1967 80 hp evinrude speedifour loses power

[chris29]

Hi all i have a 1967 evinrude 80 hp speedifour motor . the motor idles fine but when you excellerate the throttle it bearly pics up at all and stalls. but will restart and run at idle. any ideas ? thanks

 

[Chris1956]

Re: 1967 80 hp evinrude speedifour loses power

Check compression and spark on all cylinders. Those motors will run pretty well on 2, do you know if it is idleing on 4 cylinders? What do the spark plugs look like?

 

[BonairII]

Re: 1967 80 hp evinrude speedifour loses power

Yup...they do run pretty well on 2 cyls (i have own the Johnson version of your motor). Mist the cylinders to see if the motor picks up, if not You probably have an ignition issue.

Have you done the sync-n-link per the manual? Check/replace points and condenser.

With the cowling off(not running), go to full throttle and check to make sure the "safety stop"( i forget it's real name) is not preventing the distributor from fully rotating to the full advance position. My shift linkage was not adjusted properly and my 'stop' wasn't fully getting out of the way of the distributor.
It caused me 'fits' until I finally noticed it.

 

[chris29]

Re: 1967 80 hp evinrude speedifour loses power

Check compression and spark on all cylinders. Those motors will run pretty well on 2, do you know if it is idleing on 4 cylinders? What do the spark plugs look like?

i pulled the plugs out and they looked new as the previous owner had stated, but on 1 plug the threads on the spark plug looked wet but the electrode was not.i was told the boat had been sitting for the past 5 years. at idle i didnt notice even a miss. i havent checked compression yet i dont have a compression gauge. it seamed as though that as the motor come up to operating temp was when the power loss was noticed most. thank you for your help.

 

[Evinrude Boater]

Re: 1967 80 hp evinrude speedifour loses power

If it's been sitting for 5 years then there's a good chance the carb is gummed up preventing proper fuel flow when you accelerate. Choke it when you take off and see if that helps. That's a good sign the carb is plugged. It's a good place to start with a motor that hasn't run for a while.