Thank you for your reply. Model is BRA23C061920, S/N is A1103880. Both O2 sensors are new, but I'll swap and check. Purchased from individual, and boat is no longer under warranty. Bryan went OOB, but I am contacting VP dealer in Houston. Is it possible there's an electrical issue that causes this? I only ask because the first time I took it out, the starter fried and the throttle system had a short. Both have been replaced.
The emissions warranty is thru Volvo and runs 5 years or 350 hours. So the issue you're having may still be covered. Only Volvo 1 800-522-1959 or a dealer can advise you.
Yes, you do need to talk to a dealer. When I run your serial number - this comes up.
Your product is subject to a recall campaign. Please contact your Volvo Penta service dealer to schedule an appointment. State your serial number as a reference.
and
Your product does not have a registered owner. Please contact your Volvo Penta dealer to complete the registration to secure efficient warranty and customer support.
Both of these should be addressed.
Now on to your problem.
Your serial number shows this engine to be a V8-300-CE-N so you do have catalysts.
The short list of possibilities. There are many more.
1 Exhaust leaks upstream or near the HEGO sensor.
2 Reduced fuel supply pressure to the fuel injection
system.
3 a non-responsive HEGO sensor, and/or
4 an injector that is stuck closed.
5 System Grounding - ECM and engine must be
grounded to the battery with very little resistance
allowing for proper current flow. Faulty grounds can
cause current supply issues resulting in many
undesired problems.
6 Vacuum Leaks - Large vacuum leaks and crankcase
leaks can cause a lean exhaust condition at light
load.
I offered up the O2 swap because it's easy to do. There are many things that can cause/contribute to this problem. Do you have a scan tool and the required knowledge to use it? More then likely This will be needed.
