'99 SN WOT: RPM & Speed below normal

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   Based on the replies I received a few weeks ago, I should be producing higher RPM and top speed with my set-up than I am. Do y'all have any suggestions as to what things I should investigate? Does the ECM have a governor?

More on my boat:
1999 Ski Nautique. Pro Boss GT-40, fuel injected.
I had the engine rebuilt in early 2013 by some quality guys. Has 130 hours on it now. Fuel injectors, cap, rotor, throttle body also new at rebuild.

The lake where I ski is approximately 2800' above Sea Level near St. George, Utah (Quail Reservoir)
Acme 654 propeller.

I did a boat test the other day. I was the only person on board, very little gear, no back seat. or back seat backrest.
WOT yields 41 mph on both my perfect pass GPS speedo AND on my iPhone GPS speedometer. Max RPM at WOT is 4400. Lake was flat.

Engine to drive shaft alignment is correct within 0.003.
Driveshaft passes the .003 trueness test on both sides of the strut.
Propeller has about 300 hours on it. No knicks. If you take it off the boat and lay it flat, it does not rock when you press on any blade face up or face down.

Throttle cable has full travel from idle to butterfly. I took off flame arrestor and visually looked at the position of the butterfly when I moved the driver's throttle arm.

Thank you for reading and your input,
Dave 

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utahdave Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: April-06-2013 Location: Washington, UT Status: Offline Points: 51	Post Options Post Reply Quote utahdave Report Post Thanks(0) Quote Reply Topic: '99 SN WOT: RPM & Speed below normal Posted: August-02-2015 at 9:51pm
	Based on the replies I received a few weeks ago, I should be producing higher RPM and top speed with my set-up than I am. Do y'all have any suggestions as to what things I should investigate? Does the ECM have a governor? More on my boat: 1999 Ski Nautique. Pro Boss GT-40, fuel injected. I had the engine rebuilt in early 2013 by some quality guys. Has 130 hours on it now. Fuel injectors, cap, rotor, throttle body also new at rebuild. The lake where I ski is approximately 2800' above Sea Level near St. George, Utah (Quail Reservoir) Acme 654 propeller. I did a boat test the other day. I was the only person on board, very little gear, no back seat. or back seat backrest. WOT yields 41 mph on both my perfect pass GPS speedo AND on my iPhone GPS speedometer. Max RPM at WOT is 4400. Lake was flat. Engine to drive shaft alignment is correct within 0.003. Driveshaft passes the .003 trueness test on both sides of the strut. Propeller has about 300 hours on it. No knicks. If you take it off the boat and lay it flat, it does not rock when you press on any blade face up or face down. Throttle cable has full travel from idle to butterfly. I took off flame arrestor and visually looked at the position of the butterfly when I moved the driver's throttle arm. Thank you for reading and your input, Dave

Gary S Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096	Post Options Post Reply Quote Gary S Report Post Thanks(0) Quote Reply Posted: August-02-2015 at 10:03pm
	Just throwing this out there- have you ever checked the timing? I have never messed with mine but if you were to throw a light on it and watch it while you run it you could see what it's doing. And no on a governor
	69 Mustang HM SS 95 Nautique Super Sport

TRBenj Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21122	Post Options Post Reply Quote TRBenj Report Post Thanks(0) Quote Reply Posted: August-02-2015 at 11:34pm
	Id be curious which heads were put on by your quality engine builder.

utahdave Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: April-06-2013 Location: Washington, UT Status: Offline Points: 51	Post Options Post Reply Quote utahdave Report Post Thanks(0) Quote Reply Posted: August-03-2015 at 12:05am
	Engine Timing: A mechanic and I set the engine timing according to the instructions (instructions on the ECM, if I recall correctly...removing the SPOUT connector, 2000 rpm, etc). Heads: I will check on which heads are on there.

Hollywood Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13512	Post Options Post Reply Quote Hollywood Report Post Thanks(0) Quote Reply Posted: August-03-2015 at 1:42am
	Did you own it before the rebuild (and why)?

utahdave Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: April-06-2013 Location: Washington, UT Status: Offline Points: 51	Post Options Post Reply Quote utahdave Report Post Thanks(0) Quote Reply Posted: August-03-2015 at 9:36pm
	Heads are the GT 40 heads. I confirmed with the engine builder, AND went to the boat today and looked for the 3 bars that (according to the internet) are supposed to be on the GT 40 head. Those bars are there on the front and rear of both the Port and Starboard head. Pic below I have owned the boat since Summer 2011. I bought it from High Sierra Waterski school. I believe they were the only other owner. When I got the boat, the engine had about 3350 hours on it. I used it until the end of 2012. At that point, the engine had about 3500 hours on it, and the engine was taking longer and longer to pull me out of the water during deep water slalom starts than it did in 2011. I am 6'3, 200 #. At that point, the engine had significantly less "get up and go" at that point than a friend's '97 GT 40 EFI SN that has around 500 hrs on it. Roller cam installed during engine rebuild. In case this factors in: Sadly, I broke the input shaft on the transmission when we pulled the engine for the rebuild. The transmission that is in there now was new, and had been sitting on a dealer shelf for a few years when N3 boatworks bought that dealer out. I got it for a very reasonable price because they were unsure of its status and unable to sell it as brand new. Someone mentioned to me today that some Ford ECMs respond differently if you gun it. When I did my speed test, I slowly accelerate to 17, then slowly to 22, and so on. I did not gun it. Thanks for your help, Dave

Gary S Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096	Post Options Post Reply Quote Gary S Report Post Thanks(0) Quote Reply Posted: August-03-2015 at 10:02pm
	But your ECM is programed by Pleasure Carft not Ford,so they would all be the same. I wonder now if either the cam is milder than the original or if the ECM is not compatible with the camshaft if it has been upgraded
	69 Mustang HM SS 95 Nautique Super Sport

tryathlete Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797	Post Options Post Reply Quote tryathlete Report Post Thanks(0) Quote Reply Posted: August-05-2015 at 3:37pm
	Seems like a few questions are in need of answers first. 1) what was top speed before overhaul? 2) did you verify with gps (iPhone apps work for me)? 3) have you done anything recently to the boat before noticing a drop in speed? 4) assume both speedos read the same?
	2008 MasterCraft 197TT 1996 Nautique Super Sport 1988 Waterlogged Supra Mariah

'99 SN WOT: RPM & Speed below normal

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