Mercruiser 3.0 block Identification

[Boatdad20]

Hello all I just recently put in a new reman 3.0 engine and I’m trying to set the timing right I can find the right place to look up the block I’d code there are no mercruiser tags on the new motor and the new engin is definitely newer it has a sensor on the lower port side and has holes for fuel injection on the head I have attached a pos of the block serial number

 

[alldodge]

That's a block casing number

What was the year of the original motor and is this motor the same as the original?

 

[Boatdad20]

The original is a 94 and the new motor is newer it has a sensor down low and infliction Ports in the head I did read that the timing go to 1 ATDC and 2 ATDC and I just want to make sure I have it set right is there a way to determine what year the long block is ?

 

[alldodge]

Wish I had an answer for you, but not knowing how the motor was built, I don't know.

Advancing timing means as it advances, timing gets further BTDC. As example using 13 degrees adavnce

1 BTDC = 13 BTDC at WOT
1 ATDC = 12 BTDC
2 ATDC = 11 BTDC

So with less timing there is less advance. The good thing is less advance also means less chance of ignition knock.

Hey Scott Danforth have any thoughts?

 

[Scott Danforth]

If the block has a 1-piece RMS, its 1991 or newer.

There were some EFI 3.0 motors. Not sure what is different on them. I thought the injectors were in the intake on them

 

[achris]

If the block has a 1-piece RMS, its 1991 or newer.

There were some EFI 3.0 motors. Not sure what is different on them. I thought the injectors were in the intake on them

They are. Same head, carbed or injected. Been the same head since 1990...

 

[achris]

The original was 1994 and the new motor is newer. It has a sensor down low and injection ports in the head. I did read that the timing go to 1 ATDC and 2 ATDC and I just want to make sure I have it set right. Is there a way to determine what year the long block is?

Added a few stops to make your post readable...

If you put the same manifold and carb back on the new engine, everything will be the same as the old engine. The head is the same since 1990, no injector ports in the head.

What ignition system is on the engine? (points, DDIS, EST) That is what will ultimately determine what the timing should be.
And if you have the serial number from the old engine, that would be very helpful. (should be on the flame arrestor on the carb). And if you can give us the number off the carb, that would also be helpful. Should be one of the following numbers.
1389-9562
1389-815396
3310-806077
3310-806078
3310-805924
3310-815397

Chris.......

 

[Boatdad20]

Hear are photos of the head there different than the old engine as added a picture of my cover also tomarrow I will look at the carb where exactly are the numbers located

 

[Boatdad20]

And I do know it’s an est ignition

 

[achris]

Here's the timing spec, and the correct way to set it...

 

[Boatdad20]

Ok thank you for the info and also idle it 700rpm in gear ?

 

[achris]

Ok thank you for the info and also idle it 700rpm in gear ?

650-700 rpm in forward gear. What I usually do is set the idle at 650-700, set the timing and idle mixture, then set the idle speed to 700-725 in neutral. That brings it down into the 650-700 range when the boat's in the water and in gear.

Chris......

 

[Boatdad20]

Thanks for the info I have another question I just replaced the ignition control module, pick up coil , ignition coil ,spark plugs and new cap and rotor it runs a lot better at lower idle but I’m still reading 1 degree BTDC till I reach 850 rpms then my timing will advance to 11 degrees BTDC at 1100 rpms then at around 2400 rpms I’m at 18 degrees BTDC any ideas on why it’s off that much ?

 

[achris]

Thanks for the info I have another question I just replaced the ignition control module, pick up coil , ignition coil ,spark plugs and new cap and rotor it runs a lot better at lower idle but I’m still reading 1 degree BTDC till I reach 850 rpms then my timing will advance to 11 degrees BTDC at 1100 rpms then at around 2400 rpms I’m at 18 degrees BTDC any ideas on why it’s off that much ?

By all my documentation, that's about right for the engine and distributor you have. It doesn't appear to be 'off' at all.

 

[Boatdad20]

Ok thanks I was trying to get it close to the timing procedures you posted but I was not close on any of the timing numbers at idle and at high rpms I’m heading to the lake tomorrow to try it out . I originally couldn’t get it to advance at all I was a 4 degrees BTDC at 2500 rpms and couldn’t go over 2500 rpms in gear in the water