Running fine then suddenly stopped. could not get it to start back up, so i took it to the local shop. they cleaned carb and verified it had plenty of spark. they said maybe the carb was bad. i installed new carb and still can not get it started. please help...echo pb 251

Main jet is clogged - clean/replace carb

you may have an air leek on carbs or its running too lean

change the spark plugs

4700 not a lot of miles. This motorcycle needs to run. It will be rough until you can get the carb cleaned. I would keep doing what you have been doing for a while. After a couple hundred miles if it doesn't improve, you might want to consider having the Harley shop give it a good tune up. Check the plugs ...

check the carburetor. If you have a stiff diaphragm then it won't run.
I have seen them that behave just like that. They will run fine, turn it off for a few minutes then they won't restart. WD40 isn't going to get it to run either, try a small amount of mixed gas right into the carb. It should run for a minute until the gas you put in runs out then die. If it doesn't run then you have a bigger problem

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When you say it will not rev up to full speed, that sounds to me like a blockage either in the spak arrester in the muffler outlet, or the exhaust port is blocked, or the muffler itself is blocked.

I would start with pulling the carbs, and cleaning the jets. run a wire from a wire blush , so you dont damage them, thru them, with some carb cleaner. should be fine after that. pull the jets and clean then, dont just spray carb cleaner thru them.

It may but don't count on it. Sounds as if the carb needs cleaned out. The carb probably is gummed up and dirty causing the problem. You can do this yourself if you are comfortable with carb work or take it to your local mower shop to have it done. the repair is usually inexpensive to have done and if a shop does it they fine tune the carb as well.

I would take a close look at the valves, if you are sure the carb is entirely clean. (Accelerator pump and everything)
A closed up exhaust can harm an exhaust valve.
Start with a compression test.
Good spark?
Is the plug wet?

I had the same problem. I took off the carborator and cleaned every opening I could find. As I was reassembling it, I noticed the holes in the bolt that holds the bowl on were plugged. I hadn't notice that fuel flows through the bolt to the carborator. I cleaned them out and the mower started fine. I suspect it was that all along. I would try cleaning out those holes before you take off the carborator.