Awhile back I posted about how I fixed the problem with Honda HA4's stalling above idle by removing the air cut-off solenoid and plugging the hole. Well a few weeks back when we had that frigid cold air I when out to start the Honda and after it a couple of very slow cranks it started but the stalling problem was back. After the weather broke here I found time to work on it and found the the rubber plug I had installed had been sucked forward in the hole and had blocked the pilot air again. I guess there was enough vacuum on that cold morning to do it. This time when I took it apart I removed the rubber plug and tapped the brass hose tube to 5/16"-18 and installed a set screw in the tube. In the picture below the red arrow points to where I had put the rubber plug and the green arrow shows the threads in the brass tube. I've be running it for a week now with no further problems so I think this time it's fixed for good. This is what it looks like installed on the carb.
Carburetor Air Cut off revisited to solve bogging down This is an easy fix once you know what the problem is. I read your previous posts and it helped me fix a problem that nagged me for weeks. Here is my version. The air vent cut solenoid can be removed without removing carburetor. You will have to remove linkages on the left side first, then remove the two screws that hold the air vent cut solenoid. Instead of fabricating a cover you can just remove the plunger from the solenoid by rotating the plunger and pulling outward. The plunger has a keyway slot that holds it in the solenoid body. When you rotate the shaft under the spring it will align with a keeper and allow you to slide the shaft out of the body. You may have to pry or pull hard as the shaft is probably corroded or stuck in the body (that is why the solenoid burnt out). I used WD40 and worked the plunger in and out until it freed up. Once the plunger and spring are removed you can plug the stem that goes to the air canister. The previous post is excellent, as it is a permanent plug. By leaving the solenoid body in place you don' have to fabricate a cover. I also plugged the rubber line that went to the vent canister for good measure. This fix works great and will restore all power to the ACTY. You may have to put new spark plugs in as the old ones may be fouled from the rich mixture. Also, readjust carburetor settings to factory specs as you may have made adjustments while trying to figure out what was wrong. Correct idle and run settings will all return if everything else is right. Thanks for all of your posts as it really helps! I have attached photos that may help.
Glad I could help. You don't know how frustrating it was to track down what was wrong causing this problem. I completly dis-assembled and cleaned the carburetor twice, and tried all kinds of things before finding the bad solenoid. I believe the solenoids fail because of the alcohol in the our fuel. It degrades the seal on the stem and then the solenoid sticks causing the coil to fry.
Might try running Stabil (the new version for alcohol in gas). I think it helps counteract the effect of alcohol on rubber. I have been using it in my Honda tank continuously and the motor runs like new. A few months ago, before Stabil, it was harder to start. Now it starts on the first crank.
