Rough running when warm
 

Johnson 175

Motor starts and runs great when cold, she fires up and idles pretty damn smooth considering her vintage. Problem is after she has been running a while she hates to idle. Example, ran about an hour Saturday and when I got to the marina she stalls out and runs rough when pulling in. Again, once I went to start her up (after sitting for lunch) she won't idle and is hell to get her past 1500 rpms. Once past 1500 she is fine but getting her there is tricky. It will stall out almost as soon as I begin to throttle up, the only thing that seems to work is to keep pulsing the primer/choke/key switch until I can ease her up past 1500. I replaced the primer bulb hoping that was causing a fuel restriction, nope. Now onto the actual fuel system. Carbs or Fuel pump? Where should I start. I have a fuel pump from a 150 Johnson, same vintage, if I need to swap but would rather not unless I have too. Any suggestions?

Thanks.

-Svence