73 850 high idle

[Jdevon_14]

I got a 73 mercury 850 that I took off the carbs to clean over winter. Put it all back together the other day started it up and it was idled way to high. I adjusted the throttle cable as far as the distributor would let me and it idled down a little bit. But it's definitely still too high. Just curious to where I go from here?

 

[Texasmark]

Apparently your clean up was needed...engine running better than it did before. Move the throttle linkage and watch the vertical throttle arm that moves on the engine. When you bring the remote back to idle position, there should be a knurled, spring loaded screw that limits how far that throttle arm can move. I'd back that off and it should solve your problem.

 

[Jdevon_14]

It sure was previous owner didnt maintain it very well. I think I know what you're talking about I'll have a look when I get home. Thank you

 

[Chris1956]

You may have changed the idle pickup timing when you worked the carbs. You need to check link and synch.

I would recommend a OEM service manual as the link and synch is involved. Make sure it has your motor in it, as the ignition system changed significantly in 1975.

 

[Jdevon_14]

I checked the service manual I have and couldn't find any info on syncing the carbs. You're not the first person to suggest this so I'm going to keep looking

 

[1960 Starflite]

I have a 1975 850. Installed it on my Pontoon. The idle also was way too high. I found the timing was advanced too far at idle. I believe the idle RPM is controlled by the timing, not a stop screw. Yep, link and sink :facepalm:

 

[racerone]

The STOP SCREW controls idle speed on the arm that is hooked up to timing !

 

[Chris1956]

The brass collar on the midsection of the distributor adjusts the "fingers" that open the carb throttle plates. The carbs should be ready to open when the timing is 4-6* BTDC. Max spark advance is 21* BTDC.

The throttle stop stops the throttle at full carb opening. The idle stop screw plus the throttle cable adjustment sets the idle speed.

A service manual is a real good idea.