Mercury Racing blue motors: 500EFI, 525 EFI, 575 SCI. Pros/cons/maintenance/etc.
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Bob T thanks for the write-up.. exactly what I was looking for Anyone who has anything to add feel free.
Does the 575 need 93+ or 91+ octane? Premium is scarce at marinas up here so will have to avoid that motor probably.
I like the idea of the 525 I heard that you can send your headers back to CMI for re-working for a very reasonable cost... a good way to make that setup more reliable?
Does the 575 need 93+ or 91+ octane? Premium is scarce at marinas up here so will have to avoid that motor probably.
I like the idea of the 525 I heard that you can send your headers back to CMI for re-working for a very reasonable cost... a good way to make that setup more reliable?
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http://www.mercruiserparts.com/selec...asp?type_id=8H
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Bob T thanks for the write-up.. exactly what I was looking for Anyone who has anything to add feel free.
Does the 575 need 93+ or 91+ octane? Premium is scarce at marinas up here so will have to avoid that motor probably.
I like the idea of the 525 I heard that you can send your headers back to CMI for re-working for a very reasonable cost... a good way to make that setup more reliable?
Does the 575 need 93+ or 91+ octane? Premium is scarce at marinas up here so will have to avoid that motor probably.
I like the idea of the 525 I heard that you can send your headers back to CMI for re-working for a very reasonable cost... a good way to make that setup more reliable?
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Problem is that Merc told CMI what grade stainless to use (lower) and to bypass the heat treating of the finished tubes. So what happened, the headers crack leak water in the engine and if not caught will quickly destroy it in short order. It seems standard CMI's are fine but the Merc/CMI headers really gave CMI a bad rap. Now you can buy the CMI header for around $4000, I believe the inferiour Merc version is $8000. Another example on merc's outragious mark-up.
At least as far as I can remember reading... He's right.
Last edited by SDFever; 11-09-2010 at 09:33 AM. Reason: spelling
#16
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Bob T thanks for the write-up.. exactly what I was looking for Anyone who has anything to add feel free.
Does the 575 need 93+ or 91+ octane? Premium is scarce at marinas up here so will have to avoid that motor probably.
I like the idea of the 525 I heard that you can send your headers back to CMI for re-working for a very reasonable cost... a good way to make that setup more reliable?
Does the 575 need 93+ or 91+ octane? Premium is scarce at marinas up here so will have to avoid that motor probably.
I like the idea of the 525 I heard that you can send your headers back to CMI for re-working for a very reasonable cost... a good way to make that setup more reliable?
I'm running 8PSI with a 871, 8.75 compression, 93 octane, no issues (twice the boost, 1.25+ CR). I have run low on gas and mixed 93 with 89 dock gas. Not my preferred way to go, but it beats running out of gas, and getting towed in. I just stay out of boost range and run part throttle.
BTW, when it comes to selling or buying most performance boats, they usually carry better retail with blue motors. Insurance is easier too. They are listed in Kelly Blue book. Ilmor may be? Aftermarket, probably not.
Regards,
Steve
Last edited by Steve Zuckerman; 11-09-2010 at 05:59 PM.
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hey Bob T another question for you... what type and weight of oil do you run in your 525? Anyone else who has suggestions please throw them out there. I take great care about what type and weight of oil to put in an engine.
I.e. should I run 20-50 synthetic (amsoil or mobil1) or is it better to run conventional oil and change it frequently?
Plan on doing changes at no more then 25 hour intervals.
I.e. should I run 20-50 synthetic (amsoil or mobil1) or is it better to run conventional oil and change it frequently?
Plan on doing changes at no more then 25 hour intervals.
#18
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The 525 EFI is a great motor. The block is CNC machined, it has steel H-beam rods, forged pistons, aluminum heads, top quality valve train components, the hottest cam of any N/A Mercury Racing engine, Cometic head gaskets (later models) and on and on. Mine is an '07 vintage and still has the factory seal in place. No header problems here but I may have an "improved" version. It will burn the cheapest gas available without problem. It is an extremely popular motor and I recommend it. The oil issue is very complicated and everyone has their opinion on that so after reading a crap load of oil threads I decided to play it safe and use the 25w40 Quicksilver oil recommended by Mercury. I change it 3 times per season; About every 20 hours. I change it at the end of the season and run it on the hose so that it is stored with clean oil coating the parts. It needs a top end rebuild at about 200 hours partly because of the high valve lift and beating that the valve train takes. It also sounds very cool. Here's mine. BTW, it has full Zeiger steering now . http://www.youtube.com/watch?v=i7H6zNFH8f0
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with my SBC motors I do the oil changes like you have , just regular quiksilver 25-40 about 25 hour intervals. But w/ 525 I want to give it the best treatment possible. Also it will be used motor so is it advisable to switch to synthetic?
#20
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Here is my take: For years full synthetic was a strict no no because it was too slippery and could cause the roller lifters to skid on the cam. Now that Bob Teague is sponsored by Amsoil it is magically OK to run full synthetic. I'm still not convinced. I'm sticking with 25w40 Quicksilver which is what the Mercury service manual for the 525 calls for. You will get a lot of different answers if you ask what oil to use. Hang on!