Engine cuts out at High RPM

[sates]

I have a generation V 454 wich i have added vortec heads and edelbrock rpm intake. When I rev to 4200 rpm it cuts out like there is a rev limeter or as if its not geting spark and does not want to fire. It does not quit just starts to gargle at 4200. I have new plugs wires cap and roter and coil. Could this be a timing issue? IT runs perfectly till I hit that rpm. I am stumped.

 

[sates]

I have a generation V 454 wich i have added vortec heads and edelbrock rpm intake. When I rev to 4200 rpm it cuts out like there is a rev limeter or as if its not geting spark and does not want to fire. It does not quit just starts to gargle at 4200. I have new plugs wires cap and roter and coil. Could this be a timing issue? IT runs perfectly till I hit that rpm. I am stumped.

 

[addgasgofast]

It could have a rev. limiter it just dependes on exactly which model of 454 you have. If yours was an 330hp one 4200rpms is right for the limiter to kick in. One of the stearn drive guys can tell you more specific info if you post what model 454 you have. Good luck, I think you just need a modual with a higher rev. limit to take advantage of the mod's you have done. Later,addgas.

 

[vinny p.]

While I don't think that timing is your problem....What is your total timing set to? It should be at 34*-36* @ about 3000-3500 rpm. How is the fuel system? Are the floats adjusted correctly? What is the fuel pressure at all rpm's?
It can be a rev limiter, but I don't think that Merc made one that comes in at only 4200 rpm. I am not sure on that one.

 

[sates]

I have the 330hp casting # is 10114182 1991 and up 4 bolt Gen V. Timing is set to factory specs. Im pretty sure I dont have any fuel problems.

 

[vinny p.]

You say you dont have any fuel problems but what is the fuel pressure at various rpms? You have to be able to maintain 6 lbs at w.ot. What carb are you running?

 

[happy]

which method did you use to adjust the valves??? check all your abc's.. wiring harness.. all grounds especially on the ignition side... you could have thunderbolt 4 or 5 on her.. make sure the ignition sensor, and ignition module are grounded, and all plug ins corrosion free and the pins in tact. I forgot the name of the goop that is supposed to be used on the coil wire where it plugs into the coil.. maybe vinny remembers.. this stops it from arcing.

 

[sates]

I had the wrong serial number It is F757494, Does anybody know if this has a rev limiter?

 

[vinny p.]

Happy,

You mean Die-Electric Gel. That stuff works great. I use it on both ends of the plug wires.

 

[happy]

Interesting note.. while at work yesterday.. a walk in customer was looking for a 502 in which he wanted to stroke out to a 540.. and was wondering if all his parts on the outside of the block would work.. so i got out my cheat sheat.. your engine has a knock sensor.. which may be causing your engine to cut out.. however should be around 4600 rpm

 

[vinny p.]

How would a knock sensor cause an engine to cut out at 4600?

 

[happy]

the knock module monitors the a/c voltage signal and supplies 8-10 volts to the ignition control module when no knock is present.. if knock is present it removes the voltage, which inturn de-activates mean best timing,(mbt) droping timing to a safe level..

 

[vinny p.]

OK I agree with the fact that a knock sensor will retard timing, but that doesn't make it act as a rev limiter.

 

[happy]

i guess untill we hear back from sates.. we'll never know.. .. it was just a thought that may have helped.. there simply isnt enough info yet to work from..

 

[boatn70]

i believe he has the same motor and setup i have, the rev limit is at 4600 and it does have the knock sensor. dont really know much more about the knock sensor other than it does retard the timing to stop the knock.

 

[sates]

I found that I do have the knock sensor after looking up my ignition. It seems to be kicking in at 4200 to 4400. I was hoping to reprop and spin it up to 5000. What other information do you need or are you talking about.

Been out of town on business for a while, sorry.

 

[vinny p.]

Forget about the knock sensor, that is not your problem. It will not act as a rev limiter. I don't think that your problem lies with the ignition at all. If your motor has a working factory rev limiter , it will not be set so low. I still have to ask you the same questions again... What is your fuel pressure set to? What is your total timing set to and where does it come in at?
I feel your problem is fuel related.

 

[daren34]

have you checked your water seperator
did you get gas any place new

water in fuel will cause exactly what you
are describing

 

[happy]

alot to consider on this one.. whats the spring pressure on the valve springs... ? same cam??? and was the engine in tip top shape before any mods were done??? were any compression figures obtained? what type of exhaust are you running.. which ignition system??