When getting up on plane the port engine will stop at 3,000 RPMs even at full throttle. Starboard RPMs advance normally. Once on plane the Port engine will go above 3,000 and catch up to starboard. Just started doing this. Engines are regularly services at beginning of season - full time ups. Thanks in advance for your help!
Port Engine RPM Lag
- Thread starter Bobbyh
- Start date
-
- Tags
- engine rpm’s
Motoguy2158
Active Member
- Oct 13, 2018
- 123
- Boat Info
- 340 Sundancer 2002
- Engines
- 6.2 Mercruiser with ZF V Drives, Garmin Nav, Radar and Autopilot
Is it real? Meaning is tach giving you a bad reading or are you seeing it in performance? If its real, it could be a lot of things! Is it running rough, missing, is it bogging down and not have power? Have you heat anything and bent a prop?
Any vibration from port engine? Have you looked at throttle linkage on motor to see if its moving carb / throttle body all the way. Could be bad fuel, fuel filter or other depending on symptoms.
Any vibration from port engine? Have you looked at throttle linkage on motor to see if its moving carb / throttle body all the way. Could be bad fuel, fuel filter or other depending on symptoms.
Good question. No vibration. Yes it is impacting performance. Struggles to get on plane especially with a load. But once on plane can achieve WOT. Yes have a engine misfire warning. Had the misfire warning for a couple weeks with no impact on performance. Talked to the place that does my service when I first got the misfire warning (not Long after boat was launched on spring and after full tune ups on both engines). They said the code may resolve itself. When it didn’t and started to have performance issues they came to look
At engine and cleared the code said everything was fine but of course it came back next day. Waiting on them to come back this week.
At engine and cleared the code said everything was fine but of course it came back next day. Waiting on them to come back this week.
Karl
New Member
- Mar 30, 2019
- 6
- Boat Info
- 2009 Sea Ray 330 Sundancer, Garmin 741xs, West Marine 8 ft dingy w/5hp Lehr
- Engines
- Twin 496 Magnum Bravo III with Axius
Had a similar issue with my 2009 496 starboard engine this year and I noticed rich fuel smell. Tech found my fuel cooler modules were shedding paint. Replaced both and resolved the smell and RPM lag. Mercury has a service bulletin on the issue. Good luck.
Karl
New Member
- Mar 30, 2019
- 6
- Boat Info
- 2009 Sea Ray 330 Sundancer, Garmin 741xs, West Marine 8 ft dingy w/5hp Lehr
- Engines
- Twin 496 Magnum Bravo III with Axius
My engine sensor error cleared quickly after startup and I’m not sure they checked codes as the other info was enough to diagnose. Tech said the issue causes fuel pressure to flood the engine (90 psi vs target of 20) and that can trigger sensor code.
So here's the update - fuel cooler needed to be cleaned out and fuel filter changed - seems like I had the issue with the paint peeling in the cooler and clogging things up. That work was done but there were also two fouled spark plugs. Unfortunately the marina that does my service is about 30 miles from where I keep my boat now so they did not have plugs on the truck when they serviced the fuel cooler. I had the plugs on the port replaced yesterday so hoping that resolves my issue. I'll know tomorrow!
Motoguy2158
Active Member
- Oct 13, 2018
- 123
- Boat Info
- 340 Sundancer 2002
- Engines
- 6.2 Mercruiser with ZF V Drives, Garmin Nav, Radar and Autopilot
Ive heard lots of stories about the pain issues with the cool fuel. Seems like Mercruiser should be liable for this stuff but unless it happens within the warranty period your stuck. Sound like you will be going soon. Those plugs are available at any auto parts store. You can upgrade them to the Irdium which last damm near forever.
