525s ?
 

Im looking at a boat with 525s in it. 2004 with 280 hours. I have read so much bad stuff about the headers its making me reconsider making an offer on the boat. I cant imagine dropping $60K on the boat knowing that I will need at the minimum new headers and what ever else. Im at a standstill right now.

Any input on this purchase?

there are tons of threads on the 525's. in a nut shell:

1. Check the headers
2. Springs get weak if top end hasn't been done
3. Probably time for new head gaskets

Do your homework and inspection on subject boat. Factor in above items when making an offer. If the deal doesn't make sense walk away. It's that simple.

Here is the early 525 header info in a nutshell. Boats with a salt water history have a higher rate of header failure. Staggered boats have a higher rate of failure. If there are hot spots on the header by the head, the header has overheated due to poor water flow and has a higher risk of failure. The headers just need to slightly over heat to discolor, in most cases the engines will not have set an alarm. Here are some things to look for and ask about: Has the Mercury Header Flow Service Bulletin been performed on the headers? This routes all the water thru the header and eliminated a bypass hose. Has the owner changed impeller and housing at a minimum once a season? By changing the impeller/housing at least once a season the owner has helped to keep the headers as cool as possible. At 280 hours the engines should have had valve springs done at a minimum by now and is approaching a top end re-fresh. Has the owner addressed that properly? Have the headers ever been pressure checked? If so, how often? A seller who has done preventative maintenance and tests will be selling a better boat. Before final purchase have engine test done, pull some plugs, check the oil. The good news is there are alternatives to $5-$6k/pair in CMI headers. Half the price but not as rock and roll looking, so there are alternatives. Keep in mind, a 10 year old header is just that and nothing lasts forever in the boating world.

60k for pretty much any boat in decent shape with 525's and 280 hrs is pretty cheap.
The engines alone are worth over 30k.

I had a conversation this week with a guy that just spent 82k rebuilding a pair of 525s and XRs....I said for 82k he file have gotten brand new 520s and new drives with 2 years of warranty! He said like everything, if he knew the total cost going in he would have done things differently! I suspect he thought he would do it cheaper but once it got rolling it was a case of, we'll change this and the bill kept escalating.

Where is this guy?? I'll detail his boat for 10K.

Thats the base price. He's gonna need some extras/upgrades. You know, a 2nd coat of wax etc.:party-smiley-004:

I am right now doing complete re-builds due to header failure $38,000 with new headers. Call Eddie @ Young Performance, great guy who will ell u what they will need at this point. That does sound like a good price (maybe).

After re-reading this, like Griff said, a 525 boat for $60k is either a smokin' deal or a smokin' pile of sheet.

Another problem with the 525's is the rod bolts. When they give way, it takes the short block with it. The rod bolts were changed later, but your 04 will have the old ones like my 05 did. Also, the head gaskets suck in the early 525's. Basically your opportunity for failures are rod bolts, head gaskets, springs, and headers. Other then that, they are great:) That said, there are a ton of guys out there with 500+ hours on older 525's. I just wasn't one of them...

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!

Exactly what I paid and exactly what was done to mine. All preventative on my end and no issues at all.

Sounds like I basically have to expect these costs if I buy this boat. Stainless Marine has headers for $3500 each plus Install charges.

Is sending them to CMI for repairs actually a viable option?

I agree but keep in mind these engines are ten years old. Who has a car that is that old in perfect order? Verado's are awesome but they have their issues as well. A computer goes out (happens often) there goes 4k.

Stainless marine requires new tails and you must modify (drill holes in heads) to use them. Not a huge deal, but know that going in. Hardin (I think) has a new system coming out in April which will be a direct replacement and will work with your old tails. That will be the way to go in the near future.

Yes CMI fixes these often and I have heard many good experiences with the process. Main thing is keep checking them while you own the boat.

Keep in mind you are hearing all the bad stories but there are a ton of 525's without issues a hundreds of hours..

"Quote Originally Posted by mike tkach View Post
joew,i never heard about rod bolt issues with the 525s.can you give more information about it?

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"

That's exactly what happened to mine!

Good reading as I have a pair of 05's that haven't been touched with 180 hours , so all this is ahead of me . What I would like to know is how much hp diff. is there between the sweeper header and the e-top.........knowing full well the exhaust bolt locations in the head have to be moved and new tails made up but it would allow for other heads or engines in the future.

14,000 for two sets of headers doesn't seem realistic to me and in my case I have a set of e-tops and tails sitting in a boat going up for sale.

Usually the 250 to 400 hr range possible outdrive problems. Any 12 year boat - bellows, shift cable and its bellows, check engine alignment and u joints very closely and the water circ pump. Prob coolant flush & change as well

Gen x's will cost you about 10-11. Sucks, but not 14. I have no idea on the e top vs. sweeper hp loss, but I'd expect no loss at all. I think I remember reading that the only loss from the sweeper to stainless marine was the bling. Horse power didn't change.

