We hurt the 496....
#551
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From: SW Ohio
Brad,
Yea, Apparently the smartcraft setup limited the trim using the 3 wire sender... Since you're ditching that sender and going with only analog and trim limit switch, its probably just worth running new wires straight to the helm per that picture I sent in post #544. I'm assuming you are removing the entire engine harness and using one for your specific setup so I don't know how using the existing transom harness would play out.. I'd just start from scratch for trim limit, or eliminate it all together.
Yea, Apparently the smartcraft setup limited the trim using the 3 wire sender... Since you're ditching that sender and going with only analog and trim limit switch, its probably just worth running new wires straight to the helm per that picture I sent in post #544. I'm assuming you are removing the entire engine harness and using one for your specific setup so I don't know how using the existing transom harness would play out.. I'd just start from scratch for trim limit, or eliminate it all together.
We ripped the entire 496/555 harness out by the roots. Theres literally nothing left of it.
Thanks. Brad.
#552
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Joined: Jun 2021
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From: SW Ohio
Guys,
Any reason for this?

Back side of trailer switch, showing both output lugs in use

Both wires joined with a butt connecter, with two wires on the other side

These two wires joining up with the two “down” wires
There is a purple wire running in tandem along with both the “up” and “down” wires all the way to the transom, at which point I lose track of them and I’m not willing to commit to the carnage required to further trace them.

There are only the two wires terminating at the trim pump solenoids. Where did the two purple “tandem” wires go?
Are these extra wires all part of the SmartCraft setup, for the purpose of the “auto-trim” function (that I don’t have)? I don’t need to replicate that, right?
Thanks. Brad.
Any reason for this?

Back side of trailer switch, showing both output lugs in use

Both wires joined with a butt connecter, with two wires on the other side

These two wires joining up with the two “down” wires
There is a purple wire running in tandem along with both the “up” and “down” wires all the way to the transom, at which point I lose track of them and I’m not willing to commit to the carnage required to further trace them.

