Carburetor choke not opening?

[ChronoFish]

Hi,
I have a 1989ish Mercruiser 3.0 with electric choke.

At idle the choke plate looks fully closed.



With the throttle at full (engine not running), it opens up just a touch (to where I think it should be at idle).




With ignition on and deadman switch installed the "purple" wire going to the heating coil is getting 12.5 v. Shouldn't I see the choke open up fully - or is that only when the engine has been running? What about at idle? Should that be at 1/16" gap? Or again, is that only when the engine is running?

what steps should I take? Bend the choke rod? Replace the heating element? Am I expecting the right things here?

Thanks!
CF

 

[alldodge]

The choke won't fully open until the throttle is opened a bit now and then. The idle stop screw rest against the cam. Open the throttle a slight bit and it should open further as the choke heats up

 

[Scott Danforth]

Worst case, it needs adjustment

 

[JimS123]

With a cold engine, the plate should be closed. As it warms up the plate should gradually open. When fully warmed up the plate should be wide open whether its at idle or WOT.

35 years with a 3.0 and the only work I ever did on the carb was to replace the choke spring. You should do that too, and then when the motor is fully warmed up, adjust the choke cover so the spring sets the plate wide open.

You "might" be able to adjust the existing choke, but with that old an engine its most likely worn out. Since its only pocket change, buy a new one.

 

[mr 88]

Not sure about the 3.0s but my 5.0 with a Rochester 4 barrel the manual calls for the choke plate to have a gap of 1/8 to 5/32 when cold. Can't remember the exact number but it did call for it to not be completely closed.

 

[mr 88]

Whatever the opening size was I used a drill bit of that number for the gap measurement to get the correct opening. So if it was 1/8 I grabbed that bit ,held it in the opening and adjusted the choke plate so it stopped there.