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View Full Version : Is there a high speed cutout on engine


Bruce
04-03-2007, 03:51 PM
Yesterday was beautiful so I took the wife out for a ride. (she is going through chemo and it was a nice diversion). After some nice slow crusing I decided to bump it up. I had just bought a hand held GPS and since my speedometer is so far off it was a chance to check it out. I firewalled it and it got to 47.5 mph at 5000 rpm's. As I was looking at the GPS I felt the engine drop out. Since I was looking at the GPS and it happened so fast I don't know if the rpm's exceeded 5000 for a split second or not. Is there a high speed cut out on the 5.7 Vortec? Basics: 1999 Maristar 230Vrs with 5.7 and std. tranny. Wgt load with wife and self about 275 lbs. I felt that speed was pretty good for a boat that size.( Before I get yelled at no, I won"t do it again) By the way it is 4 blade prop don't know the specs. I have only put about 20 hrs or so on it myself and don't know if it is original prop or not.(total boat hours about 340)

JKTX21
04-03-2007, 03:54 PM
This happened to me one day last year, but mine bogged down at about 4500 RPMs and then sounded like an explosion (maybe 180 degree detonation) from the engine. Started up fine and had it tuned after that.

trickskier
04-03-2007, 04:00 PM
My old ProStar had a rev limiter at 5500 RPM's. My new MCX turns 5300 RPM's

PendO
04-03-2007, 05:14 PM
you could see how it compares to any boats like your setup on this thread

http://www.tmcowners.com/teamtalk/showthread.php?t=11251

bigmac
04-03-2007, 06:25 PM
Yesterday was beautiful so I took the wife out for a ride. (she is going through chemo and it was a nice diversion). After some nice slow crusing I decided to bump it up. I had just bought a hand held GPS and since my speedometer is so far off it was a chance to check it out. I firewalled it and it got to 47.5 mph at 5000 rpm's. As I was looking at the GPS I felt the engine drop out. Since I was looking at the GPS and it happened so fast I don't know if the rpm's exceeded 5000 for a split second or not. Is there a high speed cut out on the 5.7 Vortec? Basics: 1999 Maristar 230Vrs with 5.7 and std. tranny. Wgt load with wife and self about 275 lbs. I felt that speed was pretty good for a boat that size.( Before I get yelled at no, I won"t do it again) By the way it is 4 blade prop don't know the specs. I have only put about 20 hrs or so on it myself and don't know if it is original prop or not.(total boat hours about 340)I had that exact thing start happening when my boat has about 2 hours on it. Then, it started happening at lower speeds. Then, it started happening when I'd accelerate from any speed. Then it started dying periodically. Then, the dealer replaced the fuel pump and it's worked great ever since.

My guess would be that your experience might have been a piec of fuel tank crap that blew through the engine, or a transient blockage of the fuel pump. I wouldn't worry about it unless it does it again.

Leroy
04-03-2007, 06:25 PM
I have the LTR but believe they are limited at 5000 RPM. I normally get 46.x for top end at 5000 RPM.

dpolen
04-04-2007, 03:50 PM
I have the same issue with my 1998 Maristar 225 with the same engine you've got, this started when I changed my props to one with less pitch, thus the engine was hitting the rev-limiter. I put on a 14x18 prop after I hit a rock with my 14x20. I'll be putting the 14x20 back on as soon as the boat comes out of storage to hopefull fix the problem.

Bruce
04-04-2007, 11:51 PM
Hi guys thanks for info. based on what dpolen said and Leroy implied there must in fact be a rev limiter on this engine. May not be called this but I get the idea. How about it MC dealer/mechanics is this correct? If so do you know at how many rpms this happens on this engine.

Ric
04-05-2007, 09:11 AM
Bruce, sounds like she is a fighter! Our prayers are with your family!

dpolen
04-05-2007, 09:47 PM
Bruce, I did validate this scenario for my problem with the local MC dealership...not sure if that addresses your question, but just my 2 cents I thought I'd throw in. As far as RPMs go, I'm pretty sure it was below 5000...closer to 4500-4600 if memory recalls.