Uneven fuel consumption Port vs Starboard

[Grec]

I'm experiencing similar issues on my 2005 rinker 360 twin 496 with bravo 3s. I am in the process of connecting my engines with cables to a jbox and a gateway to my simrad go9se. I will let you know how it works out. Please keep this post updated Thanks

Just to update my posts from last summer about unequal fuel consumption between the port and starboard engine...

The good news: It turned out to be a fouled filter in the fuel line by the pressure regulator. Now that it's been cleaned, no more black smoke. No more fuel showing up in exhaust water. Fuel consumption is now very close to equal between both engines.

The bad news: The entire exhaust manifold had to be removed to access it, then replaced when it was done. Nine hours labor for a fouled filter screen.

 

[tripfighter]

that's a big delta. I assume they're running the same props and everything is in good order, not dinged, etc.?

I'm not positive it applies to the gassers but a common test performed in diesel inboards is to run one of them up to WOT to determine the stall RPM (while the other is in neutral). That exposes if one engine is making significantly more power than the other and possibly overcoming one side being underpowered. On gas engines, especially fuel-injected ones, it would make sense that the ecu is feeding more fuel to the engine doing more work resulting in higher burn.

Do you have to advance the throttle significantly further on either side to keep them synced?

Alright, so when you're dealing with diesel or gasoline engines, making sure they're in sync is crucial for smooth sailing (literally or metaphorically). In diesel inboards, one common test is running one engine at max throttle while the other stays in neutral. This helps check if one engine is stronger and making the other one look weak.

For gasoline engines with ECUs and fuel injection, the ECU takes the wheel (not literally, of course). It keeps an eye on RPM, throttle position, and load. If there's any difference between the engines, it adjusts the fuel and ignition to keep them singing in harmony.

Now, you don't have to stress about tweaking the throttle like crazy to keep them on the same page. The ECU does the heavy lifting to make sure they're working together like a well-oiled team. Enjoy the ride with your synced-up engines.

 

[RollerCoastr]

For gasoline engines with ECUs and fuel injection, the ECU takes the wheel (not literally, of course). It keeps an eye on RPM, throttle position, and load. If there's any difference between the engines, it adjusts the fuel and ignition to keep them singing in harmony.

It sounds like you’re conflating an Engine Control Unit with a synchronizer. They’re not synonymous.

I’m not wild about the diesel test either. Overloading your engines one at a time to see what happens is still dependent on accurate tachometers and may yield very little additional info over simply bringing both engines to WOT and comparing the readings.

 

[ttmott]

It sounds like you’re conflating an Engine Control Unit with a synchronizer. They’re not synonymous.

I’m not wild about the diesel test either. Overloading your engines one at a time to see what happens is still dependent on accurate tachometers and may yield very little additional info over simply bringing both engines to WOT and comparing the readings.

I think it is a valid test for diesel engines. If the stall RPM is significantly different between the two there are power issues that need to be addressed. A captain might have thought the throttles needed adjustment so their position was the same on the helm but actually entirely a different issue. This is assuming the propellers are matched.

 

[RollerCoastr]

Valid yes, but a good practice? I’m not a fan of overloading engines or recommending that as a regular practice.

One would have to assume the props are matched in pitch and condition AND that the tachs are spot-on. Those are big assumptions in many boats, particularly if they’re old enough to have no electronic monitoring.