Selva (possible Yamaha) 4HP model 95 mixing water with gear oil (lower unit)

Hi,
This is my first posting as just ventured into marine life!
With the boat I bought, I have an auxiliary Selva 4hp 2 stroke engine. On the net I found that most are Yamaha clones. I cannot recognize the actual model. I guess it is a 90's model. The cover has a 95 sticker in front and 4hp at sides.

The problem is that water is leaking in and mixing with gear oil in the lower unit. I am suspecting water is coming in from the propeller shaft. I tried to remove the propeller by first removing the propeller nut and tried (in vain) to pull out the propeller. I tried to heat up the shaft and hammered on the nut with the lower unit suspended from the propellor.... So I am not sure if this is the proper way to take it out.

Any help much appreciated, including in actual model number etc.

Hammering is hard on things, and heat is undesirable as it can affect the seals (although in this case you are going to replace them anyway). Better to hire/buy a prop puller, or make up a puller using a large fine thread bolt to push on the end of the shaft whilst pulling against the back of the prop (like a customised gear puller etc). If you have a local outboard shop I would probably pay them a few $'s to pull it off unless you want to spend a couple of hours making up a puller. If you grease the prop shaft regularly (annually) in the future you should never have the problem again.
Check if that prop has a rubber 'bush. between the actual prop and the splined part of the hub. Larger props always do, but unsure if that one has. If it does have a rubber bush you will need to check carefully to see if it is damaged from the heat or banging/pulling. If in doubt, get a propeller repair guy to check it and rehub it if required.

Thanks Aliboy for your reply. If there is someone familiar with this model, I would like to know if the propeller is attached to shaft using splines or if this is a spring drive propellor.