91' Mercruiser 3.0 timing

[ProSolo]

Good afternoon,

I have several questions.
I have EST and am confused about manual specs for timing.

As per manual - Initial timing should be around 1° and then:

With timing light still connected, start the engine and run at IDLE.
Verify that timing did advance to :

• If initial timing is 1° BTDC: 12° BTDC, plus or minus 2°. At 2400-2800 rpm maximum
(total) advance is obtained and should be 23° BTDC (plus or minus 2°).

• If initial timing is 1° ATDC: 14° BTDC, plus or minus 2°. At 2400-2800 rpm maximum
(total) advance is obtained and should be 25° BTDC (plus or minus 2°).

• If initial timing is 2° ATDC: 15° BTDC, plus or minus 2°. At 2400-2800 rpm maximum
(total) advance is obtained and should be 26° BTDC (plus or minus 2°).

1. How do I get a reading of more than 12° as timing tab and mark on damper are only showing up to 12°
2. Manual states 1° and then advances values but on I have plastic cap on my engine and timing BTC shows 8° (pics: https://ibb.co/yV1SPTP)

Thanks in advance!

 

[ProSolo]

Not sure if post I made is not understandable or no one can't help

 

[BillK2632]

I don't have any experience with EST ignition systems. BUT, to answer your question about getting above 12deg advance, you need a timing light that let's you set the advance. That way you just set the advance on the timing light and then time the engine to the 0deg mark on the crank.

 

[Scott215]

It's called a digital dial back or total timing light

 

[techmitch]

It's called a digital dial back or total timing light

"Digital advance"
I've had this one since the 80's.
https://www.ebay.com/itm/1554694294...VtYeehP-acLB6VW9G8mwHzT3SxlSG_DAaAkc5EALw_wcB

Here is the latest and greatest.
https://shop.snapon.com/product/Timing-Lights/Digital-Tach-Advance-Timing-Light/EETL500

 

[BillK2632]

After some thinking on this, it seems like those instructions are just a complicated way of saying what the base timing should be and what the advance should be. I would call EST to verify what the timing should be with their ignition on that engine - then if you don't have a light with advance just set the base timing to what they say. Concern with having the timing off (other than it might not run right) is detonation (pinging), that's bad and will cause damage to the engine in short order.

 

[techmitch]

That engine cover list a point gap and dwell spec.
That doesn't seem correct for a 1991?

 

[Scott215]

Thought they were electronic ignition back then I could be wrong

 

[Scott215]

Need to see the distributor with the cap off

 

[ProSolo]

Thanks a lot for your consideration and help!

I may be wrong saying only EST, I went by manual. Rather, it's Delco EST as what I have in the boat.
Only thing is I don't remember seeing those white cables (to be jumped) or I have just missed them.

If I go to the timing section for Delco EST I see this:

Manual is showing 1* but I am still confused by 8* showed on engine cover - perhaps it's wrong cap?

 

[BillK2632]

Ok, so this makes sense now - basically same procedure as the Thunderbolt IV, V. Jumping the white leads together puts the system in base timing mode (ie no advance is being applied), once in base timing mode, just set the timing to 1deg BTDC, you don't need anything special, just an old fashion timing light. Once you disconnect the jumper, the timing should advance to 12deg at idle and 27deg at 2400-2800rpm. Looks like the EST system is looking for 12deg timing where the old Thunderbolt wanted 8deg. Call them if you want to be sure (it can't hurt), but that's the way I read this.

 

[Scott215]

That's interesting I think he should be pretty much set with the total timing of 27 it's really not that much