Arc problems

[nda22]

I'm using mastercamX to create G-code for my lathe, up until now I have been using TurboCNC on the machine but I wanted to try Mach3 so I installed and all seems to work fine with the wizards. So i brought up an nc program I used with TurboCNC and I get these huge arcs. I tried flipping the IJ switch in Mach's config menu but that did not make it work. Here's part of the code that will not work.

X.625
G98 G1 Z0. F15.
Z.5825
X.71 Z.625
Z2.8569
G18 G3 X1.0873 Z6.737 R40.
G2 X1.125 Z7.125 R4.
X1.0873 Z7.513 R4.
G3 X.71 Z11.3931 R40.
G1 Z13.625
X.625 Z13.6675
Z14.25

I switched mastercamX to IJ mode and got this code, but it too didn't work with Mach

X.625
G98 G1 Z0. F15.
Z.5825
X.71 Z.625
Z2.8569
G18 G3 X1.0872 Z6.737 I40.
G2 X1.1249 Z7.125 I-3.9811 K.388
X1.0872 Z7.513 I-4.
G3 X.71 Z11.3931 I39.8114 K3.8801
G1 Z13.625
X.625 Z13.6675
Z14.25

Any body have any ideas what I'm doing wrong?

[Mitsui Seiki]

What is the piece suppose to look like when it's finished?
Do you have a pic?

[nda22]

Here's a picture. Last night I worked on it some more and I discovered that if I put mastercam's "Arc center type" to "Delta center to start" I get the following code.
X.625
G98 G1 Z0. F15.
Z.5917
X.7008 Z.6296
G18 G2 X.71 Z.6406 I.011 K-.011
G1 Z2.8725
G3 X1.0872 Z6.7511 I-39.9844
G2 X1.1251 Z7.1406 I3.9967 K-.3895
X1.0872 Z7.5302 I4.0156
G3 X.71 Z11.4088 I-39.7958 K-3.8786
G1 Z13.6406
G2 X.7008 Z13.6517 I.0156
G1 X.625 Z13.6896
Z14.25
which Mach seems to like. This is a fairly simple part, I plan to try some more complex parts this weekend to see if I have really found the problem.