525 sc's with 290 hours
 

Hello Guy's,I have a set of 525 sc's that will have close to 300 hours by this seasons end that have never been apart. I was wondering what kind of maintenance that I need to look at over the Winter to ensure that they continue to be trouble free except for the obvious impellars,plugs,fuel filters,oil change,drive inspection,etc.The engines run great and use no oil between my 30 hour oil changes and hold recommended boost @5000 rpm.The only issue ive been having lately is the port engine hesitates alittle when throttling up from idle and has backfired a couple of times and died.I believe thats in the carb and will look at having it rebuilt this Winter.Ive been told by different people to do leak down test on each cylinder of both engines,Change valve springs,Have blowers gone through,etc.I don't want to spend the $$$ if don't have to but i want to continue to have trouble free running time.Im not hard on my engines and rarely run over 4000 rpm's!!Your feedback in this matter would be greatly appreciated.Thanks Hank36

I know a guy at my rack storage marina that says he has 700 hours on his and they never been apart, They are in a 38 S.C. Fountain.

525 sc's
 

WOW!!!!Thanks for the reply Johnny B Good.

Have you ever changed the blower gear oil?

525sc's
 

Yes,I change the blower oil every 30 hours when I do my engines.Hank36

Sounds like you're doing the same maint intervals that I did. I went throught the top end on mine at 340hrs, but ONLY because the Gil exhaust cracked and pitted an exhaust valve. I also added a roller cam for some more hp. The stock valve springs don't have issues and should be fine. Its only a .530/.551 lift flat tappet cam.

Mine had 475hrs when I sold the boat and over 500hrs when the new owner pulled it for bigger power. The blower was never rebuilt. Most people had to get them rebuilt at 200-300hrs. I changed the lube frequently(25-30hrs) and thats probably why it was fine. Make sure you are changing both the front and rear lube. They are separate. You could send the blowers in to the Blower Shop to be checked, but they should be fine.

Also, make sure to change the fuel pump lube regularly. Mine would become fuel diluted. I changed it about every other oil change.

The hesitation off idle is probably just the accelerator pump.

A leak down won't hurt, but as long as everything is running fine and you haven't lost any rpm, you probably don't need it. Also, you're not using any oil so the cylinders should be fine. Mine used a quart every 15-20hrs.

Do you have the Merc/Gil exhaust or CMI's??? If Gils, I would pull the risers and check the tops of the manifolds where the cylinder dividers are. Look for white crack lines. Thats where mine cracked.

Has the boat ever seen salt???? If so, I would pull the intake manifolds and inspect the water passages. Mine saw some salt before I bought it and the water passages where they meet the heads where in bad shape and had to be welded.

I have posted a lot of 525SC info over the past years. If you do an advanced search with my screen name and 525SC you'll find a lot of info.

Your welcome, but like everything there is always exceptions to the rule, I do know this guy with the Fountain is very meticulous with maintance and doesnt beat the crap out of his boat.

525sc's 300 hours
 

Thanks for the info Griff.Mine came factory with CMI Headers and corsa silent choice which is good.I just got back from a 3 day weekend at Ky Lake and my boat ran great except for that little bit of hesitation that i mentioned on the port engine with the carb.I put 2 new fuel pumps on this winter due to one leaking throught to the inspection tube from the diapram.Ive got 8 lbs of fuel pressure and my boost on both engines is the same as is r.p.m.s.Did your engines turn over 5,000 at w.o.t?That's all mine will turn with 28 labbed bravo 1's on a outlaw v bottom hull.My manual said they will turn 5200 just wondering.I don't ever run them that hard anyway just curious.Thanks Hank36

A few things come to mind on your performance concerns. Typically, a manufacturer will give numbers under ideal, hard to duplicate, conditions. A waxed hull, near empty fuel tank, cool temps at or near sea level with blue printed engines and drives is not what you have. You should be proud you're getting what you have. Few people would justify the expense and inconvenience of rebuilding with the "hope" of gaining that 200 rpm. If you want to upgrade, that's different.

mr.clog
 

I wasn't looking to rebuild or anything like that to get 200 r.p.m's.Just comparing to a fellow 525 sc owner who seemed to have alot of knowledge about the style of engines and wanted to make sure that i was doing the proper preventive maintenance on my Boat.Thanks hank36

I spun mine at 5100 stock and then spun it up 5300 after a cam upgrade. I had the prop tweaked to do it. You could easily install smaller top pullies and pick up 100rpms or so. You could aslo send the props in to BBlades and tell him that you are looking for another 200rpms.

you are probably sitting about right at 5000
for top speed. and a good cruise

i run 5100 in a 336 formula with 24 4 baldes and 1.36 gears
50mph cruise at 3200 rpm

you could lab the props as griff said and get a little more speed, but tell them you don't want to loose any cruise or you just might after they thin the blades. I might split the difference and try to get 100 rpm out of labbing.

before anything, make sure you cant get more rpm already riding alone, trimmed out, cool air conditions, a little chop, and low fuel. ( sounds like a good last fall run, pumping the stabil through the system :)

I ahve 400 hrs on my 525sc's

525 sc's
 

Hello Rambunctious.Have you done any internal work to engines?Blowers pulled and rebuilt,Valve springs,ect?

valve springs have not been done
the blowers were done by "the blower shop" in california for the previous owner at 250 hrs

I was going to do them last winter but only ran 20 teh previous summer.
I only ran about 15 -20 hours this year as well, but I plan to redo the blower bearings just for preventative maintenance
these 177 blowers on 525sc's do not have rebuildable seals like larger blowers.

this is only the second summer with this boat for me , but the previous owner had all the records of maintenance and changed ALL fluids every season ( also very short seasons for him)

So I am just going to do the same.
both engines run perfect right now,
I hope to keep it that way.

I think the blower rebuilds are about $200 each??

Ramb

I think rebuilds are about $400 plus parts.

What are rebuildable seals?

what I meant was these wieand 177's that are on all of our 525sc's do not have teflon seals on the rotors for sealing to the housing like some other larger blowers designs.

that is one reason why bearing maintenance is important with these, ( to maintain the proper clearance)
But also why rebuilds are not terribly expensive.

this is what I have been told or learned. I have yet to do the rebuilds on mine as the boat is still quite new to me.

Ramb

Ramb
 

Thanks for all of the info Guy's.Ive been out of Town.I guess im going to send my blowers off this winter,Have my port carb rebuilt and do a leak down on both engines to be safe and be looking forward to Summer again.Thanks Hank36