Mercrusier 350 MAG MPI - RPM issue under a load

[wbas1]

The motor may have been rebuilt once before and a 383 (6.2) rotating assembly may have been installed prior. Not saying it was, just a possibility


Normally it is not done, but can be moved ever so little, a degree or 2 can change things. There is a Merc Bulletin which shows how to build a $10 tool to get the timing exact. I can post if you want it

please post. Greatly appreciate it.

 

[alldodge]

Srv Bul 2011 11R2

 

[wbas1]

Srv Bul 2011 11R2

If I am reading this correctly, my distributor does not have a cam sensor. I only have a crank sensor. Can I still do this procedure?

 

[alldodge]

It doesn't have the cable connecting to the sensor but your Dizzy should have the connector which to the sensor inside

 

[wbas1]

It doesn't have the cable connecting to the sensor but your Dizzy should have the connector which to the sensor inside

Yes it does but I might see what I have done wrong all along. This is how I set the timing.

• got the engine to top dead center
• Put the distributor in and aligned it to the #8 cast in the housing
• I never moved the engine to 1 1/16" past TDC then installed the distributor and aligned it to the #8

Did I set base timing incorrectly??

 

[alldodge]

Looks right, first 2 bullets
As you said, did not move to 10 and install

 

[QBhoy]

27.7 Baja Crusier. Yes they were replced. I have to look at the plugs since they were replaced when I had it at a mechanic

Did they put the proper plugs in it. These don’t take or run well with normal plugs. Need iridium in them.

 

[wbas1]

Looks right, first 2 bullets
As you said, did not move to 10 and install

so I did not need to move the motor 1 1/16 then install the distributor

 

[wbas1]

Did they put the proper plugs in it. These don’t take or run well with normal plugs. Need iridium in them.

I am going to check tonight

 

[QBhoy]

I am going to check tonight

Might not be your issue, but I know for sure, they run crappy Witt normal plugs and not too much better with platinum. Manual calls for minimum platinum and prefer iridium. Ngk 5599’s from memory. Really expensive

 

[wbas1]

Might not be your issue, but I know for sure, they run crappy Witt normal plugs and not too much better with platinum. Manual calls for minimum platinum and prefer iridium. Ngk 5599’s from memory. Really expensive

thank you. I will check what they put in

 

[wbas1]

Looks right, first 2 bullets
As you said, did not move to 10 and install

I will be making the tester tomorrow & testing tomorrow night. i will reply once I have an update. Fingers crossed.

 

[alldodge]

so I did not need to move the motor 1 1/16 then install the distributor

Lets say I didn't understand fully about the 10* or 1/16. If your saying you need to move the rotor about that much past prior to dropping it in so the Rotor will align correctly", then Yes it should be done.

I'm saying after the Dizzy is installed it needs to align with the point or the 8

 

[alldodge]

Did they put the proper plugs in it. These don’t take or run well with normal plugs. Need iridium in them.

Don't fully agree, but right now that isn't the problem MR43LTS will work just fine and is what they originally came with

 

[wbas1]

I will be making the tester tomorrow & testing tomorrow night. i will reply once I have an update. Fingers crossed.

I was not able to get to the boat last night. trying to do it tonight.

 

[QBhoy]

Don't fully agree, but right now that isn't the problem MR43LTS will work just fine and is what they originally came with

They are platinum AD. Minimum requirement. My earlier post just suggesting to make sure it’s at least them.
Unfortunately I’ve known a few of these to have some idiot throw the normal carb plugs in these, like the br6. Just don’t work.

 

[wbas1]

Update: I have returned from vacation so I will be going down to the boat tonight to make the final adjustments to the distributor per alldodges service bulletin from Merc. Hopefully the weather cooperates that I can water test it.

 

[wbas1]

Lets say I didn't understand fully about the 10* or 1/16. If your saying you need to move the rotor about that much past prior to dropping it in so the Rotor will align correctly", then Yes it should be done.

I'm saying after the Dizzy is installed it needs to align with the point or the 8

Update: I went down to the boat today and made the necessary adjustments to the distributor/HVS per the service bulletin and unfortunately no change. Runs great at the dock but once you try to get on a plan it has no getup and go.

 

[alldodge]

New motor and 150 psi all cylinders
New ECM from Merc
Firing order is correct and there is no misfiring, just low power
Timing is dead on correct using the timing tool per bulletin

For me, not the sharpest tool
Only thing left is there might not be enough advance in timing, or not enough fuel, or its not a vortec 350, or the wrong reluctor wheel was installed

Take a advance timing light and connect to number 1. Can be at the dock and rev motor up to see how much advance your getting

Look behind the heads on the block rear deck for a casting number. It will be a 6 to 8 digit number with no letters.

 

[wbas1]

New motor and 150 psi all cylinders
New ECM from Merc
Firing order is correct and there is no misfiring, just low power
Timing is dead on correct using the timing tool per bulletin

For me, not the sharpest tool
Only thing left is there might not be enough advance in timing, or not enough fuel, or its not a vortec 350, or the wrong reluctor wheel was installed

Take a advance timing light and connect to number 1. Can be at the dock and rev motor up to see how much advance your getting

Look behind the heads on the block rear deck for a casting number. It will be a 6 to 8 digit number with no letters.

Just so you know what I did with the timing tool. I got the motor to TDC, then I rotated the motor to 10degrees BTC. Once I had the motor to 10 degrees BTC I used the timing tool to get it set dead on. I will get the other information tomorrow