525 EFI how many hours...
 

I think I am going to buy a new boat with 525efi's..... anyone have an idea of the life expectancy or how many hours they are running before top end refreshing?? tired of going down the road
with blowers and rebuilds

thx

If you're not too hard on them, 400 hours before top ends

I was told its about the same at the 500efi's witch is between 300 and 400 hours.

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what is the cost to have MercuryRacing do the complete refresh on the 525 EFI's ?

Trick question.........Many new 525's have been torn down with relatively low hours when the sh!tty headers leak! :eekdrop:

Usually a complete rebuild from Merc is 12,000 - 14,000

I have / had over 450 hours on mine.... they are currently at Potter Performance getting rebuilt

Tooooo Many!!!

I was told around $12,000 as well.

How much at potter?

A good engine build is usually about 8,000- 9,000

U rebuild 525s after the headers let go and ruin em

100hrs
200?

20?

Ticking time bomb

Bingo....

should have mentioned boat....new to me.... 270 hours on 525's if I buy it obvioulsy I should replace the headers.... and hope for 400 hours?? or do the top ends right away? I guess a leak down test would be in order?? Fak... I was assuming 500 hours before I had to touch them..:eekdrop:

One of my friends has almost 500 hrs and hasn't done nothing yet and they are still running strong

Mine have 460hrs on them. They still run very strong, compression test and leak down was great when I bought the boat last summer. They have year old Hardin marine headers on them. I'm going to do the top ends out of peace of mind but we put almost 20hrs on it after buying it at the end of July and they run great! The top gun gets 84-86mph WOT.

If they haven't been ran hard you should be good. Do a leakdown and compression test on the motors and have the headers pressure tested also before you buy. If you get boat I would replace headers or bare minimum have them pressure tested every year. My opinion they are the most reliable/best "blue" motor mercury has built.

+1... this is the best advice.. definitely compression and leakdown test, and pressure test the headers at least once a year and pull spark plugs periodically to check for evidence of water intrusion...

...completely agree.. putting the header issues aside, the 525 is a bulletproof motor..

At 250 hours or so, you need to replace valve springs and rocker arms only. You can do the top ends later or a complete rebuild.

I have 330 hrs on mine and no problems. I also have the original equip CMI headers with no issues. Victory Marine down here recommends at 350-400 hrs for top ends light to avg use or earlier for heavy use. Someone at Merc Racing when I called with this question said he had recently heard of a Formula cruiser with 800 hrs on 525's with nothing done still running strong.

X2!

Rebuilt both of mine at 400 hours after both sets of headers leaked into the cylinders. :mad: CMI Gen X headers now on as part of the rebuild.

At these rebuild prices it is hard to believe they are selling used 525's in the classifieds for 25K+ a pair........After you buy headers it really gets expensive.....Makes brand new bobtails look reasonable at 31K each! (Proboats.com)

I've had a bunch of 525's in the shop lately. None of them had more than 250 hours. One of them with 210 hours had 6 broken rocker arms. We were just going to replace the springs, retainers, locks and seals. However, there were needle bearing everywhere. We had to pull the engine, remove the intake and oil pan and find all of the needle bearings. Luckily,none made it to the pan. They did make it into the lifter valley. How none went past the cam I don't know. I couldn't believe it.

Another had 191 hours that broke a connecting rod and launched it out of the pan. We pulled the engine to find a 3" piece of rod in the bilge. Needless to say, it made a mess.

All of the others (5) required pulling the heads to change the head gaskets. They all had the composite gaskets and the gaskets were all going between every cylinder. The heads all had low spots between the combustion chambers that required surfacing the heads. None of them would have lasted much longer. All of these engines were pre 2005, so they didn't have Cometic head gaskets. Now, they were all in 2005 and 2006 boats, but the engines were pre 2005.

The ones that do have the Cometic head gaskets also required surfacing. The head gaskets made quite an indentation in the heads. The heads seem to be kind of soft.

The other thing is the springs. They are chicken chit. They only have about 120#'s on the seat. If you plan on running any rpm over stock, you better change the springs. We have been putting 10* retainers and locks in place of the stock 7*. With the stock 7* setup, the install height is extremely short (about 1.820). There really aren't any other springs out there that will go in place of the stock PAC springs, and they are just to light on the seat IMO. The 10* retainers and locks give an extra .100 of install height. That's open up the spring options tremendously. Then you can have a spring with a more realistic seat pressure.

