Looking at a 99' 38ZX with 525sc's with 35 hours on them. I don't know anything about the engines, and was wondering if someone could shed some light on them for me. Pros, cons, and reliability issues. Also expected performance in a 11500lb boat.
Thanks

IMHO, one of mercs better engines. 454, 177 blower, 5 lbs of boost. The carb they use tends to run rich at idle though. For a blower motor, they are very reliable. Will last a long time if you dont run them WFO all the time. Cruise a low (1-2psi) boost levels and the engines are hardly working.
Downside; heavy boat, hi torque motor, with a bravo I? drive. The drive is going to be the weak point. Expect upper, coupler, and gimbal ring problems.
Gary

always heard good things about the 525

my setup is very similar (not merc) and has been running pretty well so far.

Thanks guys, I have a fear of the stock Bravo 1 myself. I am thinking of using some TCM upgrades to have a more reliable setup. Any other drive suggestions?

Thanks again

as long as you aren't really beating on the drives they aren't going to pop right away. And if they do stock b1s are dirt cheap now because of all the new upgraded drives.

Gary's input I think is right on the button about Bravo's behing your week link.

I boat with a gentelmen every weekend that has a Scarab 29 with a 525SC, it has 260hrs over 4 summers and the thing has run like a swiss clock ever since he baught it new. He takes excellent care of it and only ocasionaly runs it WOT. The only drawback is that he needs to run 93 OCT in it, and sometimes it is hard to find on the water.

Hey Lonestar...

I have been using three of them in an old 12Klb Scarab for the past four years and have found them to be nearly flawless... I have not had any problem idle wise with the Dominators but sloshing around on a hook seems to dump the bowls after a time for a hard black start... The drives have been no problem either, however, I don't fly the boat, intentionally that is... Just my $.02 but compared to what I read about the EFI folks I am quite happy with the performance... Guess the best thing is being able to adjust and change parts...

Thanks, Karl

I rode in a 1997 42' Fountain "Reggie Signature" with triple 525sc's in it this summer and with 7 guy's a full load of fuel and on flat water it ran 80mph....motors ran smooth and had lot's of torque....my .02.....Fred

I think you will be fine with 91 octane in those engines, merc has backed down on the octane rating on the 575 from 92 to 91 and I believe the book on the 525 also required 92.

A call to merc would confirm that, but am am 90% sure it is correct.

HP 525SC


Mercury HP 525SC Specifications


Propshaft Horsepower: 490/365
Full Throttle RPM Range: 4800-5200
Displacement (CID/CC): 454/7.4
Bore (inches/mm): 4.25/107.9
Stroke (in.)/(mm): 4.00/101.5
Compression Ratio: 7.5:1
Cylinders: V-8
Fuel Requirements: 92 Posted Octane
Drive Unit: Bravo One
Gear Ratio (RH or LH): 1.36:1 or 1.50:1
Length (inches/cm): 47.7/121
Width (inches/cm): 32.75/83
Height (inches/cm): 28/72
Depth: 9-5/8 in. single 13-3/8 in. side by side
Weight (lbs./kg) - Bravo One: 1470/668
Warranty: 1 Year

What is the stock carb on the 525SC?