'87 Merc 115, idles to fast.

[TylerH]

Installed new powerhead, and rebuilt carbs last summer. Engine has always idled a bit high 1300 rpms (neutral) 1000 (gear). <br /><br />I've retimed it and adjusted the idle stop, but lowest idle I've been able to get is around 1300. <br /><br />Would improper jetting cause a high idle?<br /><br />Aside from the high idle and clunky shift motor runs great. No bogging or symptoms of that nature.<br /><br />Thanks,<br />Tyler

 

[Laddies]

Re: '87 Merc 115, idles to fast.

Check the pick up and related linkage for binding or adjustment--Bob

 

[TylerH]

Re: '87 Merc 115, idles to fast.

Linkage between throttle cam and stator or linkage between carbs?<br /><br />Should also add, all 3 butterflys are completely closed.<br /><br />Been reading an airleak could cause this, but wouldn't that also have an affect on top end performance?

 

[Laddies]

Re: '87 Merc 115, idles to fast.

Carb syn & link

 

[Clams Canino]

Re: '87 Merc 115, idles to fast.

Ya.... seach this forum for my timing and sync post.<br /><br />-W

 

[TylerH]

Re: '87 Merc 115, idles to fast.

Evened out the linkage between the carbs and retimed the engine to 5 BTDC(Primary) and 18 BTDC(MAX).<br /><br />Have not adjusted the idle mixture yet, still getting dark pretty early here so I don't have much time to test.<br /><br />I noticed when I pulled the plug that they had some new nastyness on them that was not showing up last year or when I had the plugs out before starting it up after winter. Does engine fogger and fuel stabilizer typically leave a oily brown guck on the spark plugs when you fire it back up after sitting?

 

[Laddies]

Re: '87 Merc 115, idles to fast.

yep

 

[TylerH]

Re: '87 Merc 115, idles to fast.

Thanks for all the help. Got it idling at 650 - 750 in gear now. <br /><br />Anyone have detailed instructions for removing the autoblend system from this engine? smokes like it's nobody's business so i'm ready to make the swicth to premix.

 

[Laddies]

Re: '87 Merc 115, idles to fast.

Just bypass the unit with the fuel line and unplug the electical harness, then throw it in the junk I did mine when it was two years old, right after the second powerhead. Mercury did pay for both of then though--Bob