85 HP Mercury Outboard Thunderbolt Ignition

I have an 1975 85 HP Mercury Outboard Thunderbolt Ignition. When starting the boat, I fully open up the warm up lever. The boat turns over and only idles between 800 - 1000rpm (roughly). I removed the hood and noticed that the distributor wasn't roating all the way. I pulled it (choke lever) and she went like crazy (approx 2500 rpm). However when I lowered the lever, it droped down to around 1000rpm and was running very rough again. I changed the plugs, wires and gas. I also tried adjusting the screw and it kind of helped for the ideling. However when I went to open it up again, (the lever) it's not engaging/pulling all the way. Only goes up a couple of hundred rpm and I have to manually pull on the choke lever to get it going. Any suggestions of how to fix this problem.

Re: 85 HP Mercury Outboard Thunderbolt Ignition

First that not a choke connected to the dist. it's spark advance lever, don't tinker with any of the screws on it except the idle speed screw when the engine is shifted into gear the throttle is advanced by pushing the shift lever further ahead not with the fast idle lever, that you are calling a choke lever. It also sounds like the idle mix needs adjusting and I wonder if you want to undertake the project.

Re: 85 HP Mercury Outboard Thunderbolt Ignition

You say that the idle mix needs adjusting. Is this a difficult project?