Excessive fuel consumption

[ChrisB54]

Bought an old boat with 1990 115hp two stroke. Runs ok, a little touchy to start hot or cold. But it uses an extreme amount of fuel. I'm familiar with old two strokes using a lot of fuel but this is extreme. Less than an hours running at various low speeds, up to about 20 knots and less. Cruising around on a choppy day and used 8 gallons or 30 litres of fuel. Carburettors look clean and jets are clear. Any suggestions would be greatly appreciated.

 

[racerone]

Inspect floats / float valves in carburetors..-----Replace fuel pump diaphragm.

 

[ChrisB54]

Float valve seats are ok and floats look level when closed although I don't know the factory setting. Diaphragm seems like something that could cause this. Thanks I'll check them.
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