525 EFI - VIRGIN hours
11-27-2017, 03:01 PM
#12
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2004 525 with 310 hours. No issues at this time. Engine is in a 28 foot Howard Bullet. As a side note just replaced the lower gears in the ITS XR drive with Sport Master lower. It had 300 hours on it.
11-27-2017, 05:42 PM
#13
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2006 525's, bought this boat with couple over 40 hours, showed minutes over 4K when purchased. Since purchased just oil and filters every 25 or so, Valvoline Racing only. Little over 300 as we speak and these have been flawless, everything would point to all is good in the heart of the beast. This boat will run, never had the chit beat out of it, will still run a number today. I do believe that the 525 EFI is one of the finest engines that Merc has ever put out there. Take care of these and with some love they will serve you for a good long time.
Not saying that these might not benefit from a top end refresh,,,,,, just saying that they don't show the fall off that would indicate the top ends are spent.
Not saying that these might not benefit from a top end refresh,,,,,, just saying that they don't show the fall off that would indicate the top ends are spent.
11-27-2017, 07:13 PM
#14
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Location: Belle River, Ontario / Lake St. Clair
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Just had motors opened up at 340 hrs. Both stock. 1 motor was still tagged, sealed. The other had been opened at some point. Valve seat pressure was really low around 100 pounds. Valve train was in tack, but showed signs of wear and lash. Full valve train replaced. Head gaskets were starting to seep between cylinder walls. Cylinders still have a cross hatch. Heads are in great shape. Changing out composite head gaskets with multi layer steel. Port matching heads to intake and exhaust. Opening up heads around exhaust valves. Ive ran Amsoil Dominator full syn in it past two seasons. Royal Purple was in them before that. No failures. Zero issues. Run er hard as she'll let me. Top 85.7 MPH at 5400 rpm. I show the .7 because its not 86mph. YET.....
11-28-2017, 06:34 AM
#15
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This is my second set of 525 efi engines - 220 hours @ mostly low rpms, compression test was perfect. My first set in a 2003
Sonic had over 400 hours on them without being touched. Compression test on those at time of sale was good, but couple of plugs on one of the engines were showing signs of oil - and that engine was using oil (my guess was guides and or seals).
Sonic had over 400 hours on them without being touched. Compression test on those at time of sale was good, but couple of plugs on one of the engines were showing signs of oil - and that engine was using oil (my guess was guides and or seals).
11-29-2017, 08:43 AM
#17
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To have it done to include lifters and push rods $5-$6k a side. Find out the definition of "top end" from one shop to another when doing price comparison. At your hours if leakdown is good definitely throw springs on it and run to 300-350 hrs then do complete top end.All depends on the engines though, some are dropping rockers at 150hrs, some have seeping head gaskets at 200, others run flawless to 500 hrs. We did our last boat at 320 hrs.
Last edited by VoodooRob; 11-29-2017 at 08:45 AM.
11-29-2017, 09:41 AM
#18
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Great information guys. Mine still sealed at 355 hrs. running great. Engines now winterized until April/May using the recommended 6 gal. tank with outboard oil and Sta-Bil and fogging oil through intakes. Ran compression check this summer and all 16 were 155-160.
03-11-2019, 12:25 PM
#19
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05 Fountain fever 29' still factory sealed and on original springs 678 hours and counting. 525EFI. Boat is just as fast as it was the day I bought it with 400hrs. Doing the springs now just in case...
03-11-2019, 01:21 PM
#20
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Gold Member
Previous boat, 30 Superboat, 525efi, XR/w ITS. Bought it with 130 hours. sold it with 280 hours. No engine issues. Swapped out the CMI's with Stainless Marine, (BTW, no difference in performance). Broke 2 XR's while I owned it. Happier now with OB's!
