intouch1

just sold my Donzi 27 ZR 496HO yesterday and am about to place an order for a Donzi 35 ZR....

i am having difficulties deciding between going for twin 496HO's or twin 525EFI's...

i surely think 525 is the way to go. however, i am a bit worried about heavy maintenance schedules of the 525's.

the black motors require oil and filter changes every 100 hours whereas the blue ones every 25-30...

all comments appreciated....

also if i decide for the 496's should i go with xr drives or is the bravo x enough ?

last issue if XR's should i order ITS or is external hydraulic steering better ?

Wild Card 09

Iīve run both motors, hard and fast, in my 25OL. They both have been clean, reliable and free of problems. One of them just has about 130 hp more than the other.

However, in my opinion, if you run a 496 any where near its maximum potential, you should be changing the oil just as often as with the 525.

The blue motor is only running at 75% of its potential when delivering the black motorīs maximum. The 525 is an amazing motor, and has sold me on the blue motor philosophy.

In view of the fact that the blue motor runs better, all the way to itīs 5350 revlimiter, whereas the 496 makes you feel like it doesnīt really want to run past 4900, I get the feeling that a recreational used 525 will probably outlive a 496 in the same application.

Go blue if you can cover the extra cost. Youīll enjoy it that much more out on the water, and at the dock....and the rest you get back at resale.

monstaaa

525's are no more needy than the 496. i might say the 496 need more attention due to the mesh air screen elelment . collects salt chrystals. they then pass thru and clog up the iac filter or trsvel further down and clog the iac itself. will deffineately need plenty of oil service as does the 525, but for what ever reason the 496 seams to turn the oil black very soon as in to comparison of the 525.
big benefet is the extended warranty on the 496. cant beat that 5 years of comfort.
either way your getting merc power. so sit back hold it down. and enjoy the reliability of merc power.

LAKESIDE RESTORATIONS

I would have no fear of the 525's & service.. Yes you will pay a little more over the long run, but you have more power than the 496 too.. The 525hp (efi) is really not an engine that needs constant tuning like the older stuff.. The biggest thing is head service check at the first interval.. A good machine shop can upgrade the springs so you can go longer next time.. Jamie / Lakeside Restorations...

intouch1

dear jamie...thank you for your input. our local mercury dealer/agent is not really certified for servcing the Mercury Racing line of engines and therefore I would certainly not want him to come near the heads of the engines.

Do the valve springs really need tightening on the 525efi's vs the 496HO's ?

i had read about that somewhere but the current owners manual of the 525's has no mention of it.....

LAKESIDE RESTORATIONS

No problem.. And I do understand your concern..

As far as the exact service intervals on the current 525, I don't recall it specifically in my head at the moment. I believe the earlier blue stuff was something like 250-300 hrs.. I believe it is still the same deal, Unless merc made a change that I am currently forgetting about.. I dont know that you will actually find that in the manual anywhere per say, but it has been something that many have known about for a while now..

The valves / springs don't actually get tightened. They get checked for the proper amount of tension & to see if any are broken. The stock merc springs seem to be on the soft side and need replacing sooner than others.. Most places replace them with better springs when doing a head inspection/service.. Jamie / Lakeside Restorations

crb76

big benefet is the extended warranty on the 496. cant beat that 5 years of comfort.


You can get 4 year extended on the 525EFI.

I have it and love the package.

monstaaa

not an original mercury offering if i'm not mistaken.

Wild Card 09

I was told by Merc Racing that the valve spring issue was only on the HP500 motor, and never an issue on the 525EFi. It isnīt in the factory workshop manual, and just about everything else is in there that should be refreshed.
The only bad news issue that Iīve heard about on the 525 is early ones having problems with a faulty series of CMI headers.

A definite plus on the 525 is that it doesnīt deposit anything like as much soot on the transom as my 496 did after a hard run.

monstaaa

the soot wild is refering to is part of the same issue i was speeking of.