Yamaha 85

I have just bought a boat with

I have just bought a boat with a yamaha 85 (grey)1998 model. I noticed that it consumes a lot of petrol compared to the mariner 90 hp I previously owned for the distance I do. My brother in law who owned the boat before I bought it told me that he used to do around 25 miles with 23 litre.the engine has got only 509 hours work. I am doing 7 miles with 25 litre. Has any body had this problem before. Up to now I changed the plugs the diaphram of the petrol pump and cleaned the carburators. What else should I check? can you please help me out?

those are thirsty

might do

those are thirsty

might do a de-carb

do you do adecarbonising only

do you do adecarbonising only after 500 hours?

I found the lower stopper on the advance arm loose the sealing paint was broken. I put it back in place and re sealed it. Now i will try it out again

i do mine every 100hrs or 1 ye

i do mine every 100hrs or 1 year