First run today!!!!
 

First time out on my 28 with the 525-last season had the 496HO--Love it!! 2 Questions, I eliminated the silent choice when I removed the 496-what are my options to quiet it down once in a while? Do them bolt on external mufflers work? What RPM's should I run at was doing 4900 BUT GPS was not working!!!

congrats, hope to splash soon!!!cosmic had a 28 with a 525, he'll probably be in here soon

my 525 ran 4951 rpms with 28 bravo 4 blade. I had corsa full time mufflers and Pat always told me that they choked the motor but I tried it without the mufflers and didn't see a difference. I loved the sound of them. Glad to see you got it out:cool:

merc 525,s should be run up to 5400 rpm or some where real close . 5200 or better. the best power is over 5000rpm .
if your running a stock prop at 4900 rpm you should try a labed one and if you can pick up 300 rpm and get the motor to 5200 rpm you will be in good shape or get a smaller prop.
i was runing my boat with a 28 pitch for 5 month's "thats what it had when i bought it" and just threw on a pair of 26 pitch and the get up and go is real nice and mid range punch is there . i was only able to get 4900 rpm out of here now i can get it up to 5300 rpms. and the motor's sound so much better . there's no lug . they whine up nice and easy .
good luck
mike

There is a Captains Call for 525's.

Speed?
 

Cosmic what was the fastest your boat would run?

He wouldn't know cause he was SCARED of the throttle and he wasn't able to reach it when he had the lap top on the dash and stirring up chit on OSO.:evilb:

Thats funny
 

Nice!

that is funny:evilb: 2267 and counting, but look!!! I don't have to worry about the throttle anymore so I should be able to get that # WAY up there now. besides don't you have some motors you should be working on?:D

Nope cause I have someone that knows what there doing instead of me working on them.I only know how to kill them not work on them.:D

I told you they drink motor oil, not RB & Vodka. :drink:

I forgot again.Sorry.:D

Risky, WOW is all I can say:cool: Are you running open exhaust? Must be loud as hell

mikebrls is dead on. The 525EFI makes optimum horse power (540-550HP) at 5380 RPM. If you look at the dyno sheets anything less than 5200 you are running less than 500HP. FYI-The rev limiter is set at 5415-5425.

??
 

So how do I get the RPM up to 5300 from 4900? I am running a 26 pitch 4 blade that throttle up cupped slightly. Cosmic I am running open pipes and it very loud! Thinking of mufflers that I can remove. Never really cared for silent choice. Unless someone can explain captains call-isn't that silent choice?

you would need to talk to a prop place about taking a half to one ptich out of prop and have a good race lab done that will get you 300+ rpm .
- one pitch = 200 rpm + 300 for the lab will get 500rpm total and put you rite at 5400 rpm :)
good luck let us now how it run's.
or if you no someone with a 24 pitch prop just to try out it will give you a good ballpark #.
the 24 will scrubb some speed . but if you tweek your 26 prop it will run like a 24 but give you more speed :)

to get the rpm's up, run a smaller prop and see if you hit the limiters.
the key is, just keep trying till you find the right one.

I may be wrong here but wasn't there a issue with getting enough air into a 28 with a 525? I can't see how a 26 would be too much prop. I would even think a labbed 28 would be possible.

prop
 

Pat said 26 four blade or labbed 28-so if a 26 is at 4900-how does a 28 labbed get me additional Rpm? The 26 I am running is cupped slightly and worked by throttle up-is this a cause for low RPM? The speed is there but the rpm is off if that makes sense..I am hoping to have the gps speedo fixed soon the handheld I think estimated high I think?

That is correct at sea level and heavy saltwater. Fresh water and Altitude will kill your RPM. If you lab a 4 blade you will get about 300 RPM. A five blade will give you between 400-500 increases in RPM.

If you are running fresh water you will need to remove the cup and lab the 26 to reach the RPM you are looking for. The boat rides much deeper in fresh water than in salt.
Prop it for 5400 and you will not see that with a normal load, fuel and air.
Jim

every boat is a bit difrent . depending on what you have in the boat and weight of boat "full gas tank or very litle gas will make a few 100rpm difrence . also how you trimm the boat do you run it trimmed out to the moon are your tab's all the way up,extension box, all this will make a diffrence.
if you cant push a 26 ptich prop past 4900 rpm a lab 28 will be no good . a lab 28 will be almost like running a stock 26 maybe a 100rpm less this will bring you to 4800rpm again no good. your best bet is to have the 26 prop tweeked. for the best performance of your boat .
good luck
mike

You want the engine running in its powerband.
your max rpm should be right under where the max hp rpm is.

