since the lower unit was removed). Any tips or ideas on what to try would be helpful!
Click to expand...
I had difficulty with one of these ( actually a 1984 Evinrude Yachtwin) caused by corrosion of the drive shaft and a bush , through which it passes , in the 5" extension piece of the exhaust housing ,

Secret , if this is the cause , is the unbolt the extension from the exhaust housing (two bolts in addition to the long one at the front) and remove it with the gearcase.
Clean up the drive shaft then remove the extension.

When reassembling fit the extension to the exhaust housing first.

Most probably your trouble is due to the drive shaft splines being stuck in the crankshaft by corrosion . Always lightly grease the splines before re-assembly to prevent this happening
 
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