I wouldn't recommend painting it.1 will make a mess.2 when it starts to flake will cause cavitation.and they are two dif metals and will speed up the process if paint flakes and water gets trapped and can't dry out quick enuff
And are you the guy who put tape on oil tube and lost it.and machine not going past 6000 rpms.not to sound like an asshole but I'm thinking you should have someone who knows what they are doing before you break more things or get someone hurt