Pro Max 225 No power, low RPM

**jdewaard** · 08-23-2015, 03:19 PM

I have a 2000 Merc Pro Max 225 that has no power. I replaced the stator, trigger, switchboxes, coils, and voltage regulators with all new CDI Quick Strike ignition kit. The motor has no power and tops out at 4000 RPM. I have been talking with my friend tux974 and we are both thinking ECU/fuel pump driver. Would a bad fuel pump driver limit power and RPM's? I'm just looking for as many oppinions as I can get. I am stumped what is causing this and not sure where to look next. I already spent $1000.00 on the electrical side, now I am thinking the ECU may need to go to Simon Motorsports. I just want to be sure before spending another $600.00+. Also, I am wondering what would be the smarter choice, rebuild ECU or Brucato PCU? I am also switching to a 260 16 amp flywheel and stator when I can find one. I don't need the 40 amp charging system. I would like the lightweight factory flywheel.

Thanks,Jeff

**kurlyone2** · 08-24-2015, 08:51 AM

u can bypass fuel driver , u have two wires going into top of fuel pump one 12 volt one ground . disconnect both wires that are there now and tape them up for now . solid red is 12 volts / red with purple stripe is ground . run a wire from the purple wire in the boat harness to the 12 volt side of the fuel pump . make a short wire from a good ground and put on the ground side now when u turn key on the fuel pump runs all the time . whether it running or not ! im fighting same problem with same exact motor except mine is intermittent and when acts up wont go over 2000 rpms

**skeeter91** · 08-24-2015, 09:56 AM

Also, I am wondering what would be the smarter choice, rebuild ECU or Brucato PCU? I am also switching to a 260 16 amp flywheel and stator when I can find one. I don't need the 40 amp charging system. I would like the lightweight factory flywheel.

Thanks,Jeff[/QUOTE]

i had the same problem on my fishing motor,driver in the factory ECU.after several engine mods,the stock ECU wasnt gonna cut it!i bought one of Tony B's ACUs and could not be more pleased.in addition to the custom curve he programmed in,there are multiple adjustments that i can make via control knobs in the back of the unit that makes dialing it in super easy!

**Go Time** · 08-24-2015, 10:12 AM

A bad fuel pump driver will usually shut you down totally....no pressure no go. You could have a bad injector driver...any plugs look dry. If you have access to a DDT, try doing a static test and check the map sensor.

**TEXAS20225** · 08-24-2015, 02:29 PM

yeah it aint the fuel pump driver they work or dont may be map sensor or injector driver! my problem with reflash you dont know what your getting and when you try to get some satisfaction(because it aint what you was expecting) you usually are out to lunch on it forever , im not the right guy to give advice on brucato ecu's i own two right now and ive owned several in years past and my luck has not been good with them

**flabum1017** · 08-24-2015, 04:13 PM

How's your compression and leak-down?

**jdewaard** · 08-26-2015, 08:45 AM

Compression 132-135 all 6 cylinders. Did not do a leak down. tux974 is sending me a good ECU to try this weekend. Thanks Tony!!!!

**TEXAS20225** · 08-26-2015, 12:34 PM

yes atta boy Tony u da man

**jdewaard** · 08-26-2015, 12:46 PM

Yes Bobby, Tony has been a great help and good friend.

**tux974** · 08-27-2015, 05:53 AM

Jeff, glad to help! Hope you get things worked out and keep us posted on your findings!
Bobby, you know how sometimes finding these issues go......so we thought of trying the simple swaps.

**jdewaard** · 08-28-2015, 07:53 PM

Well...it isn't the ECU. Tried another one and had exactly the same thing. Back to square one.

**tux974** · 08-29-2015, 06:21 AM

Jeff, sorry to hear no change!
It was worth trying the ECU because sometimes when they heat up is when they decide to act up. I had one a while back act up after temp climbed.
If you want I can send you my DDT and a new map sensor to try. As you can see anything at this point is a crap shoot but worth trying!!
Maybe you should put back all the electrics you swapped since the problem is still exactly the same. Sometimes with gremlins they are not an easy find. Heck you may fix it some how and never know what it was or what you did.......

**jdewaard** · 08-29-2015, 12:56 PM

Originally Posted by tux974

Jeff, sorry to hear no change!
It was worth trying the ECU because sometimes when they heat up is when they decide to act up. I had one a while back act up after temp climbed.
If you want I can send you my DDT and a new map sensor to try. As you can see anything at this point is a crap shoot but worth trying!!
Maybe you should put back all the electrics you swapped since the problem is still exactly the same. Sometimes with gremlins they are not an easy find. Heck you may fix it some how and never know what it was or what you did.......

Where is the MAP sensor locted? I thought that was part of the ECU. Will the DDT help pinpoint my issue?

**tux974** · 08-30-2015, 06:10 AM

Jeff, sorry my typing mistake. I meant to say temp sensor. I had one go bad and backed the motor down.....so I think, the temp sensor swap fixed it...so I think....

**jdewaard** · 08-30-2015, 05:49 PM

Update....Took the boat out this weekend with the new ECU installed and the same results, no change. I swapped the OEM Pro max ECU back in and tried it, same thing. I gave up for the night. Next day I take it out and it struggles to even get on plane like it has been doing. I get on plane and then all of a sudden it starts pulling hard and the RPM's start rising. I'm excited, but as quick as it changed it went back to crappy again. I am stumped. I checked all the wiring connections and especially the plug to the ECU but no change. When the motor is in gear and I am "putzing" across the lake at 1200 RPM the motor is shaking and sounds like it is missing. It has a brand new stator, switchboxes, coils, and voltage regulators.

Fuel pressure is 36 psi from key on through all throttle positions, it doesn't change. After key off it holds at 34 psi and even held to 20 psi overnight.

Here is a couple videos at low speed.
https://youtu.be/6HvDKn_Vkys
https://youtu.be/G_FNV6RdUoU