4hp johnson

[Date]

hi i have a 4hp Johnson 50th anniversary i was wondering what year that would be also is there anyway to get a book that shows how to put it together

 

[Joe Reeves]

Re: 4hp johnson

There should be a plate on the port (left) transom bracket (bracket that attaches the engine to a boat). That plate would have the model and serial number imprinted upon it.

What is the model number"

 

[Date]

Re: 4hp johnson

model # 4w72s Serial # e3538875

 

[Xcusme]

Re: 4hp johnson

Date, Welcome to iboats!


That should be a 1972 4hp Johnson.

 

[Date]

Re: 4hp johnson

what is the gas to oil ratio and with the rewind starter i have it coiled tightly and all assembled but when i pull the chord it doesn't fully rewind is there a special point on the attached diagram that the notch on 10 must go in the cup & stop

 

[lark2004]

Re: 4hp johnson

you can run these motors at 50:1 ....but, they still have bronze bearing in them.

I prefer to run mine at 40:1 (32:1 is even better) if they have these bearings.

I have just finished pulling a 75 model 4hp evinrude down, that has been run at 50:1, and there is alot of evidence of heating around the rod ends, and some scoring on the crank in the middle bearing area that seperates the top and bottom crankcase chambers.

On a 63 3hp that I am restoring, (same crank and rods) that has been run at 24:1 all it's life, the crank is in perfect condition, and there is no sign of heating around the rod ends at all.

the crank on the left is from the 3hp, the right from the 4hp..... you can see the discoloration around the rod ends on the 4hp crank and scoring on the middle bearing surface. (n.b. ignore the pistons, they have yet to be cleaned up)