26,
What did your mechanic say about the latest problem? What jets were you running when she blew? Did she blow at mid range cruise or WOT (wide open throttle). Are you running power valves in the carbs? Did you check fuel pressure at WOT? What fuel are (were) you running when it went south?

JB

I would agree with the theory that you may be running rich at idle but going lean on the big end. Electric fuel pumps are nototious for not working well in a boat since they do not draw fuel efficiently. They must be mounted lower that the fuel tank to work properly which in most boats is nearly impossible. Remember the Merc uses the same mechanical fuel pump on the HP motors up to the SC600.

The only way to know if you are getting enough fuel at speed is with a pressure gauge mounted at the carb inlet.

I dont have a fuel pressure guage on it at this time but it probably wouldnt be a bad idea to put one on. I do have the fuel pump mounted lowwer than the fuel tank. I dropped the motor off yesterday for him to figure out what he has to do to fix the problem and to see if he is going to cover it for me. As soon as I find out what he is going to do I am going to order a fuel pressure guage, a water pressure guage and a oil temp guage. I figure that is the only way I will figure out what is going on. I might end up having to put the stock fuel pump back on.