thanks for the replys, so how much is a top end refresh gonna cost on both engines?

Seems like im almost better off looking for a boat with 500s Im not sure its worth the extra 3-4 mph

I did a ton of research on 525's before I purchased my boat last year. There is a ton of scary stuff out there which everyone has already listed. At the end of the day, the mercury stuff will sell before custom (not because it is really better) which is why I went ahead and pulled the trigger on my boat. On the headers, you can send them to cmi and get them fixed for a reasonable fee ($200-300) I hear. You can/should also make a drain system so when you are done using the boat each time, you can turn a valve and drain the headers. Many engine/header issues happen when all the water drained from the header into the cylinder between usages. The rest happen when the small/no leak opens up cause it is hot.

Also, a clean T525 boat at 60k is a great deal!

Depends what you consider a top end. Just springs or full heads being machined, etc. I'd say a minimum of springs will be $1000 per side if you have it done. Heads machined, new gaskets, new springs, misc. is probably 4,000 a side. This is my guess as my only experience was doing top ends while replacing new bottom ends:(

joew,i never heard about rod bolt issues with the 525s.can you give more information about it?

I spent 12k on top end refresh last year for 2 motors. That's on the the high side but I have all the best parts available, not merc stuff. That's everything, springs, lifters, valves, rockers. Yours may not need everything but mine are ready for whipples. 525's are great motors, if your worried about headers just make the sale contingent on pressure checking them. They're very easy to check

That's just crazy, you could buy a pair of 700's for that price

I wasn't sure if he was bragging about the 82K but when I said you could have had T-N-T install brand new motors/drives/assemblies with 2 yrs of factory warranty for less than 82K he clammed up quick. I wouldn't have spent that on rebuilt anything.

I read about it from one of Eddie Young's posts before I purchased my boat. I think he has seen around 15 break in his time. That may sound like a lot, but I'd guess he does 30+ 525's a year (I have no idea) so that is only 5%+/- over ten years. That said, mercury used a cheaper rod bolt in the early years (say pre 07) which will snap off at the head of the bolt. Next thing you know you have the bottom half of the rod through your oil pan which sucked:)

At first I thought that is a strange place for a hose clamp:)---look in front of starter
https://www.dropbox.com/sc/5awtzfkcn...lghTNL9IyvC2Ba

Then I realized my mercury blue engines are more expensive then my old mercury black ones..

Threads like this make it pretty obvious...to me at least...why boats with Verados are getting so popular.
I'm bummed out after just reading some of your guys' experiences with 525s....and I didn't have to foot the bill!