Air Bubbles in Fuel Line

[bigboat606]

To check the fuel pump on my 1987 200 HP Evinrude, the manual states to use a clear hose at the input to the fuel pump, then run the engine a high speed and look for air bubbles. I recently replaced my fuel pump with a non-oil injection, pre-mix type and the engine runs great. But I do have a few small air bubbles going into the fuel pimp at higher speeds. Do these air bubbles affect the engine performance or is the air bubble concern only for oil injection models where the oil/gas ratio could be altered?

 

[clemsonfor]

Re: Air Bubbles in Fuel Line

im no expert but i would think that that would just be for VRO pumps. A old fuel pump just moves the premixed fuel to the carbs then it is pulled into the engne. So an air bubble that is small is only going to mean that the needle vale does not close for a millisecond longer. The vro pump senses fuel goinginto it to change the amount of oil mixed with the fuel. So if ai is introduced there will be to much oil in that amount of furel that is introduced at that time. Again im no expert. I have a VRO boat but luckily i have never been into the VRO on it, i have been into my premix motor and older one a lot though.