engine rpm

wakeskater64 01-13-2006, 6:14 PM

i'm looking at buying a 96 sport nautique i was reading the manual and it says 3600rpm constant and 4400rpm intermitant so the boat is supposed to 45mph top speed, is that at 4400rpm and how long can i keep it on that rpm,

(99_slaunch) · (99_slaunch) **Join Date: Oct 2005** 01-13-2006, 8:13 PM

4400 is a lot of rpm. That motor is done at 5000 or 5500 rpm. You don't want to run it at a high rpm for a long time. What are you going to do with the boat wakeboard or ski?

(mikeski) · (mikeski) **Join Date: Aug 2003** 01-14-2006, 9:19 AM

Andy,

For cruising it's best to stay under 3500rpm or you will start sacraficing motor life. Are you a barefooter? Barefooting is the only reason I typically run my boat flat out for any length of time. I kind of cringe when I see guys running flat out to get to their riding spots. Crank up the tunes and make a pleasant ride at 30mph, your crew will be happier in the long run.

(99_slaunch) · (99_slaunch) **Join Date: Oct 2005** 01-14-2006, 12:10 PM

I agree mikeski I run mine at 3000 to get to my spots.

wakeskater64 01-14-2006, 12:52 PM

Cheers, i only wakeboard but some spots are quite far but i'll stick to 3000rpm to save me some cash.

(mbrown) · (mbrown) **Join Date: May 2005** 01-15-2006, 10:28 AM

Indmar recommends intervals of WOT (5200 rpm)after break-in but before 100 hours to further enhance cylinder glazing and ring seating. This will cause any oil consumption to stop and decrease carbon build up on new rings.
(I called the 1-800 number)

(99_slaunch) · (99_slaunch) **Join Date: Oct 2005** 01-15-2006, 10:53 AM

The harder you break it in the harder they run!! After cam break-in it's either gonna go or blow.

(ebone66) · (ebone66) **Join Date: Dec 2005** 01-16-2006, 10:30 AM

Matt, Run that by me again... I'm getting a new boat that has an indmar. How should I break the motor in?

(mbrown) · (mbrown) **Join Date: May 2005** 01-21-2006, 12:35 PM

no more than 2000 for the first hour
3000 for the next and 4000 for the next 5 hrs (change oil soon).
Vary the RPMs, start and stop a lot, not hard. Then pull and run the hell out of it. You have to hit WOT for several minutes with each use to really glaze those cylinders.

(bob) · (bob) **Join Date: Feb 2001** 01-23-2006, 11:59 AM

So what your saying is you want the cylinder wall to glaze???? http://www.hastingsmfg.com/Service%20Tips/cylinder_deglazing.htm

Allowing to much heat to build up at the ring to cylinder wall interface will cause the lubricating oil that is present to break down and glaze the cylinder wall surface. This glaze will prevent any further seating of the piston rings. If glazing is allowed to happen break in will never occur.
From here:http://www.mattituck.com/new/articles/engbrkin.htm

(mbrown) · (mbrown) **Join Date: May 2005** 01-23-2006, 6:02 PM

Bob,
That's why they (the Indmar Technicians) don't tell you to run an entire tank of fuel at WOT.
There is a happy medium when "polishing" (glazing)the cylinders. They need to reach a consistent polish so that the rings seat. The engine does not need to be run until white hot (like a race car) for this to happen. If you do not open it up at all during the first 10 to 100 hours, your rings will collect coke and will not expand to seat within the cylinders.

This problem has occurred within some of the GM marinized motors and to combat this GM has come out with a product that is poured into the cylinders to dissolve the deposits, then removed to assist in ring seating. Several Techs have said this is mostly done on marine engines that have been babied too much during break in.

I wish I could add a link too! Just call the 1-800 number for Indmar.