Chainsaw Repair

I got a Ryobi (C4620) RY10520 , S/N ATN3020498. That is having auto oiler issues. I have cleaned the discharge port, lightly pressurized the oil tank, checked the discharge port and put a mighty vaced the discharge port. I am assuming that the pump is bad. Getting to the pump seems to be impossible. I removed all the external screws with the exception of the 4 engine mounts screws. It looks by the diagrams that the oil pump mounts underneath and is situated length ways front to rear. Between the block and flywheel. I thought i could remove half of the outer shell and gain access.
I wounder if i can find more information by looking up the homelite version? Not sure what homelite model number would be the mirror of the Ryobi?
Its a Ryobi (C4620) model number RY10520, serial number ATN3020498.
any help would be greatly appreciated.

Hi cut4fun,
I have the same pages saved to my phone with the exception of the homelite one. Thank you for your assistance. I plan to work on it Sunday. The ryobi seems to cut smoother then the polan wild thing i own. It looks like from the diagram i will have to remove the engine from the shell to get to the oil pump. To bad it dosent have the pump behind the chain gear. That would make it so much less of a project.
The next time i buy a saw i am going to check the diagrams to check the ease of service issues like this issue.
Thanks again for your help.

Thank you deezlfan. I will see what i can find with the cha of the first two letters.

Got my new bar oil pump today. Plan on installing tomorrow to cut on sunday 70°. I thought i read on here somewhere to wash out the tank. Dose anyone have the link that tells was if any soap to use? I thought about running light weight oil thru the tank and pump first?

A good rinse couldn't hurt. Splash of gas, a good shake and pour it out.

I pour the remains in with the gas going though the riding mower. The old Briggs can use as much lubrication as it can get.