Technical question for a 350 magnum

[Lubejobs42]

I have a buddy we are helping with his boat and he is driving a a Fu@#ing wall! Can anyone tell me the timing on a 350 Magnum MPI and which wire is the ground wire for the timing?
Thank you

[Ratickle]

Hey Gino,

Just saw this and noticed it wasn't in the tech area where the tech experts would notice it.

Don't know the answer, but I'm moving this into the engine tech area where you'll hopefully get an answer. At least it should get noticed there when they get to checking for questions.

[MOBILEMERCMAN]

Off the top of my head it is a white/black wire with a female bullet that is in the box thingy that mounts to the riser. If that is not right get the serial number and I will investigate further.

[Trim'd Up]

It is 8 BTDC at idle and 32 BTDC at either 3200 or 3800rpm, can't remember which when it is all in. I believe the wire you need to ground is white.

[Boat Tech]

I have a buddy we are helping with his boat and he is driving a a Fu@#ing wall! Can anyone tell me the timing on a 350 Magnum MPI and which wire is the ground wire for the timing?
Thank you

To help you out correctly We will need your engine serial number, Because you have a MPI style engine there is no one wire to ground out, There is either a wire connector you will need to jump, Or you will need the service manual to see the correct way to just drop the distributor in, And there is no timing to set you just need to be in the right area with the
distributor, Then the cam and crank sensors do the rest. If my guess is right you will need service manual number 31, Starting on page 4B-9.

If you need info on how to get a service manual online let me know, They are easy to find if you know where to look, But before you use the service manual I talked about you need to make sure it's the right one using your engine serial number.

[catastrophe]

This is the kind of sh!t that makes me proud of this joint

[MacGyver]

If you need info on how to get a service manual online let me know, They are easy to find if you know where to look, But before you use the service manual I talked about you need to make sure it's the right one using your engine serial number.

I have found many manuals online, but no High Performance manuals. Something I'd like to add to my collection someday.

[MOBILEMERCMAN]

350 Mag is not High Performance.

Yes, some { It depends on what series ign it has on it.} MPI engines have a wire to ground for setting timing. Later engines had a plug or you need the DDT to place in service mode.

If it has a Merc Thunderbolt ignition I would bet it has a white/ black wire. If it has a GM style distributor it will likely need the plug {mentioned above} or a scan tool to set timing.

Serial number?

[Ratickle]

Come on Gino, where'd you go???????

[MacGyver]

350 Mag is not High Performance.

Hi Jim. Yeah, I know a 350 isn't HP, LOL! I was just saying I'd like to find and add HP manuals to my collection. Like HP #1 - HP #7.

[Boat Tech]

Hi Jim. Yeah, I know a 350 isn't HP, LOL! I was just saying I'd like to find and add HP manuals to my collection. Like HP #1 - HP #7.

Sorry But I only know of the non HP Service manuals, But most of the stock models can be found over at iboats, In the I/O sticky area.

[jhenrie]

The engine may be equipped with the "thunderbolt IV" ignition system. This can be identified by the ignition control module with knock sensor that is mounted to the distributor. The IV sysem uses the same dist. cap as the older more familiar Mercruiser HEI. The T-bolt IV sytem has a "MBT" or mean best timing circuit which automatically adjusts timing to current load conditions. In order to set base timing you have to disable that feature. If you have this type of system look for a PURPLE/WHITE lead near the distributor, it should be covered but not connected to anything. This is called "lead 13" which when connected to a good ground will override the system and put it in base timing mode. You can then set the timing from there.

MPI says you need the scan tool !!

[MOBILEMERCMAN]

Off the top of my head it is a white/black wire with a female bullet that is in the box thingy that mounts to the riser. If that is not right get the serial number and I will investigate further.

The engine may be equipped with the "thunderbolt IV" ignition system. This can be identified by the ignition control module with knock sensor that is mounted to the distributor. The IV sysem uses the same dist. cap as the older more familiar Mercruiser HEI. The T-bolt IV sytem has a "MBT" or mean best timing circuit which automatically adjusts timing to current load conditions. In order to set base timing you have to disable that feature. If you have this type of system look for a PURPLE/WHITE lead near the distributor, it should be covered but not connected to anything. This is called "lead 13" which when connected to a good ground will override the system and put it in base timing mode. You can then set the timing from there.

MPI says you need the scan tool !!

Off the top of my head could not be confirmed. I recall a white wire but, can't confirm which motor as I sit here at this time.

jhenrie is correct.

[fixxxer22]

I put two mags in a four winns horizon and i had to take it to a buddy that is a volvo penta field service engineer to hook the scan tool up to let me time it. they were MEFI4 i think you can get a plug to jumper the 2 ports together or use a jumper wire. but you can see the plug on the side of the MEFI4 relay box on the riser. It also is the diagnostic port (i think)