None taken. That's your opinion and you are certainly entitled to it.Who am I to try to change your mind.
However, mine isn't an opinion. It comes from tearing into well over 100 525's. I'll say this much and leave it at that. Every one that we have torn into has had spring pressures less than 110 pounds on the seat. These are all engines between 175-350 hours. The majority of them had less then 105 pounds and numerous ones had less then 100 pounds. There is not one cam manufacturer out there that would agree that those springs pressures are sufficient for a cam with the lift and duration that the 525 has. Those light springs can and do cause numerous other problems.....we've seen them and fixed them, many times over. As far as I'm concerned from a business standpoint, I think Mercury is doing a fine job. I hope they continue. They account for a large portion of my gross income.

I'm certainly not trying to be argumentative or a smart ass, so please don't take this the wrong way. You have your opinion and are completely entitled to it. But I have the facts and plenty of pics to back it up.
Eddie

I think it was mid year 98 when the 500 efi's came out. I guess they could be either HP500's or 500 EFI's in a 99 boat.
Eddie

Your opinion is based on the fact that you have been fortunate enough not to have had a failure during this interval. I had a rocker failure at 200 hours that spit needle bearings everywhere and trashed the engine. There are plenty of other cases like mine that support the assumption that the 525 has weaknesses in the valve train, mainly the valve springs. When my rocker failed, we tested the spring pressure on the OEM springs, they were less than 100#. That is not enough to control the valve and the rocker had worn out around the polylock indicating it was bouncing around. First thing I did after replacing that engine was change the springs and rockers on the other two engines. Your entitled to your opinion and you've been lucky. There are plenty of 525's that have gone 400+ hours without a hiccup and there are plenty that have blown up unexpectedly at what would seem like very low hours. I am a huge fan of the 525; I have three of them. But as an owner of these engines you have to understand the risks and decide whether you want to spend a little money preventively or risk a catastrophic failure that kills half your boating season.

That sounds about right. My HP500EFI was a 2001, and when I sold it around 200 hours or so, the new buyer confirmed with Bob Teague personally via serial number that the cutover to some better valvetrain components was done before my engine was built.

I purchased a pair of 525 long blocks fresh from the machine shop from a friend of mine, I spoke to the machine shop and they said the springs were within spec and they didn't replace them, my question is there a way to determine whether these are original Merc springs or have they been replaced, currently these springs have no more than 15 hours of run time on them. They are setting on my stands, do I replace them now ?? Ive not even ran the valves on these yet. And if I do replace them what do I go with. Thanks

If he checked them, then he should know what the pressures are. Ask him. Also, one identifying feature of the stock springs is their short install height. They only go in about 1.820". We change to a 10* retainer and lock which gives us about .090 more available install height. This opens up the spring selection tremendously. On a stock 525, we use the ISKY 8005A.
Eddie

And that first year of the 500 efi was goofy. They used leftover parts from the 500 hp. We rebuilt 3 of them a few yrs ago. I wanted to replace the oil thermostat and had to get one for a hp 500 instead of a 500 efi. The following year got different parts. Guess Mercury used up what they had laying around. lol
Eddie

That's a DEAL! Some shops charge that just to pull and reinstall the engines alone!

Either way I support freshing the top ends BEFORE there's issues, and 200-300 hrs is the max I would go personally.

Ironically, the Mercury Racing service manual for the 525 specifically says installed height of 1.850", yet all three of my engines had nothing higher than 1.810" on the OEM springs. I have since replaced them all with Isky 8005A's and 10* retainers and locks at 1.850"; that was two seasons and 125 hours ago.

thanks