300 idle question

Just had the carb on the 300 boiled and rebuilt. Runs great and has gobs of power Only problem is, it idles fast. Have the idle jet turned almost all the way in. Checked throttle connection 3 separate times and made sure the governor was adjusted per I&T manual. Put it under a load and it idles so slow you can nearly count the cylinders firing. But when it sets, it idles like it's at 1/4 throttle. What have I done wrong?

Mac

The throttle plate is not centered in the bore. the stop screw must be loose, then the plate screws are loosened, then turned to contact 360, then tightened. Jim

Thank you. Ill give it a whirl tomorrow and see what happens.

Mac

where are you getting the gobs of power from when its only idling under load? probably have to do a brake job on it as once tuned up as you will have a run away.

Idle jet is mixture idle speed is controlled by the idle screw on the linkage

What I mean is, I have 2/3rds of my throttle range. The bottom 1/3 (idle) is just not there. At 3/4 throttle it will pull my 8' disk with and 8' spring harrow behind it all day long, and it has no problem on my 7' brush cutter. It runs excellent. It just don't idle down.

Mac

Several things to check. First back out the screw close to where the throttle tube goes on carburetor. Next make sure crude hasn't built up behind governor housing and keeping the throttle lever on the governor from going full forward. Take connecting rod out of the governor throttle lever, push lever forward by hand with idle speed screw still backed most of the way out. If it idles correct or if it dies turn the idle speed screw in for a slow idle. If that works you need to adjust throttle linkage or you didn't have the idle speed screw correct. Still won't idle down? Take the top cover that has the pipe tube off governor housing. See if you can push down on the vertical link with finger to get idle. If not you need to check inside governor or carburetor or look for a air leak. Was the carburetor throttle shaft removed? Above is provided you set the governor link and tang in notch to carb correct when it was installed. If you need to look in governor make sure lever at rear of spring in picture is just moved to rear at idle and the top bolt with jam nut hasn't been run in to far. Best to check governor with hand throttle link unhooked and move lever by hand in case linkage is off. Can suggest more if none of that works.

OK men, here's what I've done so far: checked throttle plate per recommendation. It checks out good, 360 degree contact. Next, tried all the governor tricks as d Slater mentioned. Only thing that jumps out is I can push the small rod down about an inch, maybe less. How would I adjust this out? As a side note, I disked 5 acres today and had no issues. What's strange is it was fine before I had the carb off. I did have a loose coil wire causing bad running, but it was fixed. I wouldn't think that'd cause this? I'm not too heart broken about it, but if I can I'd like to fix it. It runs too well not too.

Mac

When the lever behind the governor housing is forward the part with rear spring eye or right in picture should move to rear far enough to bring the adjustable vertical link down so throttle tube shaft brings carburetor shaft to idle speed stop screw. Could be throttle linkage has lost movement or needs adjusted. Or the top adjustable stop screw inside the gov. could need backed out a little, but I doubt it if okay before. If linkage is set so carburetor plate is wide open not running to start with, then when throttle is moved to idle the spring needs to push the rear eye back enough so vertical link brings carburetor to idle. You have lost movement someplace if you can push the vertical link down to idle with finger when running. If the spring is weak it takes more lever movement from idle to full throttle. Also check when not running to see if the hand throttle moves the governor stop screws to the housing contact points when in full and idle hand throttle setting. Bushings in the spring eyes like the picture can help with lost movement but most can work without that. Now with good full throttle running if you move hand throttle to idle and then remove rod from lever on back of governor housing and push it forward by hand, will that bring it to idle?

I almost understand what he is talking about. I cleaned my carb up a couple of times and when starting it up first time in the day, it runs a little bit higher RPM than before. Almost like cleaning it up cleaned some of the varnish and now there is more fuel going into the intake. That is before it starts coughing and sputtering. I would wonder if it needs a needle valve adjustment. When I removed my carb and prepared to clean it the second time, I pushed the needles in to get a gauge of how far to pull them back out after the cleaning. 2 turns for the main outside needle and 2-2.5 for the air needle. Not perfectly sure on the air needle as it took me a while to get that part cleaned and I had a minor distraction. Also did not write it down. I left the cable outer connected to my 400 carb bracket and put it back in the same condition. I may need to adjust it back a tiny bit after all is said and done. Thanks for bringing this up. I appreciate it as well.

Ok, so I disconnected the lever while idling, no change. Governor screws are ok and havent been messed with. I'm beginning to wonder if the carb guy might have not put the little throttle/gov. connection plate back in the right spot when he rebuilt it. Will check that first chance I get. Its been a rough couple of days between rain showers and tearing up dang near everything I own. Broke the disk, sprayer and weedeater... just on a Saturday! Just in case anybody is curious, an 8'6" disk will NOT go through and 8' gate. Also, clean your sprayer pumps out before winter storage... and the weedeater? No clue, just quit. Oh well... Will let you guys know what I find out. Going to finish planting beans and a little corn hopefully tonight, then gonna tear into it.

Thanks again,

Mac

What would happen if the choke adjustment was off??? Just asking to myself out loud. he he he....

and the weedeater probably has a problem with the fuel. You could probably take the bubble off the carb carefully and the gasket/fuel intake, clean that out with the spray carb cleaner, and it may go again. Did that a couple times with my wheeled weedeater. Check your fuel filter inside the weedeater tank too. Mine was expanded and had to be replaced. Had to buy the kit and replace both hoses anyway. The accelerator line rusted thru too and I had to purchase a temporary until the replacement got in today too. Temporary is still on at the moment. My buddy had a problem with his hand carry weedeater. I told him to hold the accelerator down a bit to start it as I did not want to get in and clean the varnish off. I think he still is doing that until I get my set up prepared so I can fix it. I have several and can fix one before getting his done. That way he has one while I fix his. Run them out of fuel before you put them up for the year...that way there is no varnish left inside to gum up your engine.

Alright, we got idle! I went back through the carb and made triple sure the throttle plate was touching all sides. Double checked the top of the governor and made a minute adjustment there. Inside the governor, everything was still fine. Put the carb back on, triple checked throttle linkage. Fired it up and she'll idle about 400 or so. Now that's over, I get to replace the alternator on the 2000 Ford. And my sprayer pump. And my weedeater. Jeez it's been a long week! Thanks for all the good advice. Glad Im a part of this great forum.

Mac