Inconsistent idle

[captchuck]

I know it's not a diesel question but here goes. I have a Volvo 5.7 carbureted straight inboard in my 26 seaway. Electronic distributor and a Rochester carb. Only issue I have is that the idle is rarely the same for example after I ran for around 45 min yesterday and when i came into the creek and up to the dock the idle was so low she wanted to stall and at times she will idle too high say around a 1000 and therefore she knocks in and out of gear a little.
Any thoughts? Thanks guys

 

[jerseysportfisher]

first check the easy things, is your throttle linkage binding ? when you move the throttle up and back does it always return to the same spot on the carb every time ?

 

[Pedlyr]

Could be a vacum leak. Either base of carb or intake manifold.

Check the little filter at the carb on the supply line and make sure it's clean.