I have a 55hp Yamaha, it seems to run fine but does not produce much power and goes through lots of fuel.
hwsiii has given me lots of help in selecting a good prop and we have now determined that the problem is an engine problem.
Here is the detailed thread about that:
http://forums.iboats.com/showthread.php?t=336006
I have had the carbs apart and cleaned.
I have checked both spark plugs for spark.
I have had the fuel pump apart and looked for pin holes and cracks.
I have sea foamed the engine.
I have checked the timing.
Checked cylinder compression.
With the new 13 pitch prop I get only 3630 RPM at WOT and can't plane. I think the old owner knew about the low power problem and put a 9 pitch prop on there to allow it to plane and get it sold.
After a few hours of running the plugs have a thick black oil film on them. I also noticed that there is about a tablespoon of mix oil in the bottom of the airbox that is infront of the carbs whenever I take it off (I mix oil into the gas so I am not sure how this comes out of the mix).
Could spark intensity be the issue? Or would that give me a ruff idle which I don't have?
hwsiii has given me lots of help in selecting a good prop and we have now determined that the problem is an engine problem.
Here is the detailed thread about that:
http://forums.iboats.com/showthread.php?t=336006
I have had the carbs apart and cleaned.
I have checked both spark plugs for spark.
I have had the fuel pump apart and looked for pin holes and cracks.
I have sea foamed the engine.
I have checked the timing.
Checked cylinder compression.
With the new 13 pitch prop I get only 3630 RPM at WOT and can't plane. I think the old owner knew about the low power problem and put a 9 pitch prop on there to allow it to plane and get it sold.
After a few hours of running the plugs have a thick black oil film on them. I also noticed that there is about a tablespoon of mix oil in the bottom of the airbox that is infront of the carbs whenever I take it off (I mix oil into the gas so I am not sure how this comes out of the mix).
Could spark intensity be the issue? Or would that give me a ruff idle which I don't have?