Huasheng 49cc wont run without some choke

[Vducote]

The biggest issue with all motors used for motorbikes concerns "dirty fuel". About 90% of the time the coating around the gas cap loosens while removing or installing the gas cap.

To avoid serious problems, simply remove the coating around the cap, clean the tank, then install.

Another issue on the 49 CC HS motor is the location of the pilot jet. Often the jet is over looked and when stopped up can cause a lot of problems [choke must be on, won't idle, won't take gas, etc]. The pilot jet is located below the idle adjustment screw[black plastic], and is easy to remove. Simply remove the idle adjustment screw, and lift up the jet with a small screwdriver. Be careful to keep track of the small "O" ring at the base of the jet fixture. DON'T use a drill bit to clean the jet, instead use a piece of fine wire [I use part of a broken throttle cable].

It is wise to use carburetor cleaner in about every 5th or 6th tank of feul to keep the small passages clean.

Have fun,

Thanks for this info. Cleaned the pilot jet, (used wire from wire brush) and solved the no idle problem...

 

[Tom from Ironhorse]

On most hs142f engines there's a brass plug on the left side of the carb nearest the head. NOT the larger inset plug but the smaller one closest to the engine. Carefully drill out the plug with progressively larger drill bits starting with 1/8" or 3mm. Be careful to just drill thru the plug (its about 1/8" thick. After the plug is removed you will find an idle mixture screw. These are "factory set" and often are out of proper adjustment.

 

[Tony Gajeski]

"These are "factory set" and often are out of proper adjustment." You can say that again! My new motor started great when it was cold, but after warming up (10 minutes or so) it would die as I slowed to a stop. Taking the advice of the smart people in this forum, I removed the brass plug to gain access to the idle mixture screw. Lo and behold, the screw was set completely leaned out, fully clockwise! No wonder it wasn't getting any fuel! I used procedures found in another forum to adjust the idle mixture and found the motor ran great with the screw turned counter-clockwise 2 full turns (your result may vary). Thanks to all of you who share your knowledge and experience!

 

[Schatzimike]

The biggest issue with all motors used for motorbikes concerns "dirty fuel". About 90% of the time the coating around the gas cap loosens while removing or installing the gas cap.

To avoid serious problems, simply remove the coating around the cap, clean the tank, then install.

Another issue on the 49 CC HS motor is the location of the pilot jet. Often the jet is over looked and when stopped up can cause a lot of problems [choke must be on, won't idle, won't take gas, etc]. The pilot jet is located below the idle adjustment screw[black plastic], and is easy to remove. Simply remove the idle adjustment screw, and lift up the jet with a small screwdriver. Be careful to keep track of the small "O" ring at the base of the jet fixture. DON'T use a drill bit to clean the jet, instead use a piece of fine wire [I use part of a broken throttle cable].

It is wise to use carburetor cleaner in about every 5th or 6th tank of feul to keep the small passages clean.



Have fun,

I tried your recommendation and fixed my idle perfect. Unbelievable, and thanks so much. Did the trick!!

 

[CrazyDan]

I tried your recommendation and fixed my idle perfect. Unbelievable, and thanks so much. Did the trick!!

Removing the brass plug and playing with the idle till i find it's happy spot is the first thing i do when i fire up a new build.

 

[vctr79moore]

The biggest issue with all motors used for motorbikes concerns "dirty fuel". About 90% of the time the coating around the gas cap loosens while removing or installing the gas cap.

To avoid serious problems, simply remove the coating around the cap, clean the tank, then install.

Another issue on the 49 CC HS motor is the location of the pilot jet. Often the jet is over looked and when stopped up can cause a lot of problems [choke must be on, won't idle, won't take gas, etc]. The pilot jet is located below the idle adjustment screw[black plastic], and is easy to remove. Simply remove the idle adjustment screw, and lift up the jet with a small screwdriver. Be careful to keep track of the small "O" ring at the base of the jet fixture. DON'T use a drill bit to clean the jet, instead use a piece of fine wire [I use part of a broken throttle cable].

It is wise to use carburetor cleaner in about every 5th or 6th tank of feul to keep the small passages clean.

Have fun,

I was reading your blog from May of 2012 and it was very helpful to me and my situation. I'm new at this and it's my first build, I was having trouble with starting this engine changed some things and couldn't get it started until I came across your blog last night. So today I did just what you said and man my 4-stroke Huasheng 142f starts and runs like a 2 wheel Cadillac. THANKS

 

[John dimatteo]

how embarrasing

took air cleaner off and yes i was operating choke back to front . so i relased some tension off the throttle cable,reset the idle and it's running sweet.
thanks

Yeah I have a problem with my 4-stroke 49cc engine too it's the same kind I was going down the road fine with my choke off as usual as normal my choke was off and all of a sudden it just bogged down and quit now I can start it and it'll idle without the choke on but as soon as I give it gas it bogs down and dies but if I turn the choke on I can run down the road and it doesn't bother down and die I've already took the carburetor apart and you know I looked at it blowed air through it cuz I ain't got nothing else but I put it back on and it's still doing the same thing so I'm thinking about to get a new carburetor and I'm thinking to be safe I'm going to change the spark plug at the same time

 

[DieselTech]

Yeah I have a problem with my 4-stroke 49cc engine too it's the same kind I was going down the road fine with my choke off as usual as normal my choke was off and all of a sudden it just bogged down and quit now I can start it and it'll idle without the choke on but as soon as I give it gas it bogs down and dies but if I turn the choke on I can run down the road and it doesn't bother down and die I've already took the carburetor apart and you know I looked at it blowed air through it cuz I ain't got nothing else but I put it back on and it's still doing the same thing so I'm thinking about to get a new carburetor and I'm thinking to be safe I'm going to change the spark plug at the same time

It's probably got a air leak from the intake manifold to the engine block, get some carb cleaner, ether, something to that nature. Then spray around intake to block mounting area while engine is running, if a rpm change where you sprayed it, that's your leak.

 

[Wrench]

Yeah I have a problem with my 4-stroke 49cc engine too it's the same kind I was going down the road fine with my choke off as usual as normal my choke was off and all of a sudden it just bogged down and quit now I can start it and it'll idle without the choke on but as soon as I give it gas it bogs down and dies but if I turn the choke on I can run down the road and it doesn't bother down and die I've already took the carburetor apart and you know I looked at it blowed air through it cuz I ain't got nothing else but I put it back on and it's still doing the same thing so I'm thinking about to get a new carburetor and I'm thinking to be safe I'm going to change the spark plug at the same time

Seems like cleaning the pilot jet worked for others with the same issue.
get some carb cleaner, and poke a strand from a cable wire thru the jet
Just blowing through it doesn't work as good

 

[darwin]

Blast from the past post, 2011.