Need help timing 1986 mercury 90 inline 6 adi ignition

[drfeelgood87]

So I have a 1986 mercury 2stroke inline 6 with adi ignition" or without distributor". I've read the manual but am confused. In the manual it says once I set the pointer to .464 for TDC to hook a timing light up to #1 spark plug and adjust the idle screw to line up with the mark on the cam while cranking the power head. Then says to use a timing light for primary pickup and then max spark advance. The problem is if I align the marks on the cam and throttle and use timing light I'm at 2 degrees btdc. The cover says timing pickup is at 5-7 atdc. If I try to get to 5-7 atdc adjusting primary pickup screw. I'm damn out of screw. The same thing goes for max spark. It says to set at 20 btdc but I can't even reach that number adjusting the max spark screw. I'm confused on what I'm actually supposed to do. Do I use the idle stop screw to get my initial 5-7 or do I align the marks on cam and throttle and use the primary pickup screw to achieve 5-7 atdc?

 

[drfeelgood87]

Also the manual calls for primary pickup timing to be set at 4-6 btdc but my cover says 5-7 atdc. Max spark is the same on cover plate and in manual.

 

[Chris1956]

Your manual is wrong. Idle pickup timing of 4-6* BTDC is for the distributor ignition models.

Idle pickup timing for ADI ignition is 0-9*ATDC. Max spark advance is 21*BTDC, for both.

Remove prop, and spark plugs 2-6. Advance throttle until carbs are closed, but ready to open. Crank motor and set idle pickup timing.

Advance throttle fully, crank motor and set max spark advance.
Set throttle stop to allow carbs to open all the way, but not hit their stops.

Install all spark plugs and set idle stop to allow the motor to idle at about 850RPM. Adjust carbs in water, with warm engine in gear. You may need to reset idle stop.

 

[drfeelgood87]

Ok so the idle pickup timing is the small primary pickup screw to the left of the max spark screw correct?

 

[drfeelgood87]

So the only time I'm going to mess with the idle stop screw is to align the two marks on the throttle cam? And after I time the motor and set my idle in the water?

 

[Chris1956]

Different year motors and motor models had slightly different throttle arms. Your service manual should tell you what the various screws do, however, you should be able to see what they do as well. On my '93 V6, the primary pickup screw is just above the pivot of the throttle arm, to it's left.

 

[drfeelgood87]

On mine the idle stop screw is down bottom on the throttle arm. That's the screw you use to increase or decrease the idle or throttle. You use the idle stop screw to align the marks on the throttle cam like in the pic I posted. After I align the marks with the idle stop screw. I should be using the two screws side by side on the throttle cam to set the timing. One is small it's the primary pickup and the other is bigger and it's for setting max timing.

 

[drfeelgood87]

The manual has me screwed up cause of you read it. It says to use a timing light while cranking the power head and using the idle stop screw align the marks. So in other words it's stating 3 timing events not two. I don't understand what it means by that. Why do I have to use a timing light while lining the marks up. Doesn't make any sense

 

[Chris1956]

I had the distributor ignition IL6, so I am not real familiar with your timing procedure. I have a V6 ADI Merc now, so I have some familiarity with that timing process.

I would not worry about the idle stop timing marks and concentrate on setting the idle pickup and max spark advance specs using the timing light. If you then cannot get the idle speed where you want it, you can revisit it.

 

[drfeelgood87]

Ok... I got it timed right using the primary pickup screw and max timing. Carbs all the way open at wot and all the way closed at idle. Thanks. I'll post the results when I crank her up. Thanks for the help