Source of poor idle

I have been trying to find the cause of spradic poor idling on my motor
1998 Johnson 175 FastStrike
J175GLECD

Doing some cleaning today I noticed cracks on the float bowls at least 2 of the carbs. The bowls are plastic and you can see two clear cracks on the two top starboard side carbs. I cannot see the others but I suspect that they are cracked as well. I can also tell that the seal between the bowl and the body are not good. First off what causes this? Is this a job that I can handle or should I take it to a dealer? Will it harm my motor to continue to use it until I get it fixed? What am I looking at cost wise. It looks a bit hairy to disassemble, makes me nervous.

Is there fuel comming out of the cracks, or is it a mold deformity?

Easy to do for a skilled Tech, take the short drive out to Lebanon to Music City Marine and see Rusty, He'll fix you right up in quick time. http://www.bassboatcentral.com/smileys/wink.gif

I could not see any fuel physically coming out but there are definitely cracks. I am still miffed as to what causes such a thing? I will take it to John to take a look.