Mercrusier 350 MAG MPI - RPM issue under a load

[wbas1]

And more fuel doesn't necessarily mean more power

I would say differently in my case

 

[wbas1]

I was wondering when I am at WOT, good the spark be late and not making full power?

 

[alldodge]

If your getting full advance, no
If your not getting full advance, yes

You have tested for this prior and said you were getting advance

 

[wbas1]

If your getting full advance, no
If your not getting full advance, yes

You have tested for this prior and said you were getting advance

Yes you are correct. I am getting full advance at the dock to 24 degrees

 

[Scott Danforth]

Yes you are correct. I am getting full advance at the dock to 24 degrees

24 degrees of advance with base timing if 8 degrees is 32 degrees total

Or are you only seeing 24 degrees total?

 

[wbas1]

24 degrees of advance with base timing if 8 degrees is 32 degrees total

Or are you only seeing 24 degrees total?

I am 99% sure. I will test it again today at the dock. I will check what base timing is then advanced. If I have 4 at base full advance would be ?

 

[Scott Danforth]

I am 99% sure. I will test it again today at the dock. I will check what base timing is then advanced. If I have 4 at base full advance would be ?

Simple math would say 4+24=28

Not sure why you would set your base timing low at 4

Plus the 350 mag MPI should have a specific timing setup procedure in the Mercruiser manual

 

[wbas1]

Simple math would say 4+24=28

Not sure why you would set your base timing low at 4

Simple math would say 4+24=28

Not sure why you would set your base timing low at 4

I did not set it that way. The computer did. I just put the distributor in at TDC.

 

[alldodge]

You have the flat top cap. There is no adjusting timing with a timing light, computer does it all

 

[wbas1]

You have the flat top cap. There is no adjusting timing with a timing light, computer does it all

If the computer is setting the timing correctly, what should I see at idle and WOT after the motor is warmed up?

 

[alldodge]

Doesn't state in manual, but I would guess it should be same as all SBC and 24* from base timing.

 

[wbas1]

I did some tests today on the timing,
5.7 ECM 6 degrees at 700 rpm’s. 22 degrees at 3000 rpm’s and did not change going higher.
I put the 6.2 ECM back on and tested. Same results as the 5.7 ECM. The motor runs better with the 5.7 ECM.
I spoke with the previous owner and he always ran the boat at 4200 rpm’s with no problems. He could get it to 5k.
Only items that were replaced by him was the outdrive because of electrolysis and the bellows. The 6.2 ECM was on the motor from day 1.

 

[alldodge]

Only items that were replaced by him was the outdrive

I would bet a different ratio

 

[wbas1]

I would bet a different ratio

He told me it was the same as he had.
Does the total advance # look correct?

 

[alldodge]

Talk is cheap, and he to may have been told it was the same.

It looks good enough, you would get more as the rpms increase

 

[wbas1]

Talk is cheap, and he to may have been told it was the same.

It looks good enough, you would get more as the rpms increase

I am going to confirm the ratio this week.

 

[wbas1]

Update: I wanted to pull the plugs again and see what they look like. I am not an expert on reading the plugs but they do not look good.

 

[Scott Danforth]

you either have injectors not firing, or you have water in the cylinders on half your plugs

your white electrodes should be a nice caramel color

 

[wbas1]

you either have injectors not firing, or you have water in the cylinders on half your plugs

your white electrodes should be a nice caramel color

I tested all the injectors and they are pulsing. They could be clogged. I would think If I had water in the cylinders they would get hydro locked.

 

[Scott Danforth]

I tested all the injectors and they are pulsing. They could be clogged. I would think If I had water in the cylinders they would get hydro locked.

send the injectors out to be cleaned and flow tested

water does not automatically mean hydrolock