Yahama 1999 200 H.P. Two Stroke

[AJAK]

I have a pair of Yahama 200 H.P. Engines, the Port Engine is using approximately 25% more Fuel and Oil than the Starboard Engine. Also, when I flush the Port Engine I notice an oil/gas slick around the lower unit for a few minutes. The mechanic had the fuel injectors rebuilt at the beginning of the season becvause he said when he prepared the boat for layup last May he noticed the Port Engine was not picking up on all cylinders and traced the problem to a coule of clogged injectors, he had them all rebuilt. I noticed the same problem last season so he did not cause the problem with the injector rebuilds.. The mecanic is not a pure Yahama Mechanic bu he has been good in resolving problems during the past. Last season I did have to replace the fuel pump on the Port Engine but the gas and oil usage was not right before that repair. I know in a dual installation that both engines will never be exact but this seems nuts to me and the fuel management system verifies the variation in the fuel usage. An example would be at 2,900 RPM the Port Engine might be using 9.0 GPH and the Starboard shows 7.6 GPH. Even at slow speeds there is a difference.

Sorry for the length of my post. Any help would be appreciated.

Thanks,

AJAK

 

[rodbolt]

Re: Yahama 1999 200 H.P. Two Stroke

check fuel rail pressures. a clogged regulator filter can spike pressure and increase the amount of fuel used. also make sure all linkages,TPS voltages and the oil pump link rod are set correctly
a quick session with the diagnostic test lamp will show if there are any sensor,other than O2, issues.
if the ECU sees the o2 sensor missing fuel will be fixed rich at low speed and lean above 4000.
the O2 sensor is easily tested with a DVM and the test harness.
on the oil consumption.
oil is metered by the pump and the throttle linkage only. you may have 2 issues going on.