kachinapowerboats

Hello Guys,

Im just curious if anyone else has had this problem with the 700sci ? One of our customers chose this engine package with the nxt drive in one of our 30's and is complaining big time about the performance out of the hole! He claims that he can go WO throttle and the engine will not even rev for about 2 seconds, after that he says it revs very slow for about another 3 or so seconds and then it comes alive and is a monster. He says Mercury claims that there is a program in the computer that will not allow the motor to apply all of the horsepower from a dead standstill! He loves the boat but hates the performance out of the whole, any ideas how to correct the problem??

Beak Boater

Have a pair of 700 SCi;s in a 38 Fountain. It does the same thing. I was told that it is because I am running such big pitch props. 16.5x39. Mine has to go into boost to brake the props loose to spin them to get on plane. We are also running 1.5 gears in #6 dry sump drives. You have to give it full throttle to get it to go into boost. Their is a lag time before it does. Have also tried to get the rpms off idle bring them up to about 1000,1200 then hit the throttle. It helps a little but their still is a lag time.

QWKRN U

wonderful drive by wire technology. Its the tourque management software taking over. Once some of the tuners figure out how to crack the ecm's Id expect him to be very happy with those.

kachinapowerboats

I have to agree that it is the torque management system. A Merc racing engineer came out to assist and certify my guys in the installation and he deemed it normal. Bottom line is the customer is bummed about it. He loves his new boat but claims he regrets the power train decision he made. We are running a 5 blade maximus , cnat recall the pitch at the moment but it is the one that performed the best overall. My customer tried a 4 Blade Bravo and he says it helped a little out of the hole but killed his top end. We have done 720's from Teague and they performed awesome! The 700sci is a beast and a hell of a motor but I think Merc needs to Torque management issue soon! P.S. The reason my customer chose the 700 is becuase he lives in Lake Tahoe and is at 6800 feet. The one cool thing is he only lost 2mph with the altitude chane from Phoenix to Tahoe!

kachinapowerboats

I have another customer running twin 975's in one of our 34's and he is running about 116mph. Believe it or not he decided to go with XR Drives. He says the #6's rob way to much HP so they may be part of the problem along with the big props?

Wild Card 09

I´m not in the same power league as you guys, but my N/A 2006 525EFi in my 80 mph Outlaw feels exactly the same when I run a Maximus prop, and even with the labbed 28" Bravo, it seems like it takes a few seconds until things really come alive. I figured it is the nature of the camshaft.
However, in retrospect, it could be electronics protecting the drive from abuse. Not such an issue with my power package through an XR, but blower motors can give their drives hell.
The first time I rode in a 100+ mph boat, I was surprised how much work it was to get the thing up on plane. There really are no free lunches.......

Beak Boater

I think the lag is just part of the torque management system, I wonder what they are protecting, the transmission, or the NXT drive. The 6's may take a little more horsepower to turn, but Ill take the reliability. The boat still runs 114 mph with twin 700's.

Beak Boater

Thats why we left when we did If we stayed it would have been really ugly, how was Worx band? We are not running from a standing start. Besides you know how hard that would be on those gearcases of yours.......oh thats right you already had problems.

thunderusone

I agree. Does anyone know which tranny they are using? I thought I read somewhere it was a Bam......which should take the 700 all day long hard out of the hole. Surely to god the NXT can take that?? The torque management would be great to have on some big hp bravo applications....especially if it is controlling the boost bypass valve on the Lysholms. The big bam tranny works great to 1200hp......you can blow one at will at 1400hp. And baby it in reverse. We had the motors set on 1200hp trying to get a 43nt off the trailer in a shallow ramp. Gigged it.....and KABOOM!!

Beak Boater

Its not a transmission like Hueber, or Bam. The NXT transmission is a new piece. Im told it is a bigger version of the cone clutch set up in a bravo drive. Thats probably over simplified, but its not that big, and it runs Mercury Hi Pro. gear oil in it.