Model pp4218 throttle stuck open

If your Kubota ZD28 is starting at wide open throttle with black smoke coming out of the exhaust and the throttle is not working, it could indicate a problem with the fuel system or throttle linkage.
Here are a few potential causes to consider:

1. Incorrect injector pump timing: If the injector pump was not installed correctly or the timing is off, it can cause the engine to start at full throttle with black smoke. You may need to re-time the pump to resolve this issue.
2. Clogged fuel injectors: If the fuel injectors are clogged, they may be supplying too much fuel to the engine, causing it to run at full throttle with black smoke. You can have the injectors cleaned or replaced to fix this problem.
3. Faulty throttle linkage: If the throttle linkage is not properly adjusted or is broken, it can prevent the throttle from working properly. Check the linkage to ensure it is properly connected and adjusted.
4. Air intake system: Check the air intake system for any blockages or leaks. If the engine is not getting enough air, it can cause it to run at full throttle with black smoke.

It's important to address this issue promptly, as running the engine at full throttle can cause damage to the engine and other components. If you're not comfortable diagnosing and fixing the issue yourself, it's best to take your Kubota ZD28 to a qualified technician who can diagnose and fix t

didnt specify the make and model so generic answer ---check fuel mixture is correct --check the filter in tank is not plugging up--look for damaged / crack in fuel feed lines-look at spark plug --carb may need cleaning --exhaust port may need cleaning

I believe that is the governor spring you are referring to. YES it needs to be replaced, before you sustain permanent engine damage.

have you left the choke open ? this mixes more fuel to the engine upon starting but will stall it if left open too long . check your fuel filter too it may be full of debris.

Make sure the fuel filter, air cleaner, and muffler are not plugged. Make sure the fuel lines are not decayed or other damage. Turn H and L jet screws CW to stops (lightly), then back CCW 1-1/2 turns each. This is a basic setting that should allow the engine to start and run. Allow the engine to warm up, then pull the throttle full on. Adjust the H jet screw CW until the engine starts to speed up. Correct adjustment is when the engine 4-strokes at speed unloaded, but immediately 2-strokes when cutting. Release the throttle and adjust L jet screw CW until the engine idles fairly well, but allows the engine to 'follow the throttle'. If you go too far, the engine will 'gasp' when throttled. Hope this helps!

Try Adjusting The High Speed Jet.You Can Do This By Turning It IN Or Out Until IT Smooths Out.If That Don,t Work The Carb Needs Too Be Rebuilt.

Look at eReplacementParts.com and the parts diagrams or ToolPartsDirect.com - Your Tool Repair Supply Store.

If you need more help come back.Post / thumbs / testimonial are welcome!

Your bike will only run at full throttle if your cable or main jet needle are stuck in the full throttle position .Take your throttle cable off and check that its freely working inside the outer caseing .

The engine speed is controlled by a governor and throttle position. There is a spring that holds the throttle (butterfly valve) against the slower position. When the motor is under load' the governor exerts force to open the throttle position. Make sure that all of the components are clean and not binding. Look for a broken or disconnected spring. It is also possible that the governor is stuck in the demand full throttle position.

check the throttle position and make sure that its not stuck in the open position if its ok check the internal components of the carburator inside the flapper may have fell off , its usual held in place with a screw or 2. check the govenor and all springs