There are only the two wires terminating at the trim pump solenoids. Where did the two purple “tandem” wires go?
Are these extra wires all part of the SmartCraft setup, for the purpose of the “auto-trim” function (that I don’t have)? I don’t need to replicate that, right?
Thanks. Brad.
#553
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Joined: Jan 2005
Posts: 4,820
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From: IL
Brad,
I have not read all your post above but sounds like you might be having trim issues? and not sure if this has been mentioned.
if your having issues with your trim keep in mind input and output goes through your pcm,
last time i upgraded a 496 mag to a 496mag HO i send the ecus to whipple for recalibrating and when I got them back the trim did not work on either engine,
I resend them back they redid the calibration ,still didnt work.
talked to dustin and he wasnt sure why that was happening so he send out 2 new ecu, plugged them in and trim worked fine,
I have not read all your post above but sounds like you might be having trim issues? and not sure if this has been mentioned.
if your having issues with your trim keep in mind input and output goes through your pcm,
last time i upgraded a 496 mag to a 496mag HO i send the ecus to whipple for recalibrating and when I got them back the trim did not work on either engine,
I resend them back they redid the calibration ,still didnt work.
talked to dustin and he wasnt sure why that was happening so he send out 2 new ecu, plugged them in and trim worked fine,
#554
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Joined: Jun 2021
Posts: 3,475
Likes: 2,099
From: SW Ohio
Brad,
I have not read all your post above but sounds like you might be having trim issues? and not sure if this has been mentioned.
if your having issues with your trim keep in mind input and output goes through your pcm,
last time i upgraded a 496 mag to a 496mag HO i send the ecus to whipple for recalibrating and when I got them back the trim did not work on either engine,
I resend them back they redid the calibration ,still didnt work.
talked to dustin and he wasnt sure why that was happening so he send out 2 new ecu, plugged them in and trim worked fine,
I have not read all your post above but sounds like you might be having trim issues? and not sure if this has been mentioned.
if your having issues with your trim keep in mind input and output goes through your pcm,
last time i upgraded a 496 mag to a 496mag HO i send the ecus to whipple for recalibrating and when I got them back the trim did not work on either engine,
I resend them back they redid the calibration ,still didnt work.
talked to dustin and he wasnt sure why that was happening so he send out 2 new ecu, plugged them in and trim worked fine,
I don’t blame you for not reading it all. It’s several hundred posts deep at this point. It’s been quite the roller coaster ride.
We ripped the 555 and its harness out by the roots. The engine now has a Holley HP ECM, and the trim is no longer going to be going through the ECM.
Thanks. Brad.
#555
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From: SW Ohio
Guys,
We've got ONE last wire from the cannon plug to the ECM harness to sort out: the audible alarm. As it happens the builder has never had or worked on a boat that still had a functional one, and has never really dealt with it. Anybody know how it’s wired in the typical Merc configuration? Is it always hot, with the ECM providing a switched ground, or is it the other way around? In the meantime, he is working on configuring the ECM on parameters to trigger said alarm. Water temp, oil pressure and fuel pressure. Any other suggestions?
To update…. I tHiNk we have the engine aligned and locked down. I just today got the trim wiring wrapped up. I began prepping parts for dabbing up the exhaust after ditching the SilentChoice. My welder guy is supposed to come to the shop tomorrow and, with a bit of luck, we should have that wrapped up. Although, I do need to acquire some new wet exhaust hose to make the connection from the tails to the tips. I’m going a local marine service shop will have some on hand. Not holding my breath.
Thanks. Brad.
We've got ONE last wire from the cannon plug to the ECM harness to sort out: the audible alarm. As it happens the builder has never had or worked on a boat that still had a functional one, and has never really dealt with it. Anybody know how it’s wired in the typical Merc configuration? Is it always hot, with the ECM providing a switched ground, or is it the other way around? In the meantime, he is working on configuring the ECM on parameters to trigger said alarm. Water temp, oil pressure and fuel pressure. Any other suggestions?
To update…. I tHiNk we have the engine aligned and locked down. I just today got the trim wiring wrapped up. I began prepping parts for dabbing up the exhaust after ditching the SilentChoice. My welder guy is supposed to come to the shop tomorrow and, with a bit of luck, we should have that wrapped up. Although, I do need to acquire some new wet exhaust hose to make the connection from the tails to the tips. I’m going a local marine service shop will have some on hand. Not holding my breath.
Thanks. Brad.
Last edited by Brad Christy; 05-08-2025 at 09:38 PM.
#556
Yes, configure the safeties through a 2D advanced table, and have it shut the engine down the for critical issues. Low oil pressure, hot engine temp.
#557
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Joined: Jun 2021
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From: SW Ohio
Yup. I'm leaving the configuring to the builder. He's familiar. I'll just farq it up.
I don't know if the HP has provisions for derating or shutting down or just triggering the alarm. Again, I'm leaving that to the builder. I'm sure he will get it right.
Thanks. Brad.
#558
Rookie,
Yup. I'm leaving the configuring to the builder. He's familiar. I'll just farq it up.
I don't know if the HP has provisions for derating or shutting down or just triggering the alarm. Again, I'm leaving that to the builder. I'm sure he will get it right.
Thanks. Brad.
Yup. I'm leaving the configuring to the builder. He's familiar. I'll just farq it up.
I don't know if the HP has provisions for derating or shutting down or just triggering the alarm. Again, I'm leaving that to the builder. I'm sure he will get it right.
Thanks. Brad.
#559
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Joined: Jun 2021
Posts: 3,475
Likes: 2,099
From: SW Ohio
Guys,
A little update….







We spent some time getting the exhaust fabbed up after removing the SilentChoice diverters.
I’ll have the powder coated in heat resistant black after we get it running and everything sorted out.
Thanks. Brad.
A little update….







We spent some time getting the exhaust fabbed up after removing the SilentChoice diverters.
I’ll have the powder coated in heat resistant black after we get it running and everything sorted out.
Thanks. Brad.
#560


