WildmanC120 613 #26 Posted February 9, 2020 2 hours ago, lynnmor said: The vacuum port in the intake next to the carb appears to be OK and closed, just make sure it is not drilled thru. There is a welch plug next to the idle mixture screw, make sure it is there and sealed. Make sure that you didn't use E15 or E85 fuel. The spray you are using evaporates so fast that the test may not be valid, try again with some oily spray or just plain oil. Are you using the correct Champion spark plugs? That black/white contrast is extreme. A valve that has near zero clearance will show an excellent compression test, but the clearance will quickly go away with just a little warm up. It sure does seem like it is sucking air. I pulled the plugs and did the compression check after the video, so the engine was nice and warm. The spray was just carb cleaner. I used most of a can between the video and off video and couldn't get it to change. Unsure on the plugs. Those are the plugs that were in it. The only thing I can think of that could be leaking vacuum is the port for the original fuel pump. That seems extreme and I wouldn't think that little bit of choke I applied in the video would have fixed that. The fuel is 91 non ethanol. Share this post Link to post Share on other sites
lynnmor 6,777 #27 Posted February 9, 2020 Idle the engine as slow as it will run and adjust the idle mixture screw, hold the throttle stop screw against its stop while adjusting. If it speeds up, repeat as many times as necessary. I’m trying to determine if the idle circuit is supplying enough fuel. Share this post Link to post Share on other sites
Tuneup 1,416 #28 Posted February 13, 2020 Well WM, I'm going to be in the same spot around this weekend. Mine had a missing welch plug and you can imagine the amount of choke needed to stabilize her - didn't see it until I pulled the carb and intake. I made one out of an old watch battery and it's ready for assembly and firing. If all leaks have been considered and sealed, it's time to adjust at the governor. You can play, as long as you remember its original setting. I'm just hoping I fire it up and she's stable. I've got enough to do around here... Share this post Link to post Share on other sites
