1970 johnson 60 hp overheating

keykev

Seaman
Joined
Aug 28, 2010
Messages
57
my 60 hp overheats under load . installed new oem pump kit,head gasket, 143 thermostat. water runs freely though powerhead with garden hose hooked to intake pipe,(lwr unit removed) cyl. head reaches 160 and exhaust cvr. 220.any ideas, thanks keykev.
 

jgriner

Petty Officer 2nd Class
Joined
Jul 22, 2010
Messages
146
Re: 1970 johnson 60 hp overheating

water pump installed correctly?
 

keykev

Seaman
Joined
Aug 28, 2010
Messages
57
Re: 1970 johnson 60 hp overheating

water pump installed correctly, i have had the lwr. unit off 3 times, i can do it 10 minutes now. new oem pump kit has smaller feed hole than oringinal. i have several outboards and have been doing pumps for years. maybe blown powerhead or exhaust cvr. gasket from overheating? this is also the only motor i ever had that has 2 pipes going into pump. one seems to be a return that is used until thermostat opens. i need to figure this out soon before my wife devorices me for working on my boat so much.
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: 1970 johnson 60 hp overheating

Couple of thoughts. The only thing that restricts water flow through the engine is the thermostat, remove the thermostat and run it and see what your temps are. You said that you have good flow with a hose attached to the water tube. Indicates a pump problem or water tube problem. The pump you installed has "a smaller feed hole", how did it fit the tube. Are both of the water tube grommets ok, not squeezed of from corrosion?
 

keykev

Seaman
Joined
Aug 28, 2010
Messages
57
Re: 1970 johnson 60 hp overheating

pump kit has new housing and grommets. i put housing on tubes with lwr. unit off to be sure it went far enough onto tubes to seal and it does,(i just got this motor and this could be why previous owner got rid of it) i did run motor with thermostat cvr. off and got water coming out but i dont' think with enough volume. i did try removing thermostat and it seemed to run even hotter. is there some kind of check vavle any where under powerhead that may have melted? i get a better flow of water (less restricted) though exhaust cvr. with garden hose connected to return pipe at pump. the problem definitely starts from to little water running behind cvr. thank you for the help, keykev......
 

keykev

Seaman
Joined
Aug 28, 2010
Messages
57
Re: 1970 johnson 60 hp overheating

i checked one more time and found water tubes out of round a little bit. i straighted them with a steel rod and problem solved. i quickly put my little gt150 in the water and went speeding around for about 10 minutes only to find smoke coming out of control box. motor wont shut off with key so i picked up a new blocking diode to replace one in box. i think i am getting there, thanks for all the help. kev.
 
Top