1980 johnson 25hp

TinBoats.net

Help Support TinBoats.net:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Riverbean

Well-known member
Joined
Aug 9, 2020
Messages
100
Reaction score
0
Does anyone know why theres 4 holes here? I cant find no schematics with 4 only 2...1005200929a.jpg
 
L to R

Choke, stop, start and power.

That is if it is electric start.

One could also have been added for a modern type kill lanyard switch.
 
Ok....yes electric start..there was no grommet for the power hole next to the choke and no battery cables hooked to starter so that makes sense....i have a seized motor( in the pic) that im gonna do a total rebuild on and am curious why the inside of the powerhead is red and and the inside of the crank is yhis goldish color...1026201210a.jpgView attachment 4View attachment 41026201224.jpg1026201224b.jpgView attachment 1
 

Attachments

  • 0816201321.jpg
    0816201321.jpg
    4.3 MB · Views: 260
  • 0816201322.jpg
    0816201322.jpg
    4 MB · Views: 260
RaisedByWolves said:
L to R

Choke, stop, start and power.

That is if it is electric start.

One could also have been added for a modern type kill lanyard switch.

When i got it, it was L to R choke, empty, start then stop.
 
Not staing from the fuel, theres no red under that...i assume they dip the powerhead minus the covers cuz the outside of the powerheads red under the white paint, i can see where the paint couldnt reach because they paint the motors when assembled....also pulling off the manifold and polishing the inside wont hurt anything will it?1012202023.jpg1029201428.jpg
Also what about filing the edge at the bottom here leftover from when they cast it??
 
What do the water deflectors do in the jacket around the cylinders? Looks like they would block water from going all the way around them..??
 
Polishing the manifold wont hurt, but it wont gain you anything either.

Going to a 35hp carb and intake will get you some added power though.

No cleaning off the flash wont hurt and might help but the effects may be negligible.

The deflectors IMO are there to prevent uneven cooling of the head. They kind of puzzled me at first, but they must be there for a reason and thats all I could come up with.

Most likely having something to do with obtaining a good idle.
 
And the intakes are the same on the 25 and 35, carbs r different as to HS orfice and venturi or throat ID or size...#386792 manifold on both motors..
 
Riverbean said:
RaisedByWolves said:
Riverbean said:
25 and 35 intakes are the same...already has the 35 carb on it.

Nope, you have the small intake.

Post above👆

Ok, but can you explain to us why my known 80 35hp intake looks so much different than your supposed 35?


IMG_0724[1].JPG


That is a 35hp intake with a 70hp carb for a motor Im building.



Here is your pic of your intake. There is a massive difference in the volume between the two with the 35 unshrouding the entirety of the reeds, where as the 25hp intake blocks about 25-30%. of the usable reed face.


25hpintake.jpg





If you wont listen or dont want to learn, fine, but your pic is of a 25hp intake!

As Pappy likes to say, we prefer the truth on this board and while it may seem a niggling thing, I would hate for someone some time in the future to come along and get bad information and further spread it based on someone's confusion of the facts.

IIRC there are several sources for this information, but at this point I question whether youll seek out the knowledge or not.
 
Look up j25rcsa and j35rcsm or any other 25 or 35 from 1980 they both have intake part# 386792...has nothing to do with wanting or not wanting to learn..i know excatly what i have and i know im right aboit the intakes...look em up....id say yours is not off an 1980 35 if the part # stamped on it does not match above number i showed...
 
I originally got my info off here from a guy named johnnyrude...either way its right...
 

Latest posts

Top