POPS aka Ben Corn - Regarding Your engine swap from the 1650 to 126. The K301 (12 hp) into the 1650 makes it a 1250 with optional hyd. lift, No Problem. However, the K341 (16 hp) is a large flywheel engine, Almost all 321 & 341's are and Your 126 is a NF tractor and will require the frame mods IH did to the 147's to drop the K341 in.
I didn't want to cut & weld on the frame on My 72 to drop My K321 in it and after much head scratching finally thought of the idea that I could swap flywheels, sheetmetal, & blower housing backing plate from the K301 in My 129 I had at the time making it a "Big Flywheel K301) and making My K321 the "Small Flywheel" engine I needed for My 72. It only took Me a couple hours after that to have the K301 out of the 129, the parts swapped and the K301 back in the 129. If this is the way You decide to approach this be warned the K301 will still be a 12 HP engine but it will seem pretty lazy. The big flywheel weighs the same as the small one but all the mass is further out from the shaft centerline so it acts MUCH heavier and the engine won;t wind up as fast. But on a happy note Your K341 will seem like a Race Horse, Snappy as all get out!
Rope pull starting a K301? Yes, It's do-able...if the ACR is working fine, the tune-up is spot on, and You have the room to get a good straight pull on the crankshaft. The ACR on My K321 sticks every once in a while. When it's working fine My old Starter/generator spins the engine over and it's running about the second time the piston comes up on TDC, but when the ACR sticks it just spins the S/G pulley inside the belt. I actually think the K321 starts easier than the K241 it replaced. I know the K241 vibrated worse!
