Mercury Racing 525 EFI, 390 hrs

[jimbo5o]

Good day,
I don't post much here, but respect the opinions of most members. Have a boat question for the experts here. I'm looking at a nice boat with a 525 with 390 hrs, I understand that the valvetrain should be refreshed at around 250 hrs. This one has never been touched, should I steer clear? Pull the trigger and have the valvetrain done? what kind of life should be left in this motor? Not wanting to spend 50K on a boat and immediately have to drop another 5-10K on engine work before the boat ever gets wet.
Thanks in advance,
Jim

 

[Blackmagic94]

Have a mechanic perform a leak down and compression test prior to purchase.



Most likely the compression is good. So may just need to refresh the heads. Valve job and new springs. 500-750 at a machine shop plus the labor to r&r the heads and exhaust.

 

[C08H18]

I’m in a similar position and asked a few shops. Feedback is to do a top end refresh at 300 hours ($2800-$3000) and motor should be good till 600+ hours. I would check compression before purchasing.


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[Runs2rch]

I’m in a similar position and asked a few shops. Feedback is to do a top end refresh at 300 hours ($2800-$3000) and motor should be good till 600+ hours. I would check compression before purchasing.


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Should go longer than 600hrs if not beaten.

 

[C08H18]

Should go longer than 600hrs if not beaten.

The shops recommended top end should be refreshed every 300. Not implying the motor is done at 600. I have 800 hrs on ski boat and it shows no wear.


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[H20 Toie]

Great motors, both my Cigarette and Formula had 525's, on both of them at 400 hrs i had the top ends done, everything was great except for weak valve springs.
So i would say yes buy it, do the top ends and enjoy lots of time with it,
i would be more concerned about the headers unless it has stainless marine headers, the CMI headers are fantastic for leaking after a couple of years and that can take out your motor.

 

[ToMorrow44]

Great motors, both my Cigarette and Formula had 525's, on both of them at 400 hrs i had the top ends done, everything was great except for weak valve springs.
So i would say yes buy it, do the top ends and enjoy lots of time with it,
i would be more concerned about the headers unless it has stainless marine headers, the CMI headers are fantastic for leaking after a couple of years and that can take out your motor.

I was thinking the same thing, the headers would be more concerning at those hours. It still needs the top end done and the number I always heard was ~$3k which would be good peace of mind regardless.

 

[guest hs]

Valve job springs and new lifters should be good to go buy I have seen many go way past 400 hours I really feel it depends on how it has been used. A race application 300 yes

 

[HB2Havasu]

You could always ask the seller to drop the price to cover the scheduled maintenance that hasn’t been performed.

Before you do that I would take it to a good mechanic and have them do a leak down / compression test, hook the engine up to their computer and scan hours / rpms etc, also have them do a drive check. Those can get expensive to repair as well.

 

[guest hs]

This is good advice. Get the run history pulled from it and that will tell you a lot. I scanned a guys boat last week 496 HO it 325 hours of run time 201 of it was at idle speed probably a channel cruiser. If you found that the boat your are purchasing was run like this I would buy it with no reserve what so ever. You could easily get 100-200 more hours out of the top end depending on how you drive it and maintenance of course.