Ominous Z06
New member
Other than fuel system, is there anything else which would cause RPM limitations / limp mode on both engines?
Engines: Twin Mercruiser 4.3L EFI TBI (Gen+) w/ 377 hours ea.
S/Ns: L686113 & L686115
Symptoms:
• RPMs when running on both engines is limited to 2,500 under load and at WOT, will not get on plane & max speed of 9-10mph.
• Each engine is limited to 2,000 RPM under load when running in isolation (other engine turned off).
Already Checked / Performed:
• Ran Diacom. No stored codes in either engine.
• Both engines rev to 4000+ in neutral
• Replaced distributor caps & rotors on both engines
• Replaced both fuel pick-up lines in tank
• Replaced both anti-siphon valves (port one was full of crud)
• Clean flame arrestors
• No lose wires or sensor wires
• Fresh fuel fill & negative on water in fuel test
• Ordered Schrader fitting adapters (P/N 91-806901 ) so I can hook up a fuel pressure gauge and monitor under load
Other than fuel supply, is there anything that would affect both engines? While I await the fittings to check fuel pressure, any other likely culprits or parts you recommend I check?
Thanks,
Eric B.
2000 Regal 2660 Commodore
Port of Cincinnati OH
Engines: Twin Mercruiser 4.3L EFI TBI (Gen+) w/ 377 hours ea.
S/Ns: L686113 & L686115
Symptoms:
• RPMs when running on both engines is limited to 2,500 under load and at WOT, will not get on plane & max speed of 9-10mph.
• Each engine is limited to 2,000 RPM under load when running in isolation (other engine turned off).
Already Checked / Performed:
• Ran Diacom. No stored codes in either engine.
• Both engines rev to 4000+ in neutral
• Replaced distributor caps & rotors on both engines
• Replaced both fuel pick-up lines in tank
• Replaced both anti-siphon valves (port one was full of crud)
• Clean flame arrestors
• No lose wires or sensor wires
• Fresh fuel fill & negative on water in fuel test
• Ordered Schrader fitting adapters (P/N 91-806901 ) so I can hook up a fuel pressure gauge and monitor under load
Other than fuel supply, is there anything that would affect both engines? While I await the fittings to check fuel pressure, any other likely culprits or parts you recommend I check?
Thanks,
Eric B.
2000 Regal 2660 Commodore
Port of Cincinnati OH