Throttle Lever Not Returning to Idle Screw

[WesleyV]

I have a 1978 Evinrude 70hp outboard motor. The motor started idling very high yesterday, but still went forward and reverse with a hard kick when put into gear. Brought it back in and noticed that the throttle lever won't return to the idle set screw unless manually pushed back. Once the lever is manually reset, it idles normal and shifts into forward and reverse easily. The problem pops up each time I speed up in forward and reverse then try to go back to idle. I disconnected the throttle cable, but the issue still remains, so I at least eliminated the cable. Any suggestions.
This is before I manually push the lever back:

Then after I push the lever back:

 

[interalian]

Probably just need to adjust the cable trunnion until the throttle arm will go back to the stop when you pull back to idle/neutral.

 

[WesleyV]

Just adjusted the trunnion nut fully inward and outward, lever does not fall back into idle without pushing it.
Also includes pushing forward and reverse on the remote control.

 

[interalian]

Is this a new problem or a new-to-you engine/boat? Cable may be worn. How much in/out play in the cable? Turning the trunnion nut so it's closer to the throttle arm should have removed that slop. Does the arm move freely?

 

[boobie]

How much play do you have in the throttle cable ??

 

[WesleyV]

interalian: I've had the boat for 2 weeks now. Had it on the water a handful of times without this issue. Then yesterday, it just suddenly idled really high after taking it back from full throttle. As for the arm moving freely, when pulled all the way back manually, it'll reset to the idle position easily. Pushed forward manually or with the throttle, it just seems to stick there.

boobie: Not a lot of play. But this cable has been in the boat for at least 12 years according to the previous owner.

 

[interalian]

I'd take the cable off the throttle arm and make sure there are no tight spots in its travel. Re-grease pivot points. Also, that vintage control cable may be setscrew type and they could be loose. Check cable at both ends to be sure.

 

[WesleyV]

So, if taking the throttle cable off, the arm still feels tight returning from fully open, what would you recommend?

 

[interalian]

Look for anything that binds. Pay attention to the timer base linkage that rotates the coil under the flywheel. Missing/damaged bushings? The arm should spring back from WOT but needs to be pushed back for idle.

 

[WesleyV]

I disconnected almost everything that connects to the throttle lever, throttle cable, shift cable,etc. The only thing that was still attached is the timer base. I'm thinking that maybe it needs to be cleaned and have a fresh layer of grease applied, if it's suppose to be greased. Does that make sense and sound like it could be the cause? Attached is a link to the video I shot that shows my motor's issue.

 

[interalian]

Timer base looks like it moves easily. Looks as though there's some room left on the throttle cable trunnion to shorten the distance between trunnion and throttle arm - that would pull the arm back when you pull back to neutral.

Did you check the cable for set screws?

 

[flyingscott]

It looks like your link and sync is off even when you back the timer base off it still looks like the cam is touching the carb. Also did you get any paint inside the timing linkage when it was repainted. Another thing is the trunion nut stripped on the cable which can cause all those problems.

 

[jimmbo]

The problem could be in the control box, as in a previously mentioned issue with the control cable, either not anchoured properly or inside slipping

 

[interalian]

It looks like your link and sync is off even when you back the timer base off it still looks like the cam is touching the carb. Also did you get any paint inside the timing linkage when it was repainted. Another thing is the trunion nut stripped on the cable which can cause all those problems.

All true. That's a lot of paint too.

 

[WesleyV]

Fixed. I finally understood what you meant, interalian, by set screw. So, where the trunnion is attached to the throttle lever inside the motor has a clip to hold it in place. What I thought was just a metal pivot screw for the clip actually has a hex screw in the center of it. I tightened it to grip onto the throttle cable and now it pushes and pulls like it use to. Thanks for all the input.

 

[interalian]

Cool. Glad you got it fixed.