First find your year model and aquire a impeller kit as it will have all the replacment parts needed. To change the impeller you need to remove the lower unit. Put the motor into forward gear and remove the bolts/nuts holding the lower unit to midsection. Note that there is usually one bolt under the trim tab, usually it a total of 6 mounting bolts/nuts or less depending on year model. Once bolts/nuts are removed, the lower unit will drop down. The pump housing will be right on the top of unit with drive shaft protruding thru it. The pump housing is removed, then the impeller can be removed from the shaft. Retain the flat key and reinstall it with the new impeller,gaskets and wear plate. Lube the housing with some petroluem jelly or white grease, while pushing housing down turn driveshaft clockwise to seat the impeller in housing then torque nuts to 100 inch pounds. Reassembly is the reverse but make sure you line up the shift splines.
The dry weight of a 1983 model, 40hp Mercury outboard, is 156lbs.
It really depends on usage, but a good rule of thumb is once yearly.
0d161839
50:1
I would say one per spark plug.
The plug gap for a 1995 model, 40 hp Mercury is .035 in.
Need to know if its 2 or 4 cycle.
A 40 hp Mercury outboard, serial number 5897057, would have been manufactured in late 1981.
I have a 1996 Mercury 4 cylinder 40hp with 125 Psi across all 4 cylinders. I also have a mid 80s Mariner/ Yamaha 40hp 2 cylinder with 123 Psi both cylinders. I'm not sure what factory specs are, but maybe this would help.
The dry weight of the Mercury outboard FourStroke 40 HP boat motor released in 2005 is approximately 250 pounds. Later versions of this motor are slightly lighter.
The dry weight of a 1992 40hp Johnson is between 180 and 190lbs. depending on the model.
An Oil Injected motor will have a separate Oil Resevoir, so mixing Oil and Gas is not required, and in fact inadvisable.