1975 115hp Merc

utfyrfytr

Petty Officer 2nd Class
Joined
Jul 14, 2014
Messages
195
How can I slow the idle on my 75 115hp merc? It idles at 1250-1300 RPM. I can give a little tug on the distributor and it will come down to about 900 but, the next time I rev it up it will stay at 1250 again. Is the idle adjustment part of the link and sync process, which I know nothing about? one other question, when it hasn't been started for a week or so you have to crank on the starter for 30-45 seconds at least before it will start. It seems longer but I have never actually timed it. After that it starts right up. The only thing I know to compare it to is my old 67 100hp merc which would start almost immediately cold or hot. I guess my question is, is taking that long to start common or indicative of another problem? Thanks for your help.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,688
You need to release the throttle cable adjustment barrel/nut from it retainer. Then you can adjust the idle speed/stop screw while holding the throttle linkage arm on the port side against it. Once the speed is set for an in gear under load rpm of 600 - 650, you then need to adjust the forementioned adjustment barrel so there is a bit of preload against the throttle screw stop.

Can't find a link for the idle speed screw/stop, it should be one of the screws on the distributor

Here's some info about the cable adjsutment
http://www.boatinfo.no/lib/mercury/manuals/mercury_1965-1989_40-115.html#/334
 
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