buckweat

Thanks for all the help, I did a search and read and read. Today I started it up to see if their was any sign of residue or bubbles in the antifreeze. I also was looking to see if it would just plane poor out all over the place. Nothing no sign of anything, not even movement in the fluid. It stays cold as the head heats up to where I can't touch it. So I took the pump cover off to see whats up. Should this spin when you kick it over cause it doesn't I can free spin it, with no resistance at all. So now my question is how do you replace this and would this cause it to sputter.

Ok I just rebuilt the top end on this shee. Put it all back together and it starts fine every time. When warmed up, in neutral from idle to WOT sounds great, no problems at all. Put it in gear and 1st and second gear fine third gear all the way through 6th and it sputters bad. Just wont run right at all. What I think may be the problem is I have a tiny leak in the head gasket, cause after running through the gears till I reached top speed, I let off the gas, and saw a little white smoke or steam, not sure which, come out of the pipes. What would be the easiest way to check for a hesd gasket leak and what are the tail tail signs of this problem. Have not run it much maybe a total of 30 minutes since the rebuild would I see any signs on the plugs, cause they look ok to me, tan to brownish and fairly dry. Any help would be great.