The 525 is a great engine. Pressure test the headers, which is easy to do. Valve springs, retainers and keepers at 400 hours due to the aggressive cam. I'd do a scan on the engines to see if they've had the snot run out of them. I would do a leakdown or compression test before purchasing in addition to the engine scan. My 525 has the newer CMIs and they are fine after 8 years of freshwater use.

I can't find the invoice now but my top end refresh with new springs, retainers and keepers along with leakdown test and visual inspection of valves, pistons and bores with a remote camera was under $1,000.

I wouldn't call new springs a top end refresh. I had almost 7k in parts alone on mine

525's are great motors, i have friends that have put 800 hrs on them,
if compression is good i would just replace the springs
take the headers off and sell them then get a set of stainless marine ( probably cost you about the same as what you sell the cmi's for )

Our top end refresh on 500's was right around 8k for (2). Lifters and valves alone is almost 1500 a motor. Add R&R, spings, locks, keepers, gaskets...adds up fast.

I've got a 2003 Donzi 38ZX. 525efi. 500 hours. Bone stock, never opened until this winter. Leak down test showed bad head gasket between 4&6. Compression was about 120 psi. Fresh top end with valve springs, valve job, shave the heads and all new gaskets. Now the compression is about 140 psi. 140 psi is what the book rated the compression at. $3000. Did all the labor myself. Original headers pressure tested and still good! Great motors. I think a lot of guys alter and blow the engines up.

I would also suspect your zip code has a lot to do with your rebuild costs. TnT or Potter probably gets more money than a shop at LOTO.

correct statement,when the valve springs get weak the valves don,t seal well[espically the exhaust].changing just the springs won,t restore the valve seal.the heads need to be removed for a valve job and to check the flatness of the head.by this time the stock head gasket is suspect but it is getting replaced anyway,hopefully with a good quality fel pro gasket.imo the issue of weak springs could have been corrected by useing better valve springs to start with but the bean counters at mercury marine stopped that,their attitude is,JUST GET IT PAST THE WARRANTY PERIOD.generally this needs to be done at the 250 hour mark.

800 hrs without ever removing the heads?

Generally speaking, the 525 EFI camshaft, isn't very mild. I mean it is, but it isn't. Its way more camshaft than say a 502 magnum. 502 Mags have .483 valve lift. 525 EFI, has .630 valve lift. I think by 300 hours, you've done well to get that time, with and engine with a camshaft like that, and making over 1HP per cubic inch. 502 mags, 700 hours isnt an issue normally. its the mild cam that makes it live.

The 525 is kind of a hot engine, and certainly isn't going to go the distance like a mild 330 Mercury cruiser engine will time wise. The HP500, 500EFI, 575sci, are all high performance engines, and all require normal top end attention around the 250-350 hour mark. I just dont think one can "expect" them to go twice that long.

The stout cam shouldn't cause the valves to wear. I did springs, etc. at about 400 hours as maintenance. There was no need to remove the heads. I also went with stock spec springs since they've worked fine for over 400 hours and I'm not going to second guess Mercury on their choice of springs. IMO this is a very good engine. Remember that when you're on top you will have haters.

Hate to say it, but unless you removed the heads, and actually checked the guide clearances, valve seat condition, valve condition, and so on, you're statement is purely a guess, in regards to what is, or isnt' needed.

At 400 hours, I'd be willing to bet the guide clearances, seat concentricity, and valve job, is no where close to what it was when new.

After time, when valve guides wear, things get loose. The valve no longer may seat itself concentrically on the valve seat. it might "leak down test" ok, but at 5000rpm, the results may be different. The relationship between the valve and valve seat, on an endurance engine, is critical. Not even so much as power is concerned, but for valve cooling, as that is where the majority of exhaust valve cooling takes place, when it contacts the seat. Valve seat cut widths, are only as good as the concentricity of the valve to seat. If the valve is only contacting 60% of the seats cut, when closed, due to a sloppy guide or workmanship, the valve can overheat.

Valves, and valve seats, have a cycle life, just like anything. Hence why different materials are used in different applications. One might get 300 hours out of a valve job with iron or powder metal seats and stainless valves, and might get 50 hours out of a titanium valve with copper beryllium seats.

I know you get a bit sensitive about the 525 mercury engine, because you have had good luck with yours. I personally think Mercury's package are about as good as it gets. But at the end of the day, its an Edelbrock cylinder headed, crane cammed, manley valved, pac' springed 502 GM based engine. It is not above the laws of physics. The sad truth is, there are many out there who have suffered the shortcomings of this engine, and frankly, I don't think its right to keep saying in so many words, that they are doing something wrong, or simply unlucky. Running a pair of 525's in a 42 Fountain or 39 Cigarette, is quite different than in a 22 Donzi. With that being said, I know of many who run the crap out of their 525's, and they have had good luck. It is a great engine, but not perfect by any means. I think alot of guys in the past saw "525EFI" merc engines in the boat they were buying, and assumed they simply are dead nuts reliable long life engines that just won't cost them an arm and a leg to maintain. Unfortunately, for some, that just wasnt the case.