Adjusting idle mixture on 115 Merc

[fishaholic911]

I have a 1986 mercury 115 inline 6 that I can't seem to get the idle mixture set just right on. I started my adjustments with the screws turned 1 1/4 turns out from a light seated position. As I started screwing them out farther it seems to do a little better. I am currently at 2 turns out and it still accelerates a little rough when i first throttle it up. My question is can I continue to adjust the carbs richer to obtain a smooth take off or is anything over 2 turns to rich and unsafe for my motor.

 

[timmathis]

Re: Adjusting idle mixture on 115 Merc

I would try it in 1/4 turns out untill it clears up or starts to fall off any. I'm not sure on the max turns out!!.<br /> Have you ever had the carb's off for a cleaning?

 

[Laddies]

Re: Adjusting idle mixture on 115 Merc

You can't get the idle mix to rich if the engine will still idle however it is a indication of a dirty idle passage or low float level

 

[fishaholic911]

Re: Adjusting idle mixture on 115 Merc

yes i have cleaned the carbs recently. I just didn't know if there was a max on how many turns out i could go. most of the local mechanics tell me that 1 1/2 to 1 3/4 turns is the norm but no one can tell me how many turns is to far.

 

[fishaholic911]

Re: Adjusting idle mixture on 115 Merc

I recently rebuilt the carbs so I may not have my floats adjusted just right. I did though adjust them according to my clymer manual that I have on my motor.

 

[Clams Canino]

Re: Adjusting idle mixture on 115 Merc

1'd say over 2.5 out indicates something strange for sure. <br /><br />-W

 

[fishaholic911]

Re: Adjusting idle mixture on 115 Merc

Ok It now seems to be doing good at 1 3/4 turns but now when I first launch my boat and go straight to full throttle it doesn't throttle up very smooth. after reaching wot at about 5500 rpms I can go back to idle for any amount of time and then go to full throttle and it is smooth as silk. It only does this when I first launch the boat or if while on the water the motor is left off for a pretty good while. I thought my floats might be set too high. what do you guys think.

 

[timmathis]

Re: Adjusting idle mixture on 115 Merc

Did you do a link & sync? If not it may help some.<br />My 1975 150 H.P. does the same when cold after it warms up it does o.k. ??? Tim

 

[Clams Canino]

Re: Adjusting idle mixture on 115 Merc

I think it's cold. Warm it up a minute at 1500-1900 rpm before punching it. I turn them in slowly till it starts to die then out 1/2 to 3/4 from that spot.<br /><br />-W

 

[fishaholic911]

Re: Adjusting idle mixture on 115 Merc

Ok, I read the post that clams put up about how to time and sync a motor and i did all of that including trying to warm the engine up and my motor still takes off rough at the begining. I did though learn something that I didn't know from clams post that may shed a little more light on my situation. I notice that he said that the idle speed out of gear idealy needs to be below 1000 rpm. Well I have to keep my engine set at 1000 to 1100 so that when it is in gear it will still idle. It dies as soon as I shift it into gear if it is set at anything below 1000. Having said that I am now wondering if bad reeds may be the reason I can't get this motor running just right. Also if you guys think I am being over paranoid here please tell me, because I do tend to let little things like this bug the crap out of me. after all my engine does run ok except for this little flaw. thanks.

 

[Clams Canino]

Re: Adjusting idle mixture on 115 Merc

It could well be tired reeds/reedblocks. Usually I disconnect the idle stabilizer forever. YOU may wanna use it as a band aid. Do the 1st round with it's blk/wht wire disconnected - then hook the wire back up and drop the idle back to where you wanted it. Then double check max-advance for 21 at cranking again to be safe.<br /><br />-W

 

[MercFan]

Re: Adjusting idle mixture on 115 Merc

Clams... Can you go into a little more detail on the idle stablizer?<br /><br />I got black, white and something on the distributor side (I know it's 3 wires) of the ignition module, and a red, white, black and brown (I think, I know it's 4 wires), on the starter motor side.<br /><br />Which wires make up the idle stabiliser?

 

[erniex]

Re: Adjusting idle mixture on 115 Merc

Are you sure this is a 1986 motor? Sounds much older with the distributor and single power pack-my 1973 is set up like this without an idle stabilizer - what's the serial number?

 

[Clams Canino]

Re: Adjusting idle mixture on 115 Merc

Mercfan yours is older than Fishaholics, it don't have one at all. <br /><br />And Ernie... Mercfan is not the original poster.<br />Try to keep up. <br /><br />-W

 

[MercFan]

Re: Adjusting idle mixture on 115 Merc

Yeh Erniex,<br /><br />My motor is an early 70s. Just wanted to know if it has the idle stabilization aswell?

 

[MercFan]

Re: Adjusting idle mixture on 115 Merc

Originally posted by Clams Canino:<br /> Mercfan yours is older than Fishaholics, it don't have one at all. <br /><br />And Ernie... Mercfan is not the original poster.<br />Try to keep up. <br /><br />-W

Thanx a mil Clams <br />One less thing to worry about

 

[erniex]

Re: Adjusting idle mixture on 115 Merc

Sorry W- guess it just moves too fast for me