1987 evinrude 175 throttle problem.

[pmoxsib16]

Hello my name is Paul I am having a problem with my 1987 evinrude 175 outboard. The throttle lever attached to the side of the motor does not seem to be returning all the way and it is causing a high idle...close to 1500 rpm. I can push back on it with my hand butterflies on the carbs close all the way and the idle drops back down closer to 1000 rpm...I'm not sure what is causing this...all the throttle return springs are there on the carbs rhemselves...does anyone know if there is another spring that is supposed to return the lever to its home position after moving the throttle back to neutral?

 

[emdsapmgr]

Once the carb butterflys are closed completely-the idle/air mixture is set perfectly. The actual rpm is set by adjusting the idle timing. There is no spec. for the exact idle timing, as it is dependent on how deep in the water the engine is on the transom. So each engine is different-depending on the boat. To reduce the idle rpm, reduce the idle timing. See your factory service manual. FYI, the idle on that engine is set only when the boat is floating normally in the lake and the engine is shifted into forward gear. Can't set it on the trailer. Set the timing so the rpm's are between 650-750 rpm's.

 

[pmoxsib16]

I see what you're saying but my problem is I have to force the carbs to close all the way by hand...the lever that opens and shuts all 3 carbs is not returning all the way so it's holding the carbs slightly open

 

[Fed]

This may help you.

 

[emdsapmgr]

Best to do any carb butterfly adjustments with the throttle cable disconnected at the engine end. Sometimes that cable is not adjusted properly and will bind, holding the carbs ajar. Make all adjustments with the throttle cable disconnected. Once you have it idling correctly with the cable disconnected, then re-fit the throttle cable end to match the pin on the linkage. Many time slight adjustment to the trunion nut may be required.

 

[pmoxsib16]

I'm thinking this is what's happening...something is holding the butterflies slightly open at idle I will start with the cable...if not I believe there is a spring inside that lever assembly I wonder if that spring is worn

 

[emdsapmgr]

The spring should assist in returning the throttle to the idle position-unless the throttle cable is mis-adjusted and won't let it return to the correct idle position.

 

[pmoxsib16]

Exactly so I'm gonna follow your instructions and try to properly adjust the cable