149 stripped oil drain
 

Went to do my 1st oil change on my 149 and after draining the oil out I went to put the plug back in and all the threads in the oil pan are gone. Looks like someone has messed with it before cause the drain bolt is a stud with a nut welded to it. The threads on the plug are fine, just nothing on the pan left.
1st of all what size is the drain bolt as I don't have a correct gauge with me to tell and second, what do you think the best route to go to fix. Should I try the plug size tap and see if that works or go the next size bigger

The drain plug is 3/8 NPT.

ALL the threads are gone? :bigeyes:

Yea just about. It's pretty smooth, idk if I can get a pic of it or not

The plug that's in there is bigger than 1/2"

You may be able to tap it deeper if you use a hex drive set screw as your plug.

As a general rule, NPT taps are the correct depth when they are 2/3's of the way up the tap. ( obviously a gage is better but that will get you close ). A set screw style plug will allow you to sink it deeper.

I use these in my Cubs
http://img.photobucket.com/albums/v7...h_DCP_5226.jpg
click for bigger pic

NPT threads are bigger than the actual fractional size. The 3/8" NPT is sized for a piece of pipe with a 3/8 inside diameter.

I've had cast iron pans that had 3/8 pipe threads and aluminum pan with non pipe plug threads.

If it was my Cub Cadet I would change pan.

I would be concern about having metal shavings in side the pan.

Would a taper or straight tap be better. I wanna try retapping it first, replacing the oil pan would be a last option.
I have a small magnet I moved around the bottom of the pan and didn't get anything out. Most of the threads fell out with the bolt

thats because the pan is aluminum.

Merk said some aluminum pans had straight thread. I'm a NF guy and all mine have cast iron pans which are 3/8" NPT.

Do you have some way of measuring the hole? Maybe yours was originally a straight thread. :bigthink:

If you decide to tap the pan while it's still bolted to the engine, FILL the tap flutes with grease to catch the chips. Replace the grease often to reduce the chance of chips staying in the pan.