I think its best to test w/ a good standard baseline prop.
Get a 26 B1 and see how she runs... and you gotta run it trimmed properly.
If you may think its not getting enough air, take the engine hatch off and run it. Thats an easy way to check it out.

I'm running the HPI 9049 clamp-ons on my 525, you definitely want to raise your RPM's as others have said. I would shoot for about 5350 with alight load and cool temps! Check out the March 2005 issue of Hot Boat for a muffler comparison test. What kind of speeds are you seeing GPS? Steve You don't have to remove the engine hatch, just raise it a few inches at speed, I doubt that it'll matter, been there done that!

I'm not the prop expert like Clark:eek: :D but I would take some of the cup out along with a bit of pitch. I had a 26 cupped to try and get some bow rise out of the boat and it took RPM away and didn't help with bow rise. But like I said....I'm no prop expert:D Trial and error......

Why isn't anyone using 3 blades? I am kind of new to this, but I noticed a 200 or so rpm increase as well as more top end on my existing 27'. Yes I know the boat didn't get up out of the water quite as fast, but it was really minimal and I thought Mid range was actually better.

a 3 blade will be faster . but it does not have as much bite in the water for control. on a twinn engine set up you mite be able to get a way with it mostly on cat's

no, you dont have to take the engine hatch off, but make sure the wind doesn't start to lift it up from running 70+. thats alot of air pressure pushing on the hatch.
Again... trial and error.

I didn't notice any control issues, but we shall see soon as it sounds like I will be trying to prop a boat real soon too.

Gps fixed !
 

Hit 5100 rpm's today with 2 people and 3/4 tank gas--speed was less than expected 73 on GPS speedo 78 on hand-held the other day did not trust that though. So am I to expect at 5300-5400 75-76 MPH? I am going to run smaller prop to see if I hit rev limiter-than I will try to remove cupping on my 26 4- blade-then I guess it is a 28 lab I will try. Thanks for all the help it is much appreciated... vic



BY THE WAY WELCOME TO THE A/T WORLD OF BOATING TOM--

Offshore Tom, I cannot use a 3 blade prop on my 25....x Dimension set up on the aggresive side. I tried a 25 3 blade and it took forever to plane out and I lost a ton of top end. Tried a Hydromotive 4 blade and the stern lift killed me, Off that came!!!:D Good luck!!:cool:

Risky, Wanna borrow my tweaked 26 4 blade? My boat is coming out tomorrow and coming home for some upgrades.....nothing major....except steering.:D

Hey R, what kind of steering are you going with?....not that I can afford any more this year:cool:

Vic, Sounds like you are getting it. Why do you want to be hitting the limiter? You have got good speed and hopefully reliabilty I would be happy. But maybe I just babied mine to much.

Risky

I have did a comparison last year on that 26 I sold you and a labbed 28. You are going to have a little less RPM with the labbed 28 (50-100 less) and gain about 2-3mph. I would go with labbing the 26. Call Julie at Throttle Up, give her all your numbers and send the prop. They will get it right.

Be sure and write down all GPS speeds, RPM's, weight, etc and keep that data as it will come in handy in the future.

http://www.rbbi.com/folders/prop/propcalc.htm

I would shoot for 5250 -5300 RPM's on that motor if it is stock.

Camp, Dual Ram Imco external add on. My brother is a dealer and I get a good deal. Gonna do the add on this summer and hopefully finish it off this winter when I have mo money.:D

Thanks
 

R-Addiction I appreciate the offer-I will let you know. I was reading these posts and was under the impression max HP was at 5300-5400-so if I am at 5100, 300 more rpm would be OK- I will talk to throttle up about the prop- don't want to be greedy and do not want to beat up the engine might just leave alone and enjoy. Thanks poker and run I will call her. Thanks for the prop. Boat ran 63 last year so I did gain 10 MPH. I only ran the boat 2 times I will run a couple more and see what numbers I get.

risky, I thought you had a 500hp in there before? You picked up 10 mph with a 525? WOW now thats impressive:cool:

not 500hp
 

496HO to a 525EFI so 425 hp to 525--gps speedo best w/496 HO was 62/63--gps today was 72/73.

10 mph with 100 hp is awesome!!!