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Flange screw thread pattern?

Chris_MI

New member
Hi,
I'm in the process of resurrecting my Baretta bowrider with AQ131D motor and 275 outdrive that has been sitting around for several years. After cleaning the fuel system and replacing the fuel pump I got it running real nice. I did find a water leak due to the copper pipe connecting the heat exchanger to the exhaust manifold not being lined up properly. The reason for the misalignment turned out to be that a previous owner had broken off one of the flange screws on the thermostat housing. So I was able to drill out the screw broken off in the head and I don't think I damaged the threads too badly in the head. I ordered new flange screws, and I'd like to run a tap down the threads in the head. The trouble is that I cannot find out which tap to use. The diameter of the screw is close to 1/4". Can anyone help me determine what tap to use? It is not anything that the local hardware store is familiar with. The part number of the screw is 947760.
Thanks,
Chris
 
Thanks guys. I was able to get this solved today. It is just a common 6mm thread. The thread gauge at the first hardware store must have had boogered up threads on the 6mm nut. I went to another hardware store and just picked up a 6mm nut out of the bin and it screwed right on nicely. So I bought a 6mm tap and got started tapping new threads. I have more time tomorrow so I'll hopefully finish the job then.
 
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