My 525 builds

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05-14-2018 | 01:32 PM

#21

rvtransport

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Joined: Feb 2006

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From: Manitowoc, WI

Quote:

Originally Posted by JRider

Isnt that a wee bit lean?

We actually did send ecm's back to add little more fuel to the curve. I have AFR gauges in boat so will monitor.

05-14-2018 | 08:41 PM

#22

35 zr donzi

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My 525 EFI's have 350 easy hours on them ,when do you think i should do the heads ?

05-15-2018 | 01:08 AM

#23

Griff

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Joined: Oct 2000

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From: Omaha/LOTO

Quote:

Originally Posted by 35 zr donzi

My 525 EFI's have 350 easy hours on them ,when do you think i should do the heads ?

Probably should have done them 50 hrs ago.

05-15-2018 | 09:10 AM

#24

rvtransport

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From: Manitowoc, WI

Quote:

Originally Posted by 35 zr donzi

My 525 EFI's have 350 easy hours on them ,when do you think i should do the heads ?

The problem with running them with hours and week valve springs is the valves float little and beat the crap out of valve train. I would at least change valve springs every 200ish hours IMO.

06-18-2019 | 05:38 PM

#25

endeavour32

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From: Chicago, IL; Onekama, MI

RV-

What did you end up getting for a speed increase, with the mods you did to your 525 EFIs?

06-19-2019 | 07:52 AM

#26

rvtransport

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From: Manitowoc, WI

5mph gain. Best is 90mph now. Will run 85 to 87 loaded every day. Before was 78 to 80 loaded and 85 perfect conditions. Have almost 40
hours on engines now and run really nice.

06-19-2019 | 08:17 AM

#27

IGetWet

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Joined: Sep 2013

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From: Wisconsin

These dogs can hunt, I can vouch for that! One of the funnest rides I’ve been on.

06-19-2019 | 01:47 PM

#28

cmoore7

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Joined: Feb 2017

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From: St. Clair, Michigan

What are you running for drives? Those holding up too?

06-19-2019 | 01:55 PM

#29

rvtransport

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From: Manitowoc, WI

XR's. No issues yet. Figure Mercury puts them on 600sci motors and I am similar in power. I am careful getting on plane but let them rip when rolling regularly.

06-19-2019 | 02:31 PM

#30

VoodooRob

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Joined: Jul 2011

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From: Cleveland Ohio

Quote:

Originally Posted by rvtransport

XR's. No issues yet. Figure Mercury puts them on 600sci motors and I am similar in power. I am careful getting on plane but let them rip when rolling regularly.

Mercury played a sick joke with this pairing. I will say with the factory tune my 600SCIs fell on their face below 3,000 rpm, found out it was programmed in to keep the drives alive. Our previous stock 525/XR boat pulled harder getting on plane.