NS40C Cam Rod Removal for o-ring replacement on bushing

My NS40C (2 stroke 1996) gear case won't hold pressure due to bad seal on the cam rod bushing (shift shaft). I paid a mechanic $700 last year to do all the seals and the water pump (both kits) as I knew the seal on the shift shaft was blown. Long story short, they didn't do a very good job, had oil coming out of gear case after one use and water in the lower unit! I took the lower unit off myself this time and discovered that they didn't install the impeller properly, the water tube grommet was squished and misaligned and lord knows what else. The prop shaft, drive shaft seals and water pump gaskets all look good so they did actually do some of the work. Additionally, there are 5 orings and gaskets left over from the kit...

So I am going to attempt replacing the cam rod bushing o-rings myself but it is not easy to remove (way down the lower unit). Anyone done this before without destroying the cam rod? I have the service manual but it does not provide insight onto doing this. Some models/brands have a 'keeper' and the bushing is near the top of the lower unit for easier access but not this one! I tried some vice grips and a hammer but am afraid of wrecking something. ...not sure how to deal with this. Thanks!

Might be some corrosion in there. A good tug should do it.

Thanks Paul. I guess I am worried about the spring pin (part #32 on the diagram) that must be located below the bushing on the NS40C I assume based on other diagrams and photos of replacement parts. Yanking any harder seems like something is wrong or I will break something. There are a lot of crude methods on the internet to remove cam rod bushings but nothing specific on the NS40C. Below is a pic of mine. You can see gear oil coming through the inner seal as I move it from neutral to forward...

Should have been more clear. The Spring pin #32 I am concerned about or am unsure about is the one through the shaft (shown above the busing on the diagram you attached) not the one that holds the cam in place at the bottom. I have not removed any of the lower gears, drive shaft or prop shaft. Was hoping to avoid removing any of the gears or shafts as they were changed and that is beyond my comfort zone for sure! Thanks again Paul, I have read a lot of your posts and you are very knowledgeable.

At worst, you would then replace that pin. It's hardened, so it would take a lot to shear it off.