Gas spraying out of HS carb

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darkcobra94

New Member
I have a Hua Sheng f142 49cc engine, I used to use it on my bike before getting a 2 stroke. I recently decided to fix the engine up, i tried doing a bearing conversion for the one-way bearing, and I had to replace the entire crankshaft.

I replaced the crankshaft, used the permatex for the crankcase gasket. I installed the magneto coil and the pull start. I also cleaned out the carburetor.

Before I replaced the crankshaft, the engine ran fine.

Now, as I pull the pullstarter rope, gasoline seems to spew out of my carb. It does not start when I spray carb cleaner in it also. Compression seems fine, and the spark plug is making a spark. What could be causing the gas to be coming out?
 
When I say I tried to do the bearing conversion, I ground the shaft too much and just decided to replace it with another 5/8 shaft. I have a Grubee 4G transmission that I will put back on once the engine runs.
 
Is the float stuck on the carb? I don't have personal experience with the carb itself, but if gas is literally spraying out the carb I would assume it would mean it is flooding the engine and the carb itself.
 
Is the timing right? Did you get the cam back in how it goes? You have to align the timing marks on the cam and crank. If you know that, sorry, I'm not talking down to you but some folks don't realize how critical the valve timing is.

Tom
 
I don't know what you even mean, I've never rebuilt a 4 stroke engine. I have the intake valve at .004, and the exhaust valve at .006 . I just replaced the spark plug and still nothing. Took apart the carb and the float seems fine. What do you mean about the timing? I took the entire engine apart, then put the new crankshaft back in, and put it back together. I'm quite lost, sorry. Any guidance? I will do many searches! But thank you for the responses!!! :D
 
You were correct! It was the timing. Thank you!

I watched a youtube video on how to figure this out.

https://www.youtube.com/watch?v=6279V__l3pw
(for anyone out there looking to rebuild the Hua Sheng)

On the cam wheel (plastic wheel), there is an arrow.

On the metal gear on the crankshaft, there is a little dot. I matched those up, and bam!

Now I get to loctite every bolt and clean it up, and assemble it tomorrow, then I'll be getting the belt for the transmission, and a wide crank pedal kit!

But if only I remembered where this one washer went... :)

I'll upload pictures tomorrow for future reference!
 
Did you make sure the cam was installed in the right position? There should be some dots or so,e kind of marks on the crank and the cam gear that need to be lined up with each other or the valves won't open and shut when they're supposed to. Same goes for the ignition timimg, does the magneto have slotted mount holes? If it does then that's your ignition timing adjustment. Both the cam and ignition need to be properly timed with the crank or you'll end up with a very poor running engine or it may not start at all. This is an easy fix if you got it wrong. Another issue with improper cam timing if the engine has overhead valves is that the piston can hit a valve and bend it, and the only fix for a bent valve is to replace it. This is only a problem with overhead valve engines that are considered interference engines, but can cause a lot of damage like bent valves, cracked pistons, or even bent rods, it can also bend a push rod so this setup is critical on interference engines. I'm not sure if the hs engines are interference, flat head, or ohv tho so don't worry on that part unless someone who knows tells you it is...
You should be able to check the cam timing by removing a side cover to see if the marks on the gears are lined up properly. If there are no marks you can still check by making sure the valves are completely shut at tdc, but almost every modern engine I can think of has a way to ensure cam timing is set correctly before assembly.
 
I really appreciate it! I just have to go back tomorrow and loctite + permatex the side cover, and clean everything up. Also, laugh at me, I'm waiting for my intake manifold to arrive, and I need to order gaskets.

I trashed this engine when I got my 2 stroke, thinking that I would never use it again!

I had to resolder a new spark plug boot/cap on it, and hot glued it to seal the solder.

After sealing everything up and getting gaskets, it'll be good to go. I just need to get a new belt for the 4G and a wide pedal crank kit :p
 
Haha... I think we've all done that before... new engine so time to see how much abuse the old one can take before it grenades... but at least most the time they're still fixable...
 
Glad it's working out for you. Just a word of caution re: Loctite. Don't use the red stuff, on anything! The blue will hold sufficiently and you won't need heat or risk damaging something if you ever need to disassemble it again.

Good luck.

Tom
 
I agree there... the red locktite is too strong and you will snap bolts or studs trying to take them out later... the blue is plenty strong enough on these...
 
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