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  1. apw30534

    ECU pinout/wiring diagrams ???

    This is the GI ECM in my boat:
  2. apw30534

    ECU pinout/wiring diagrams ???

    This is the GXI ECM: (I dont have a serial number to go with it)
  3. apw30534

    ECU pinout/wiring diagrams ???

    Pin #58 is "tach output" which is where it throws me off... as this should be the signal telling the tach needle where to point. Pins #25 and #26 are "speed pos and neg" which I *think* is voltage returning to the ECU from the tach. Only reason I think this is because of the statement in the...
  4. apw30534

    ECU pinout/wiring diagrams ???

    I ordered some Volvo Penta manuals and wiring diagrams. Interesting stuff. What I find most interesting is pin #25 and pin #26 on my ECU... Apparently the ECU gets a separate signal directly from the tach. I find it odd that it uses a tach signal when it already has cam and crank sensor inputs...
  5. apw30534

    2008 Chaparral 275 SSI 8.1 Volvo Penta GXI-J Soft Alarm Issues

    And really makes the old-timers like me, wish for a carburetor and HEI distributor again. 😆
  6. apw30534

    First time pulling an engine questions

    I will also add... seeing that this is a saltwater boat and theres already a ton of corrosion everywhere... AND its raw water cooled... there's no way I would put that engine back in the boat without doing a full teardown or complete replacement. I can only imagine how bad it looks inside the...
  7. apw30534

    First time pulling an engine questions

    Throw that plastic timing cover in the garbage where it belongs and replace it with an aluminum timing cover. Holley makes a direct-fit replacement that is worth it's weight in gold. If you dont replace that plastic timing cover, I promise you WILL have problems with it. I know from firsthand...
  8. apw30534

    ECU pinout/wiring diagrams ???

    No scanner as of yet... but that is on my to-do list. I did contact Bob awhile ago about my current ECU and he said he doesn't (or cant) do anything with these EGC ECU's. In hindsight... my life would have been much easier if I had just purchased a Merc powered boat instead. The aftermarket...
  9. apw30534

    ECU pinout/wiring diagrams ???

    The spare ECU and harness came from a reputable guy and apparently was a complete running (but worn out) 8.1GXi. No idea what boat it came from. (It could be for a Sea Ray or a Cobalt... and completely incompatible with my Chaparral.) He rebuilt the engine for his Chevy pickup and sold me the...
  10. apw30534

    ECU pinout/wiring diagrams ???

    Yeah this is my concern. I have the serial number from my boat engine and have both ECU's and both harnesses, but no practical way to compare them and no absolute confirmation of the model year on the loose harness/ECU package. They are both the same ECU plugs and both are drive by wire, but...
  11. apw30534

    ECU pinout/wiring diagrams ???

    I've got a 2007 VP 8.1 Gi-H in my boat. I also have a 8.1GXi ECU and harness from a similar year boat, sitting on my workbench. Both ECU's interchange with the boat harness, but the GXi ECU will only start and run the engine for a few seconds, then shuts down. I'd like to compare harness wire...
  12. apw30534

    2007 8.1 Gi converted to rear-mount closed cooling

    Yeah I'm super pleased with the speed. My previous Chaparral was all done @42mph. This current 256 might even hang with a few (very few) jet-ski's. lol
  13. apw30534

    ECM Swap ? Plug and play ???

    It would sure make my life easier if someone could hack this ECM and change a couple things. Im not asking for any kind of ozone-depleting, smog-creating tune... just a higher rev limit and a factory-like tune that works with the HO camshaft.
  14. apw30534

    ECM Swap ? Plug and play ???

    I've actually considered swapping to a carb and distributor setup, just to simplify things, but fear it might make the boat slower. lol I have a carbureted Dart intake for the 8.1 already... so it would just be a matter of picking the right size carb and tossing an HEI distributor in it... all...
  15. apw30534

    2007 8.1 Gi converted to rear-mount closed cooling

    Just a quick update.... I've had the boat out several times and the engine temp stays rock-steady @ 160 degrees. I couldn't be happier with this kit and I'm sure the engine will live longer with antifreeze inside it. Also just saw my best top speed last Friday.
  16. apw30534

    Duoprop hub replacement ?

    Just a quick update... I managed to bend the tips on my rear F6 prop at the boat ramp like an idiot... so I swapped on these F7's to try. Much to my surprise they actually seem to be OK. Doing some math... 17% slip @ 41.2 mph and 11.8% slip at 56.1mph. The F6's are at a shop getting repaired...
  17. apw30534

    Duoprop hub replacement ?

    Here's a quick video I made: Also shows some hammer marks in one blade that will need to be fixed.
  18. apw30534

    2007 8.1 Gi converted to rear-mount closed cooling

    Yeah that is another concern. I dont know if my tank will handle the added heat load.
  19. apw30534

    2007 8.1 Gi converted to rear-mount closed cooling

    I've been eyeballing them... just havent found the right setup yet. The biggest issue is that I need the extra 6" riser blocks between the manifold and SS risers... which is not a common thing and they are pretty spendy. It is nice that Merc has some aluminum manifolds floating around out...
  20. apw30534

    Duoprop hub replacement ?

    Anyone done this yet ? Wondering how much of a job it is. I found a pretty nice set of props and only have $750 into them. Upon closer inspection it looks like the hubs are spun and/or walking around inside the props. I can buy a pair of hubs for around $300 but not sure how much of a pain its...
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