Installing lower unit on 1980 115 HP Merc outboard

[imported_scott_r]

Having trouble installing a rebuilt lower unit on 1980 115 HP Mercury outboard. I have a 3/4" gap between lower unit and driveshaft housing and don't want to start forcing it. The prop shaft splines seem to be aligned, as I can turn the flywheel clockwise and the prop shaft turns. The water outlet tube is aligned into its guide sleeve. The shift shaft does not appear to be engaged yet, or at least the shaft on the lower unit doesn't turn if I move the shift control lever. Do you have to apply a lot of pressure to get the driveshaft fully inserted into it's coupler on the powerhead or am I missing something else? Suggestions and cautions?

 

[hkeiner]

Re: Installing lower unit on 1980 115 HP Merc outboard

I don't know if your particular motor has any special conditions but I found that on my motor, I have to be sure that there is no lube on the end of the shaft before inserting it into the female end in the housing. Excess lube can cause an "airlock" preventing the male end of the shaft from going into the female end.

"Airlock" may not be the correct term. Basically I mean that air is trapped inside the female end by the shaft because the excess lube keeps the air from escaping as the male shaft is inserted.

 

[imported_scott_r]

Re: Installing lower unit on 1980 115 HP Merc outboard

I don't know if your particular motor has any special conditions but I found that on my motor, I have to be sure that there is no lube on the end of the shaft before inserting it into the female end in the housing. Excess lube can cause an "airlock" preventing the male end of the shaft from going into the female end.

"Airlock" may not be the correct term. Basically I mean that air is trapped inside the female end by the shaft because the excess lube keeps the air from escaping as the male shaft is inserted.

Got it! Thanks for the reply.