Honda clone motor won’t start hot.

[4570Man]

I’ve got a Lifan motor that’s actually been pretty good and has a lot of hours on it. Cold it’ll start easy with a couple of leisurely pulls. Hot it take several pulls and you really have to yank it fast. It’ll never start with an easy pull. I’m guessing a valve adjustment issue or possibly a bad plug. Any ideas before I blindly tear into it?

 

[tomplum]

Best to start with a new plug and verify that the carburetor bowl vent is open. Excessive valve lash won't create a hot restart issue itself. A valve that tends to stick may or a loose valve seat as well. Some had guide issues but you really didn't say what this really was. From your description, it could be flooding itself. Any signs of fuel in the air box or popping when cranking hot?

 

[4570Man]

I don’t think it’s flooding. I usually have to choke it for a hot start. It’s a Lifan brand.

 

[denchen]

Try checking the valve clearance. I`ve known some of these engines get hot and the valves are just touching so the valve is not fully closed.

 

[Diggin It]

The Kawi on my X-300 had different symptoms, but I finally found one of the valve guides had migrated out quite a bit. I was able to drive it back in without disassembly and it made all sorts of difference, though I don't know how long it will last. Might be worth looking at since you mention lots of hours run time.

 

[nyone]

Fuel, spark and compression is usualy all they need. Find out what one it dosnt have or has to much of.

 

[4570Man]

I wouldn’t be surprised if it was worn to the point of low compression but wouldn’t that give more problems cold?

 

[Stimw]

Check the valve adjustment.
If a true Honda knock-off it will have an exhaust valve centrifugal compression release on the cam.

 

[SPYDERLK]

I’ve got a Lifan motor that’s actually been pretty good and has a lot of hours on it. Cold it’ll start easy with a couple of leisurely pulls. Hot it take several pulls and you really have to yank it fast. It’ll never start with an easy pull. I’m guessing a valve adjustment issue or possibly a bad plug. Any ideas before I blindly tear into it?

Verify good spark when hot. It may be the igniter/electronic points starting to fail.

 

[MossRoad]

Have you tried starting it when hot at the lowest throttle setting with no choke? I have a 5hp tiller like that. And my Kohler Command Pro 25hp engine won't start well when hot unless I throttle it all the way back.

Also, as someone mentioned, it could be an ignition problem that manifests itself when warm. I have a chainsaw that starts fine cold and runs through a full tank. I refuel, and it wouldn't start until it cools off completely. Eventually found a cracked coil that would separate when hot and reconnect when cool.