1997 Yamaha 200hp Saltwater Series Carbureted twins fuel consumption not even close

[Groupergulper]

Twin 1997 Yamaha 200 Saltwater Series CARBURETED Both motors Rebuilt powerheads. same props. Both motors run great , both motors have a separate fuel tank. the port motor is burning a lot more fuel than the starboard. Last fill up was 43 gallons on starboard side, 55 gallons on port side. From an offshore trip so mostly high rpm 4000-4400. thats 28% WOW . Both motors were rebuilt by marinas by the previous owner so all I have is what the receipts say. Neither motor seems to run rich, plugs look good in both motors. Seems like its getting worse. The fuel tanks are not leaking. I don't see any gas leaks or smell any. I keep them full so i can check mileage for the complete trip. Both tanks show full on the gauge and we fill it till it shuts the nozzle off.

The oil consumption seems to be relative to the fuel consumption. I haven't measured the oil but always a lot more in the port side.

Starboard - .040 oversize 250 hrs
Port - Oversize but not sure how much 350 hrs

Only thing i can think of is the jets in the carb are different? when you bore a powerhead I assume the jets would need to be changed so it isn't lean ? would be the same though not get worse.

Tested today.
Port motor 1.5 GPH 700 Rpm
Starboard motor 1.2 GPH 700 Rpm

Port motor 14.5 GPH 4000 Rpm
Starboard motor 10.6 GPH 4000 Rpm

Doesn't make sense to me.

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[ondarvr]

Normally the jetting doesn't change, but some rebuilders put in larger jets for break in.

​If one motor has low compression, or just puts out less power, the throttle position may be higher than the other one to turn the same RPMs, so more fuel is burned.

 

[Groupergulper]

Maybe, the throttles are adjusted the same and in the same position. I have not checked the compression.