2005 mercury xr6 idling problem

[Tx 1]

My first post. I have a 2005 mercury xr6 s/n 1B042693. Had this engine for 8 years and know the original owner well. Been maintained and well taken care of. Great running engine throughout power range but it’s always been a dog in neutral idle and in gear idle. Recently rebuilt fuel pump, replaced fuel filter, new primer bulb, new fuel line from tank to engine and installed Chris Carson reeds. I played around with idle mixture screws to keep it from dieing at idle but engine shakes and vibrates rough. Neutral idle bounces around between 500-650 rpms. Once I give it throttle it purrs … checked timing per the service manual and is spot on. Compression is 90-95 on all cylinders cold. Any tips would be greatly appreciated.

[JOE54]

personally i think they're idle specs are to low i to have seen these mtrs exhibit this condition , try in gear 650 not on a hose in lake water

[TMANN]

I have a 04 200hp motor that literally took me 6 months to figure out. Should be the same WMV carbs. Here's where I'd tell you to start if the carbs are clean, proper link/sync is done, and you've made sure the fuel delivery to the carbs is good. Lines, pump, tank vent, etc. The factory setting for my carbs are 1 1/4 turns out, I believe off memory yours will be 1 1/2 out. I have mine set to 1 1/2 out and I removed the backdraft jets to correct a mid range bog. Keep in mind, that idle rpm is controlled by inital timing. I'd start with your idle screws out 1 3/4, then set the timing where your idle rpm on muffs in the driveway not in gear @ 800 or so. It will idle lower in the water, proboly 625 or so in gear. I'd guess that timing setting will be around 4*. Obtain a factory service manual if you don't already.

[Tx 1]

Re did the link and sink and set idle mixture screws to about 1-1/4 out . Advanced timing was off a few degrees from what manual says. Runs and idles great now!

[JOE54]

[EuropeanAM]

You will find these engines like to have the idle air mixture screws opened up about 1/8 - 1/4 turn from their original/factory settings. This is primarily due to differences in burn-rate of the "fuel" (term used VERY loosely) we get today.