Hey guys I have a 96 40hp mercury outboard that I picked up for my jon boat and the throttle won't return to the idle position even with the linkage disconnected. Here's what I got, is it supposed to have a return spring?
There is a spring behind that round throttle arm with the bolt going through it, but that might just be the timing advance return spring. Take a look at #24 in the linkage parts in this link:
I'm not sure if that's your motor exactly, you can put the serial number in on the website to get the correct layout for your specific motor. But usually the throttle cable is what returns the linkage back to idle. From what I remember, the carbs each have a throttle return spring in them to help them close when throttle is not being applied.
My boat is wrapped up for the winter but it's a 94 Merc 60/45 jet 3 cyl and yours looks like a 4 cyl so the linkage is different.