I have a 2000' 90 hp Johnson outboard. When I last had it serviced, the mechanic said I needed to throw away the system and manualy mix my oil and gas. I've been through this before on a earlier 60 hp Mercury. I don't know if I should follow his advice or not. I've never had any problem and like the convenience of not having to measure and mix. What are your recommendations? If I have to throw another system away, this will be the last time I will ever throw away money on a auto-mix system unless they give me a written warranty stating the system will always work as designed and as advertised when I spend my hard earned money on it.