bo dawg 518 #1 Posted March 27, 2010 Working on my father n law 1988 520 getting ready to go for him. Put new plugs and changed oil and filters. My question is while its running it has a pulsating idle and still does it at higher rpm. How can that be adjusted ? or is it some what normal? With throttle down the vac gauge shows it bouncing around 15 to 5. Of course when it drops to 5 the engine revs up. It's not real bad and seems to run ok other than that, but I don't know much about these engines, just too much for me. Thought it should run more steady. When reved up and driving around the house I don't notice it as much. Share this post Link to post Share on other sites
gwgdog66 23 #2 Posted March 27, 2010 Carb may need to be cleaned real good. Share this post Link to post Share on other sites
rickv1957 75 #3 Posted March 27, 2010 Yes that hunting is a good indication of a fuel system needing a good cleaning,Rick Share this post Link to post Share on other sites
bo dawg 518 #4 Posted March 28, 2010 I was afraid of that :omg: Share this post Link to post Share on other sites
Herbl 10 #5 Posted March 28, 2010 I have a 520-H also with the same problem and I also cleaned the carb or so I thought. After my first cleaning it was doing the exact same thing, surging and the choke would smooth it out. I'm into Classic Cars and one of my car friends is a Toro Tech and he told me what to do. Take the top of the carb off and use carb cleaner and squirt it down every hole you see, if you look down the ventura you can see 3 tiny holes above where the idle screw comes out, they are air bleed valves and they are tiny and they get clogged. Just keep squirting carb cleaner till you see it coming out of these 3 holes and your surging will be gone, I hope this helps it sure did me... Share this post Link to post Share on other sites
bo dawg 518 #6 Posted March 29, 2010 I was going to try some carb cleaner before anything else and see what happens. Then I may just take the top off as you say Herbl. Thanks, :omg: Share this post Link to post Share on other sites