Neutered male trying to mount?

My cat was neutered last Thursday at a free clinic by the previous owner before he gave me him. He's 10 months old. He has been walking around and yowling...mostly at night before we go to bed. Last night I noticed a behavior I had not seen. He stalks my female, jumps on her, grabs the back of her neck but by then she gets loose and runs. He chased her and this went on until we went to bed.

Can neutered males be left "proud cut" like horses, meaning not all of the testes was taken out? Should I take him to a vet? He still has what looks like plums in the back but when he came home that Thursday they were bloody from being fixed.

Any ideas?

It can take a while before the hormone levels go down after neutering. There also can be sperm in the vas deferens which can still mature after neutering so a newly neutered male actually may still be able to impregnate a female.

It takes up to 2 months for the hormones to settle, it's normal for there to be 'plums' in the back as they cut the sac open and remove the testicle so you are left with empty sacs.

Thanks! Makes me feel better. I should know this after having my 17 year old stallion gelded. He is still trying to mount my daughters horse and he was castrated in Dec!