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Donzigo
08-08-2007, 07:16 PM
I just repowered with 496s, X-drives, & all the peripheals that go with it on Big-D. I've got around 15 hours on her and I just opened her up to 5,000 the other night. With 23 inch props, it's perfect. OMG - these engines have made Big-D fly like a bird. What fun! (No, I don't know or care how fast it is ----- the fun factor is 1,000 percent)

There is an electrical issue, though. I keep blowing a 15AMP fuse next to the other 3 30 amp fuses in a harness next to the ECU unit on the top of the engine. It's a 16 guage wire that goes to the front to power the key switch. It keeps blowing the fuse and I can't figure out why. So, today, we called Mercury and they said that there is a sensor that needs to be powered by an electrical harness to stop this. Apparently, they have made a modification and when using the old 454 wiring harness, it needs this additional piece. I don't understand it yet; but, when it comes in, we'll see if it stops this fuse problem. If anyone knows anything about what I'm referring to, I'd appreciate some info. Hate to sound stupid; but, we are in the dark so much that I don't even know how to ask the question.

Other than this little problem, she screams!

mrfixxall
08-08-2007, 11:09 PM
I just repowered with 496s, X-drives, & all the peripheals that go with it on Big-D. I've got around 15 hours on her and I just opened her up to 5,000 the other night. With 23 inch props, it's perfect. OMG - these engines have made Big-D fly like a bird. What fun! (No, I don't know or care how fast it is ----- the fun factor is 1,000 percent)
There is an electrical issue, though. I keep blowing a 15AMP fuse next to the other 3 30 amp fuses in a harness next to the ECU unit on the top of the engine. It's a 16 guage wire that goes to the front to power the key switch. It keeps blowing the fuse and I can't figure out why. So, today, we called Mercury and they said that there is a sensor that needs to be powered by an electrical harness to stop this. Apparently, they have made a modification and when using the old 454 wiring harness, it needs this additional piece. I don't understand it yet; but, when it comes in, we'll see if it stops this fuse problem. If anyone knows anything about what I'm referring to, I'd appreciate some info. Hate to sound stupid; but, we are in the dark so much that I don't even know how to ask the question.
Other than this little problem, she screams!

most likely its the alternator circuit (orange wire) that may have issues:confused:

Donzigo
08-09-2007, 07:29 AM
It's actually the wire that goes to the dashboard to power the key switch.

MOP
08-09-2007, 07:33 AM
A kid with a new toy, you sure sound nice and pumped!!! Keep us up to date, will be looking forward to you comments.

Phil

DON N.
08-09-2007, 10:29 AM
Does The Key Switch Tie In With The Blower Motor ?

Donzigo
08-09-2007, 07:08 PM
Don, that's not a bad suggestion. It might. But, I haven't had the blower on. The satrboard key switch does, however go on to power all of the accesories. Both engines blow fuses so we put 30 amps of additonal power to the key switches and they still blows. We conatacted Land & Sea, Mercury's distributor, who contacted the Mercury people at Stillwater, Ok, who built the engine. They called and apologized for not sending this new wiring harness with the engines. Apparently, they now have a new harness that sends 30 amps to the key switch along with powering another solinoid or something. It should be here tomorrow and we'll see what happens. They are sending it overnight at N/C. They said that the day my engine went through the plant is the day they changed the harness and my two didn't get harness. My understanding is that when an engine manufacturer makes a technical change, they do it with the next engine down the line. They don't wait until a model change at the end of a year. They said that if my engines had been a few more engines down the line, the new harnesses were being put on the engines. My engines were built in May of 2007 and shipped to Pompano warehouse in June. Stay tuned. It's kinda fun chasing this little squirell all over the tree just to see where it ends up. I sure wish I had a schematic of the 496s. I'd love to know what this fuse assembly powers.

Donzigo
08-15-2007, 09:07 AM
PROBLEM SOLVED ----------------

The 454 gets it's power from the battery then sends it to the keyswitch, then on to the accessory breaker bar to provide it's power. The new 496s do not have enough extra power to run the accessories off of the engine harness going to the key switch. So, a separate wire must be run from the battery (#8 wire) to the dash to be connected into the accessory bar, to provide power. If the orignal harness is used, the 496 will blow the 15 amp fuse on the top of the engine next tot he ECM unit. The new harness has a 40 amp fuse thus providing plenty of power.

Now we are ready for some serious boating!

gcarter
08-15-2007, 09:14 AM
PROBLEM SOLVED ----------------
The 454 gets it's power from the battery then sends it to the keyswitch, then on to the accessory breaker bar to provide it's power. The new 496s do not have enough extra power to run the accessories off of the engine harness going to the key switch. So, a separate wire must be run from the battery (#8 wire) to the dash to be connected into the accessory bar, to provide power. If the orignal harness is used, the 496 will blow the 15 amp fuse on the top of the engine next tot he ECM unit. The new harness has a 40 amp fuse thus providing plenty of power.
Now we are ready for some serious boating!
Sounds like a good idea for a boat like yours w/a lot of accesories.