Just purchased an 05 Express HD18CC w/ Yamaha 90 about 3 weeks ago. Third time taking it out today and noticed when I put it in reverse, made a strange sound so after putting it in forward, it would shut off. I plan on taking it to a mechanic when I have time, but any ideas with my mechanic friends on here? I noticed when I would put it in reverse, it would act like it is in neutral then would be tough to put in neutral but once engaged to go forward it would die. Possible Shifting linkage? and if so what is a ballpark price on a 90 Yamaha? Thanks for the help in advance!

by your description, it almost sounds like the lower unit clutch dog pin retainer came unwound and locked it up. have you drained the lower unit gear oil to see if any chunks of metal come out? anywho, do not crank it up and try to put it in gear anymore till it gets checked out