3L cobra idling too high

[Wakelinj]

Hi all,

My 3L with cobra outdrive is shifting pretty hard. I shift with a firm, fast movement--no grinding. It's a pretty hard thunk into gear that you can feel, not just hear. Neutral idle is a touch above 700rpm. I've read 550-600 is ideal.

My idle stop is adjusted all the way out and it still sits there.

Is it safe to play with the mixture to try and bring it down? Do I need to rebuild the carb? Anything else that can cause this?

Thanks so much. I really cannot afford a new gear set!

 

[jimmbo]

700 in Neutral sounds okay the 550-600 spec would be in gear
That said, what does your Owners, or Service Manual say?
Messing with the Mixture Screws is not how you adjust the Idle Speed, except in some late 60s, early 70s Chrysler Cars/Trucks
On the Marine Carbs, Idle Mix can set by highest Idle Speed, but I prefer to use a Vacuum Gauge, adjusting for highest manifold Vacuum, in gear

Since you have been changing the Idle Speed Screw, perhaps the Cable Length needs a bit of Adjustment to ensure the Throttle Shaft is pressing against the Idle Stop slightly. That is referred to a Pre-load. None or too little can result in inconsistent Idle Speeds, too much and the Shift-Throttle Lever can be difficult to shift in and out of Gear

 

[Wakelinj]

700 in Neutral sounds okay the 550-600 spec would be in gear
That said, what does your Owners, or Service Manual say?
Messing with the Mixture Screws is not how you adjust the Idle Speed, except in some late 60s, early 70s Chrysler Cars/Trucks
On the Marine Carbs, Idle Mix can set by highest Idle Speed, but I prefer to use a Vacuum Gauge, adjusting for highest manifold Vacuum, in gear

Since you have been changing the Idle Speed Screw, perhaps the Cable Length needs a bit of Adjustment to ensure the Throttle Shaft is pressing against the Idle Stop slightly. That is referred to a Pre-load. None or too little can result in inconsistent Idle Speeds, too much and the Shift-Throttle Lever can be difficult to shift in and out of Gear

Thanks for the reply. A proper tuning of the carburetor is surely the right thing to do. But aside frim the mixture screw and idle stop there isnt really much that can be done to adjust speed, i gather. I was hoping to lean out the mixture a hair and get a small drop in RPM (like you can with a 2 stroke) but I guess that won't work. If the throttle cable is adjusted properly, the butterfly should be fully closed unless the idle stop is holding it open slightly, correct? So that should in theory be the lowest possible idle. Not sure if should play with the throttle cable adjustment. I would just love to get my neutral idle down 50-100 rpm for a safer shift.

 

[kenny nunez]

Try to post a picture of the throttle cable where it connects to the carburetor.

 

[Wakelinj]

Try to post a picture of the throttle cable where it connects to the carburetor.

Let me know if these shed any light on things. Tha ks for the reply

 

[kenny nunez]

Loosen the nut that anchors the cable and rotate the plastic nut threaded on the cable to lower the idle. You will have to also adjust the throttle stop screw to get the idle stabilized. Then retighten the anchor nut.

 

[Wakelinj]

Loosen the nut that anchors the cable and rotate the plastic nut threaded on the cable to lower the idle. You will have to also adjust the throttle stop screw to get the idle stabilized. Then retighten the anchor nut.

I'll do that. Thanks. Do I adjust the Idle stop so it's just touching the cam without moving it?