The post about the marine shop in Havasu got me thinking. We have owned a auto repair shop in so cal for 65 years so I have a little insight on trying to give good service. When I read the post two things caught my attention. The owner taken steps to remedy the problem and had already ordered parts before the problem was properly diagnosed. In my experience those two things are a red flag. A shop should always diagnose a problem before any parts are installed. Some times (not sure in this case) the owners do not want to pay for a diagnosis first and when the parts supplied by the customer does no fix the problem they almost always want a discount or credit of some kind. This is reasons #1 why i will not install customer supplied parts. Reason #2 is the profit of the parts is how i pay my bills Most shop run a 50 % parts labor split that means that half of there sales are parts (The parts labor split my be different in the marine industry ) A well run shop should make a gross profit of about 60% on parts and labor. Know some may thing that is a big profit margin but after all the over head is payed the owner will net about 20 to 25 % of the total sales. I am not asking for any one agree with me or change any ones ideas about trying to supply there own parts. But thing about this would you ever go to Roadrunner of Foxs and bring a cooler with beer in it even if you were buying food there or think in would be ok to order a coke then add your own alcohol trying to save a few bucks? The thing about not returning Phone calls. 100% wrong some times people forget we are in the service business Good service brings people back. There is a saying if you expect good service start off by being a good customer