1977 70 hp evinrude REAL high idle at start, then mellows out

[dragula]

Model number 70S77 ( i think) takes a couple tries to start up, but when it does it sounds like the flywheel is gonna blast off into outer space. Very high rpm at start then it mellows out.

im Hoping for some guidance. I am gonna start with a carb clean. Then adjust the slow speed orfices...at the top of the carbs? Is there anything I should inspect? The fuel pump is probably bad but it doesn’t stall.

 

[racerone]

Sorry-----The parts book does not show adjustment for the low speed orifice.-------It is installed tight and the plug screw is put in.-----NOT ADJUSTABLE !

 

[dragula]

Ok. I can’t find any fuel/air mixture screws on the carbs or intake manifold...I will mess with the throttle linkage and see if the valves are stuck in a position At start up. Is there an Idle speed screw?

 

[flyingscott]

Pull the airbox and make sure all the butterfies are fully closed.

 

[dragula]

flyingscott I was running it with the airbox off honestly. I have to manually close the front butterfly valves half the time.

Is it advisable to stick a paper clip or some fishing wire into the slow speed orifice to clean it?

 

[flyingscott]

The front butterflies are the choke. What about the back ones that are actually the throttle butterflies.

 

[dragula]

Not sure. I will have to check those out on Friday when I give it another go.