Here are some pics of the carnage.
Eddie

Looks like junk...
We have never had springs last more then 70 - 80 hrs

Nice pics Eddie! How is it some 525s go a long time without incident and others blow up in half the time? Is it over revving? The wrong oil? Failure to winterize? What is your opinion?
Thanks, Andy

Here are another set that we have now. The tailpipes leaked, causing reversion. The salt water ate the cylinder head from the inside out. Once enough of the exhaust port was gone, the header leaked externally and blew water everywhere in the bilge, causing everything to rust. That entire side of the engine is a big, nasty, rusty mess. Luckily, we were able to salvage the head, since Merc wants stupid money to replace them. After we ground out all of the corrosion, there were areas that required over 1/2" of material to be replaced. We were able to build it back it to where it's as good as new. We had to surface the exhaust face of all 4 heads since all 4 tailpipes were leaking. On top of all the other work and expenses, the tails need to be replaced as well.

I've been meaning to start a thread on them but just haven't had the time lately. If you have a 525, I would check the following:
1-Change the springs, retainers, locks and seals if they are even close to 200 hours
2-Check the rocker arms for failure
3-If they are pre 2005 engines, pull the heads, surface them and replace the head gaskets with Cometics and GM head bolts with ARP's
4-Pressure test the headers
5-You can't pressure test the tails but you can run water through them to check for leaks. Also check the dam in the lower portion of the tail for cracks. If that dam cracks, it will allow water to creep up the pipe

Here are some pics of what happens when the tails leak.
Eddie

Forgot one very important thing..........Don't forget to change the muffler bearing.

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muhahaha :)

Are the 500EFI's pretty much the same??? I have a friend that has a 35' Cig and about 300 hrs, Seems to run good...

That's a salt water muffler that's why.

So Eddie what is it? What do you think early failures are due mainly to??

I really can't answer that. Ironically, the ones we have been seeing have been babied. The one with the broken rockers had just over 200 hours. 125 of those were at idle. There was only 1.2 hours over 4000 rpm. (.7 hrs 4000-4500, .4 hrs. 4500-5000 and .1 hrs. 5000+) There shouldn't have been a failure with that little bit of running. The one that broke the rod had even less time. It's rpm history was very similar to the above. It just so happened that it cut loose when the owner took it to 5000 rpm on one of those rare occasions. That's why it made such a mess.

There is no rhyme or reason to the failures. From what I've seen, run time and rpm amount has nothing to do with it. I can tell you that the valve springs absolutely suck ass. They are too weak and loss pressure too quickly. Both the headers and tails need to be looked at on a regular basis. Other than that, I can't tell you why they fail.
Eddie

thx for the info Young Performance.... I think i am going to buy a shiny new cedar strip canoe!!! I can't afford to buy another boat.. then drop another 25 K to rebuild engines.... and with my luck if I didn't touch them it would have only been a bad timing chain.... LOL

Oh and where should I look for that bearing?? cant seem to find that muffler:funnypost:

That would be mine. I hope you thought of changing out my fresh water muffler bearing for one that is salt water compatible. . I didn't see it on the bill :)

That was yours. I threw the muffler bearing in for free. I do that for all of my favorite customers. Consider it an early Christmas present.
Hope you guys are doing well. If I don't talk to you before Christmas, you and the family have a wonderful Christmas and great and prosperous New Year.
Eddie

Thanks Eddie, you guys have a Merry Christmas as well.

As someone who is searching for an entry-level cat with 525EFIs as the next boat, I greatly appreciate everyone's posts with info in this thread. Thank you guys!

Great first hand info here!!! I find it interesting that 20 years ago merc was building 500 bulldogs, 525sc, 600sc's, and 800sc engines that went longer between rebuilds than these 525efi's. Kinda sad actually.

The 120psi of seat pressure baffles me. The camshaft isn't exactly what I would call mild, from a lift and duration standpoint.

Eddie, have you seen signs of the lifters lofting off the cam lobes? Maybe the valvetrain after some time is just becoming greatly unstable .

Understand that I do not use my 525 fountain in salt water. That's what my outboard boat is for!! I also keep the 525s sprayed with wd40 or red corrosion x. They have no corrosion that I can see.

I only race my 525 at WOT. I don't recreational my boat so my opinion is based on WOT time only. I have never blown up a 500 carb,500 EFI or a 525 EFI. We run them hard for at least 125 hours at WOT. At that point we will change the springs and we have never seen a signal MPH gain. I think the 525 is a fantastic platform for the average boater to step it up compared to a stock set up. Remember when you do a rebuild at merc. for that $12K they give you all your parts back which includes the old set of heads loaded with all the parts. IMO the failures are based on age and use of the product. Change your oil, test your headers and pin the throttle is my suggestion. Run it till it blows and you may be shocked just how long it last.
Is there anyone out there with more than 400-500 hours on a 525?

I heard if your Mercury Racing power has the gold color rockers change them at 200 hours or before.

Awesome post!

Springs and rockets are the weak link, the Crane rockets arms Merc is using now is junk. Like Eddie meantioned in his post, you have to go and chase the needle bearing though the motor. The motor builders I have spoke to all say the same thing, and are staying away from them.