2002 Mercruiser 5 liter MPI Distributor Timing

[joedm2000]

Serial number = 0m345217
Some Background... Because of a small oil leak in the back of the intake manifold, I removed the intake manifold and replaced the gaskets.

I ran it after the repair on muffs and it ran great at idle and at higher RPMs.

Put the boat into the water today. It idled fine and put the boat into gear and it ran fine util I got above 1300rpms when it started hesitating and sputtering. If I went back below 1300rpms it ran fine again. If the engine is not under load it runs fine. Any help is appreciated!!.

 

[Fun Times]

Chances are after this type of service work the distributor housing Assembly isn’t “phased in” correctly as there is a special process to reinstall the distributor assembly and or the distributor cap has been compromised/damaged to where it won’t run correctly now.

Distributor And Ignition Components

Distributor And Ignition Components

www.mercruiserparts.com

 

[alldodge]

might help

 

[joedm2000]

might help
View attachment 362571

I marked the shaft relative to the intake manifold and the rotor relative to the housing before removal. When reassembling, I got the marks within + or -1/16 of an inch. Could this still be the issue?

 

[Fun Times]

I marked the shaft relative to the intake manifold and the rotor relative to the housing before removal. When reassembling, I got the marks within + or -1/16 of an inch. Could this still be the issue?

It could., try slowly turning the assembly both ways a few degrees in both directions to see if it will run better before going through the reinstallation process.

The following should help guide you with installing the distributor if needed…,

https://forums.iboats.com/attachments/installing-hvs-pdf.87763/

 

[joedm2000]

It could., try slowly turning the assembly both ways a few degrees in both directions to see if it will run better before going through the reinstallation process.

The following should help guide you with installing the distributor if needed…,

https://forums.iboats.com/attachments/installing-hvs-pdf.87763/

Thanks for the info!!...I ordered a new cap and rotor to eliminate any issues with them. My plan for the distributor "phase issue", is to go to TDC on cylinder 1 and check if everything lines up correctly without removing the distributor. Make any adjustments if needed... I believe this should cover all my bases. Any Thoughts??

 

[QBhoy]

Diz cap and fresh fuel will sort her out.

 

[joedm2000]

I'm chasing a rough running issue after I replaced intake manifold gaskets. It was suggested that I look at distributor timing. Please see the attached picture. Is this within spec? This is the closest I could get tang to the mark. The motor is at number 1 cylinder TDC. Thanks!!

 

[dubs283]

There is a procedure for installing and clocking the distributor in the oem manual. If you haven't removed/disturbed the distributor it's most likely fine.

When was the last full tune up: plugs, wires, cap/rotor, fuel filters?

 

[alldodge]

I'm chasing a rough running issue after I replaced intake manifold gaskets. It was suggested that I look at distributor timing. Please see the attached picture. Is this within spec? This is the closest I could get tang to the mark. The motor is at number 1 cylinder TDC. Thanks!!

No that's not close enough IF it was at TDC. If you are at TDC then lift the Dizzy out enough to disengage gear and rotate

Should have also also posted this one to your previous thread
https://forums.iboats.com/threads/02-mercruiser-5-liter-mpi-rough-running.756751/#post-5769891

 

[joedm2000]

There is a procedure for installing and clocking the distributor in the oem manual. If you haven't removed/disturbed the distributor it's most likely fine.

When was the last full tune up: plugs, wires, cap/rotor, fuel filters?

I did remove the distributor to replace the intake manifold gaskets and marked the placement of the distributor. I believed I got it back in the correct orientation. I just want to make sure it looks right.

 

[joedm2000]

No that's not close enough IF it was at TDC. If you are at TDC then lift the Dizzy out enough to disengage gear and rotate

Should have also also posted this one to your previous thread
https://forums.iboats.com/threads/02-mercruiser-5-liter-mpi-rough-running.756751/#post-5769891

Sorry..I should have kept my original thread. Thank you for the information...Any suggestions on how to get distributor closer to the mark? It appears if I go to the next gear on the distributor the tang points too far to the other side of the mark.

 

[alldodge]

Sorry..I should have kept my original thread. Thank you for the information...Any suggestions on how to get distributor closer to the mark? It appears if I go to the next gear on the distributor the tang points too far to the other side of the mark.

Maybe, first tell me how you determined the motor is at TDC?

 

[joedm2000]

Maybe, first tell me how you determined the motor is at TDC?

 

[alldodge]

Thanks, issue with that is if the damper notch can be a few degrees off. To make sure its a true TDC would need a stop bolt or a micrometer probing the top of the piston.

Your motor is running and with that as @Fun Times mentioned in the other thread, loosen the Dizzy and ever so slightly more it just a few degrees (really small amount) and lock it back down. Take it out and see how it does. If it gets better but still not right, try to go a hair more. If it gets worst go the other direction

The SB below is how to adjust and if need be to make a cheap tool to get the timing exact

 

[joedm2000]

Thanks, issue with that is if the damper notch can be a few degrees off. To make sure its a true TDC would need a stop bolt or a micrometer probing the top of the piston.

Your motor is running and with that as @Fun Times mentioned in the other thread, loosen the Dizzy and ever so slightly more it just a few degrees (really small amount) and lock it back down. Take it out and see how it does. If it gets better but still not right, try to go a hair more. If it gets worst go the other direction

The SB below is how to adjust and if need be to make a cheap tool to get the timing exact

Thanks for the detailed response.!!

 

[southkogs]

I've combined both topics into one thread.

 

[achris]

I'm chasing a rough running issue after I replaced intake manifold gaskets. It was suggested that I look at distributor timing. Please see the attached picture. Is this within spec? This is the closest I could get tang to the mark. The motor is at number 1 cylinder TDC. Thanks!!

My reading of the manual, and having done it a few times but not recently, is that is incorrect. That position it is in is the STARTING position of the installation process (while the distributor is still out of the engine). The rotor will actual move as you stab it in and the gear engages with the camshaft gear.

I've stripped out the dissy installation pages (of the Merc manual) and attached them. Read it through carefully, you see that those alignment marks are for the rotor BEFORE it goes in the engine.

Chris...

 

[Lou C]

And are you sure that the intake bolts were torqued properly and you don’t have a vacuum leak?

 

[achris]

And are you sure that the intake bolts were torqued properly and you don’t have a vacuum leak?

That's a good point. And be aware that Vortec intake screws are set WAY lower than non-vortec. I've seen more than one engine messed up because the intake screws were over tightened. (leads to leaks in the gaskets...)

Chris.