Logo
FULL SITE MENU

1971 60hp losing power at full throttle

M

Matt86

New member
I recently acquired a 1971 60hp johnson. After installing it, we took it for a test run. It idled well, and ran great at full throttle for about 30 seconds and slowly started losing power. Suddenly it shut off. We checked the temperature to make sure it wasn't hot, and fired it back up. We took off, and it died again. We used the electric motor to get to our dive site, and after diving tried to fire the motor back up. Nothing, wouldn't even turn over. I pulled the cowl off, and noticed the fuse holder dangling there and not connected, so apparently that was causing it to die. It fired back up and we idled to the launch. Could the slow loss of power at full throttle have to do with the bad fuse connection, or should I look elsewhere? The carbs are spotless as I rebuilt them before ever firing it up, and all fuel lines/connections are tight. Thanks for any help!
 
Gotta have power through the fuse in order to start and run, so it certainly would affect it if loose or defective.
 
I got the fuse issue taken care of, and it still isn't running right. It will run great at all rpms for a while, then will suddenly start missing at full throttle. Once it starts missing, it runs rough through all rpms. The fuel system is definitely good, so I'm suspecting the power pack or coil. Any suggestions on something else that would cause this? Thanks
 
Remove flywheel.----Remove stator and distributor cap.-----Inspect anti-reverse spring.----Set breaker points to 0.010"----Clean rotor and distributor cap.
 
Thanks for the suggestions. I pulled the flywheel, and everything under there looks to be in good shape. I noticed some electrical tape on the amplifier wires, and pulled it off to see bare, corroded wires. The red wire on the rectifier was the same way. I'll be replacing the amplifier, rectifier, and coil tomorrow night, and hopefully be able to take it for a spin Saturday. If it's still acting up I will try the cylinder drop test.
 
Are you using QL77JC4 spark plugs? You should. If it still has the original surface-gap plugs, dump them into the deepest hole in the ocean, and put up a no-fishing sign.
 
Back
Top