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HELP !!! My Merc 525 EFIs are over revving !!!

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HELP !!! My Merc 525 EFIs are over revving !!!

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Old 09-05-2021 | 02:35 PM
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Check the toe of the drives, I.e. pointing in or out from each other. If the tie bar adjustment is way off it could effect slip %
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Old 09-05-2021 | 03:02 PM
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Originally Posted by Barryama1124
Hi, yes complete transom assembly with gimbals were replaced with the same drives I had before. I can’t sander the question on drive height however if the same drives were installed, I assume the answer would be a yes lol. Sorry I’m not fully familiar with boat mechanics, but if a learning curve lol

I really appreciate your input though thank you

He was asking if the transom of the bost was changed. Not outdrive transom assemblies.

My wuestion - did mph go up with the rpm’s ? Stay same ? Go down ?
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Old 09-05-2021 | 03:04 PM
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Originally Posted by Unlimited jd
Check the toe of the drives, I.e. pointing in or out from each other. If the tie bar adjustment is way off it could effect slip %
They looked perfect because I am completely anal however I will measure them to make sure the mechanic did not screw that up, I didn’t realize that could cause slip but that makes total sense thank you
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Old 09-05-2021 | 04:38 PM
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Originally Posted by SB
He was asking if the transom of the bost was changed. Not outdrive transom assemblies.

My wuestion - did mph go up with the rpm’s ? Stay same ? Go down ?
yes sir the transom was changed however the outer fiberglass 1/4 in wall was left in intact.
they just added the fiberboard on the inside then cud the holes through the fiberboard using the exterior shell if you wish as a template so the holes remain in the same place.

As for the speed going up with the RPM’s I have no clue, he said he backed off when he heard the warning horn go off.

I’ll see Tuesday when I open it up, I usually get 86, 87 mph fully trimmed at 5200 so I’ll see On Tuesday and get back to you guys for sure with an update

Thanks again guys I really appreciate your help
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Old 09-05-2021 | 07:13 PM
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Originally Posted by Barryama1124
I’m not sure what there set at but I can say that I have never been able to exceed 5200 and never had a problem running them for extended periods of time at 52 but now there revving 5400 and of course the warnings kicks in which is a pain in the ass but would prefer to fix the issue rather that just throttling back if ya know what I mean lol
so are you going faster?
I see above you answered it.

Last edited by sutphen 30; 09-05-2021 at 07:16 PM.
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Old 09-05-2021 | 10:50 PM
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Originally Posted by Barryama1124
Hey bud, I can’t answer that because I haven’t tested the boat myself, it was taken out for adjustments by the mechanic. It was just what he told me and before I take it out, I wanted to run my problem thought offshore before taking it out this coming Tuesday.

I might change the props if I can gain some top end out of it so long As I don’t need a football field length to get planning LOL
Your mechanic prob trimmed the drives higher than you do or ran it different than you do
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Old 09-06-2021 | 07:03 AM
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Originally Posted by Griff
Your mechanic prob trimmed the drives higher than you do or ran it different than you do
good morning, I guess we’ll find out on Tuesday LOL. On another note, do you have any idea what the cost is for rods, rockers and springs only per head? I just want to make sure I didn’t pay for the parts. Thanks in advance and have an awesome day
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Old 09-06-2021 | 08:06 AM
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You had all that work done and gained 200 RPM? Sounds like a win to me. Just about every story that begins with I had major mods/rebuilds ends with, "I lost performance" or "something isn't right".

Let us know how it goes after you run it yourself and the worse that could happen is you get new props and go even faster.
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Old 09-06-2021 | 08:23 AM
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Originally Posted by Barryama1124
good morning, I guess we’ll find out on Tuesday LOL. On another note, do you have any idea what the cost is for rods, rockers and springs only per head? I just want to make sure I didn’t pay for the parts. Thanks in advance and have an awesome day
You need to put " push " in front of this in your case, when you say rod's us gear heads think connecting rods which can be 10-15 times the price of push rods, without the brand name of the components replaced it would just be a guess on our part about cost, and I hope they did a valve job at the same time.
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Old 09-06-2021 | 08:29 AM
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Originally Posted by F-2 Speedy
You need to put " push " in front of this in your case, when you say rod's us gear heads think connecting rods which can be 10-15 times the price of push rods, without the brand name of the components replaced it would just be a guess on our part about cost, and I hope they did a valve job at the same time.
lol I get it but I did mention it was for heads and although I’m not gear head, I don’t thing push rods are in the heads bahahah…

kidding aside, no I did not do a valance job cuz nex year I’m considering putting 560 or 565 twins in it in place of 525,s. Research showed that at the very least, springs, pushrods and rockers would suffice. I’m just curious what the cost should be compared to what I paid for the parts assuming there upper middle to high end quality parts 😎
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