454/340hp dead at 2,000 RPM

[allans]

I read a posting about a similar problem with a 454 crusader. My engine is a Mercruiser,1990,in a 36'Regal Commodore, only 310 hours. New Electronic Distributor Pick up and Rotor,Wires, and new Fuel/Water separator and still pops and dies out at 2,100 RPM under load! Will immediately restart, runs good at idle, and NO load at Dock(3,000+ RPM)!Checked Voltage on batteries, cleaned Carb filter! Any ideas Guys, by the way, this just started last week??? Could a Bad Distributor cap cause this??

 

[dockknocker]

Re: 454/340hp dead at 2,000 RPM

Check you cap and rotor then if they are OK check your plugs. I spent over 1,000.00 doing the carb cap rotor wires and found a bad plug. Check those plugs.

 

[metwrench]

Re: 454/340hp dead at 2,000 RPM

Sounds Fuel to me...Under Load is Croaks, But restarts Immediatly. I would try and get it up to speed and as its Dying, shoot a Little Starting Fluid in the carb and see if it stays going.<br /><br />Please be really careful in doing this because a Lean Misfire could back fire through the Carb and start the fluid on fire..so Please Be careful.<br /><br />Does it POP through the Carb when this condition Happens ?<br /><br />If youi have a Timing Light, Attach it on the COIL wire...at the time it dies, check and see if the Light on the timing light is still flashing...This may give you an Indiacation if your lossing Fuel or Spark.<br /><br />A good Investment also to make is a spark Indiactor. Some company's make them, they go between the Plug wires and have a glass shell. When spark is send, the bUlb lights. Normal engine at Low RPM you would see this Light Flash. Its a Great Tool for short Money, for quick Diagnose. <br /><br />Hope this helps

 

[allans]

Re: 454/340hp dead at 2,000 RPM

Yes John, it does POP through the Carb, I will try the "Starting Fluid" trick this afternoon. I will try and get one of those Spark Indicators also, changed the coils out last night, with no change! This has original Fuel Pump (14 years old), could it be "Breaking Down" at 2,000 RPM?<br />Will advise any progress 8/19! Thanks-Allan

 

[allans]

Re: 454/340hp dead at 2,000 RPM

Update to my fellow Cadets and Seaman. Found some teflon tape in the draw tube screen, but boat is still dying out at 2,200 rpm! New Fuel pump, plugs, etc. completely baffled ? I guess the Carb is next, unless you guys have a "NEW" idea? Idles great, starts easy-Just starves for gas!!Could the shut off valves get clogged?<br />Thanks!!

 

[Mahoney]

Re: 454/340hp dead at 2,000 RPM

I would check the timing advance on the engine as you bring up the rpms, using a timing light as the rpms increase the timing indicator on the crank case should advance with rpm's and settle back down to the correct idle timing when brough back to idle. I am kinda learning all this but I manually messed with the timing as my engine was at rpm's and as I rotated distributor to bring the timing down to its initial idle timing, esentially canceling out the advance that was correctly taking place, then engine will die.

 

[jimmbo]

Re: 454/340hp dead at 2,000 RPM

Does your engine have electronic spark advance or conventioal design with weights in the distributor? <br /><br />Does your engine have 4 barrel carb? and if so is it a Q-jet? If it is a Q-jet make sure the secondairy lockout is not stuck preventing the secondairies from opening.

 

[llerrad]

Re: 454/340hp dead at 2,000 RPM

Had same type of engine trouble, found blocked fuel line, fuel pump to carb. and yes this is after the fuel filter with a change every season. You might remove the line and give it a shot of air, could be a cheap fix.