Mercury racing 525 EFI rpm and prop
08-01-2019, 06:56 PM
#31
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Location: Camden, DE
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08-01-2019, 07:24 PM
#32
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08-01-2019, 09:41 PM
#33
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I don't think it is marine rated.
08-02-2019, 02:25 AM
#34
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I don't think it's a problem. The ECU is sealed inside a box with a lot of foam so I don't think it Will take damage or moisture, and I never leave the ECU in the boat, it's pretty hard to steal without a ECU. But as it is right now, I'm pretty sure I have a head gasket waiting to give in so I wont be using the boat this year anymore. Wouldn't be a big thing to take the heads off and chance the gaskets but we have like a month of real Summer left here and then it starts to cool down and be pretty damp outside. So I think it's better to pull the engine out of the boat and inspect everything and be sure it works next year rather than rushing to get it working for a few weeks this year. We have Pokerrun here next weekend so it sucks a bit but it is what it is.
08-04-2019, 01:19 PM
#35
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As stated above the 525 EFI is one well thought out and very reliable package. I have two, 12 years without a single hiccup. Just went thru them and found not a single thing that indicated a need to rethink what Merc racing built. We did up grade the valve springs and used Crower SS rockers in place of the Crane. All else was not dicked with, case of "If it ain't broke, don't fix it".
A plan here might be to work toward getting the motor back to where Merc had it. I think that would satisfy your goal. Then if you feel you want more RPM you can use the Whipple reprogram and reset the limiter to 6000 along with a few other little tweeks.
A plan here might be to work toward getting the motor back to where Merc had it. I think that would satisfy your goal. Then if you feel you want more RPM you can use the Whipple reprogram and reset the limiter to 6000 along with a few other little tweeks.
08-04-2019, 01:58 PM
#36
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Total timing should be 32 to 34 BTDC.
You need to determine whether your "24 degrees" is in reference to TDC, or if it is "degrees of advance" from baseline. If it is the second, and if initial timing is 10 BTDC, then ADDING 24 degrees of advance to that will result in 34 degrees total.
When making a top end run, make sure fuel pressure doesnt drop off at high revs. And shortcoming or obstruction can "hide" at lower speeds.
Plug wires are one place to look. One cylinder missing results is a loss of 60+ hp.
Finally, are you familiar with drive trim angles and trim tab settings? Trimming the boat to run "free" dramatically affects top speed and wide open rpm.
It's worrisome to hear of a cam swap and 'mildly tuned" without specs on the cam grind and lobe separation and its installed lobe center. Many "performance car" cam grinds are unacceptable for marine performance usage.
Give more details and we will all try to help.
MC
You need to determine whether your "24 degrees" is in reference to TDC, or if it is "degrees of advance" from baseline. If it is the second, and if initial timing is 10 BTDC, then ADDING 24 degrees of advance to that will result in 34 degrees total.
When making a top end run, make sure fuel pressure doesnt drop off at high revs. And shortcoming or obstruction can "hide" at lower speeds.
Plug wires are one place to look. One cylinder missing results is a loss of 60+ hp.
Finally, are you familiar with drive trim angles and trim tab settings? Trimming the boat to run "free" dramatically affects top speed and wide open rpm.
It's worrisome to hear of a cam swap and 'mildly tuned" without specs on the cam grind and lobe separation and its installed lobe center. Many "performance car" cam grinds are unacceptable for marine performance usage.
Give more details and we will all try to help.
MC
