500EFI vs 525
#1
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Thread Starter
500EFI vs 525
What are the differences and the pros & cons of a Mercruiser 500EFI and a Mercruiser 525? I assume that the latter makes 25 more horse power but is it a better engine? What about durability, maintenance, cost to operate etc.
In other words, all things be equal, how should it influence a decision in purchasing a used boat?
Thanks,
Padraig
In other words, all things be equal, how should it influence a decision in purchasing a used boat?
Thanks,
Padraig
#3
More on 525 headers... I CANNOT STRESS THIS ENOUGH. If you are looking at a boat with 525's in it, you MUST examine the headers very carefully and if possible have them pressure tested for leaks. Also, do compression and leak down tests but these will not find leaking headers unless the damage has already been done. The OEM CMI headers come in two varieties. Those with leaks and those that will leak. There are some lucky guys who've had no problems but there's a LOT of others including myself, some who've experienced catastrophic engine loss as a result of water ingestion. Having said all that, I would absolutely buy another boat with 525's in it, but they require diligent maintenance and inspection of the headers at least once a season.
#4
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Thanks. So far it sounds like the 525 is better unless there are header problems. Hour wise, when will header problems show up? Or do you just figure on the expense of purchasing new CMI headers?
What about the internals? I "think" the 500 is based on a 502 block and the 525 on a 496 block. Are the pistons, crank, etc. Equal?
What about the internals? I "think" the 500 is based on a 502 block and the 525 on a 496 block. Are the pistons, crank, etc. Equal?
#6
Thanks. So far it sounds like the 525 is better unless there are header problems. Hour wise, when will header problems show up? Or do you just figure on the expense of purchasing new CMI headers?
What about the internals? I "think" the 500 is based on a 502 block and the 525 on a 496 block. Are the pistons, crank, etc. Equal?
What about the internals? I "think" the 500 is based on a 502 block and the 525 on a 496 block. Are the pistons, crank, etc. Equal?