Need Help Quick!!
 

Ok everyone, I need some help here. As many of you know, I have been redoing my engines over the winter. What I did was take my stock 525SC’s and replaced the blowers, carbs, pulleys, belts, etc. Prior to this I was running 88-90 with standard Bravo’s on my single step 35’ Fountain. After the new 420 mega-blowers, new carbs, belts, pulleys and nose cones on the drives were added, I’ve lost 3-5 mph. Obviously we thought it was the drives or props so we tried a 26, 28 (original), 30, and 32 pitch prop with little to no difference in any of them. We then tried 2” shorter drives because we could not get the props to blow-out getting on plane like they had been, still no change and still lower speeds. We got anywhere from 5400-6000rpm’s with then props, but nothing helped. Finally, we thought maybe the engines had a compression issue or leak, but we tested them both and they were perfect. The only thing we can think of is that we aren’t getting the horsepower we should. If so, how’s that possible? What could possibly be mismatched that would be causing this problem? Should I spend the money to have them dynoed, then find out it isn't producing the horsepower, but not know where the problem is or find out they are producing more with lower speeds? Everyone working on this is completely frustrated!! Help!!!!!!!

The dyno will eliminate the HP question and show where you should running RPM wise, however if it is pulling strong you my want to look at the nose cones, maybe try a stock set. I have heard of certain ones that have "lost" speed when adding cones. Just a thought.

We thought of that, but we tried the shorties and they did the same thing............

What did you change as far as the carbs ? Are they boost ref, and does the motor seem strong or does it lay down ?

Carbs we went to dual 850cfm. The motors run amazing, idle great and sound perfect...........

Who built the motor's??? I've had nearly the same problem with Motor builders in Kansas City myself!!! The problem being is that they might be great at building a Big Block for the Drag Strip but don't know the right combonations for Boat's (i.e. Offshore Boat's - not small jet boat's)

What cams are you running??

I'd add a Superchiller to cool the fuel, when you get a chance. Heck I've heard of people adding a "chiller" to a stock 525 and getting AWESOME results!!

They were stock 525's and the guys at Advanced Marine jjust added the new parts. It runs great.........

Advanced Marine in St. Louis???

No, at LOTO. They do work with the Bacardi Team........

You are not making as much Hp as before. Get those motors hooked up to a dyno and see.