can't find an answer then ask here someone may be able to help!!

[onemanzu]

Norman, I have a question about how the choke on small engine carburetors work. I have the choke blade closed and the engine seems to run fine. If I open the blades at all at any point in time after I have the motor running, it dies. Am I wrong in thinking that the choke blade being closed means that the carb is at full choke? Should I adjust any of the carburetor? Is it getting to much fuel or to much air?

I guess I just need to know, is the choke blade being closed full choke or no choke?

Thanks for your guidance.

omz

 

[Norman]

You didn't tell me what type of engine or carb, not that it really matters.
If your messing with the typical bike engine take off the air cleaner the choke plate is under the air cleaner it's a plate with a sometimes small hole in it. the choke lever when moved will cover the carb's opening, this choke on for starting. Moving the choke lever the other way is choke off, the choke plate is not covering the carb's opening, used for normal running.
If your engine will only run with the choke full on then you have a air leak or a fuel starving problem. You will need to check for proper fuel flow and that the carb's float bowl is getting fuel. Could be your carbs. brass main jet stem has come unscrewed or something is wrong inside the carb. Unless you have the choke really off when your engine is running and you kill the engine with the choke on?
You need to also check that you don't have a large air leak on the intake to carb flange and at the intake flange to cylinder. Other air leak areas are the split seam on the crankcase, cylinder to crankcase gasket, and the seals on the end of the crank shaft.

 

[onemanzu]

My apologize, I had the motor in storage and was just able to get it out until recently.

The motor is a tecumseh h35. After lurking for a month, and finally being able to take apart the intake, I've come to the conclusion that it was a serious air leak. To the point that the gasket between the intake and carb was none existent. I'm ordering a carb rebuild kit due to the fact that its just an old motor and could use a little love.

Thanks for your ideas, I truly appreciate it.

 

[biknut]

Norm, could we go over the basic procedure to install the crankshaft, in the block of a generic china girl 80 motor.

Maybe this isn't a concern, but I can't see how to keep the main bearings from binding, when you force the case together so a couple questions come to mind about the assembly procedure of the main bearings.

1. How do you get the cases bolted together without the main bearings binding?

2. How do you center the rod in the middle of the bore?

3. Do you put the bearings on the crank first, or do you install them in the block first?

Thanks for any replys.

 

[StealthJPL]

Hi Norman, I bought a 49cc motor from Raw Motors a few months back. It ran fine for a while but now after pulling it apart a few times to make repairs, it will not start. It started fine at first, would not idle but rev up when I pulled the throttle. Now it does not want to fire up at all. I have searched out other sites but the only answer I can find is about the carb. The carb is fine though. The float valve is clean and so is the jet so I am sure that the problem lies elsewhere. I went on a 2 week underway with my ship and left the bike out in the open. Could the coil have moisture in it causing spark failure or am I missing something? Any help would be greatly appreciated and I hope that you can help me out as this is my only way to work. Thanks.

 

[chadlyw1]

I was just needing to know.. Does the mixture screw control the fuel or air, and which way is which?

 

[Norman]

for StealthJPL:::moisture will short out the magneto, kill switch,and etc.

Chadlyw1
Depending on what carb you have all of the china bike engines I have messed with, the idle screw only controls idle speed screw it in for faster idle speed. If buy chance you have 2 screws on the carb to play with one could be and idle mixture and the other could be the idle speed. On old lawn mower engines there were 3 screws idle, idle mixture, and high speed/wide open mixture.
You didn't say what kind of engine or carb, photo would be nice so we all can see what your playing with.

 

[chadlyw1]

Norman..Its a stock hs 49cc carb, yes it has 2 screws, 1 for idle n 1 for air fuel mixture...jus wasnt sure how the air mixture screw works (what happens when it turns in n and viceversa) ? Am I just adjusting the air? And is moving it in shutting the air off? Thanks Chad.

 

[rob.smith]

need a new intake gasket and dont wanna pay 20 bucks to ship the 3 dollar gasket. Would any auto parts stores carry these or what kinda material should i get to make my own?

 

[GearNut]

Any good quality fuel resistant gasket material will work fine.
| O'Reilly Auto Parts

 

[brett7777]

I would like to change out the head cover on my 48cc China 2 stroke, & put on a slant head cover (to get a little more clearance above the motor).
Is this a simple task? Does it involve simply taking out the sparkplug, unbolt the 4 nuts, remove the cover, & put the slant cover on?
Anything else involved or anything I should watch out for?

 

[Norman]

you'll probably want to replace the base gasket too. but all this is pretty straight forwards to do.
The reason for replacing the base gasket is they can crack/ leak causing your engine so do strange things, like idle high or die etc.
Look at the stickys I have somewhere on them I show the torque pattern and spec and a simple piston holding tool for getting the piston back into the cylinder with out breaking the rings.

 

[brett7777]

Thanks. Would I only have to take the piston out if I change the base gasket? otherwise just swap the head out, is that right.

 

[rob.smith]

I've had my bike for a little while now and i've been running a taillight off of the white wire for about a month now. lately i've have a loss of power and thought that the taillight was maybe stealing some of the spark causing the power loss so i unplugged it. took it for a ride down the street and it died on me. rode it back home and noticed i wasnt geting any spark, i tinkered for a couple days looking for the problem and then one day i plugged the taillight back in and boom i got my spark back. still very little power and low top speed but at least its running again. what could be causing this???

 

[Norman]

You must have some sort of a bad ground to the ignition system. so do a good look at your wiring. It's even possible you might have a failing cdi or mag coil, or a kill switch. If your bike is left out side in the weather then your going to have electrical problems sooner than if it's kept inside.
You might want to check the spark plug, and the plug wire, make sure there is good tight connections, any thing that looks like bluegreen poo in the wire is corrosion and will kill the spark, replacing the wire will cure it. Use a copper core wire, resistor wire isn't as good on these engines. You will also need to clean any of the corrosion out of the cdi spark plug wire hole. Dielectric grease on the connections will help stop the corrosion from coming back. Most auto parts stores sell the stuff, in a bind use petroleum jelly or plain grease.
Now for the spark plug, I prefer to run 0.017 to 0.020 spark plug gap. These engines ruin spark plugs, for me the cheaper the better. I don't see the need for the high tech expensive plugs, but it's your money so you buy what you like. Regular gas and a good syn. oil at 32 to 1 or 40 to 1 mix.
I probably didn't cover your wire problem real good but you are going to have to do some close looking at the wiring to find the problem. I threw out all the other stuff as all these can also cause the problem. So do one thing at a time then try the bike out. Don't do a bunch of stuff as you will not learn which one fixed the problem if it does.

 

[rob.smith]

Today when I was working on my bike I took off the exhaust pipe and it looked really plugged up inside. I ran some gas and clr through it for a while and got out a lot of gunk. Ran the bike without the exhaust and it ran great and actually idled for me. When I was putting the exhaust back on I noticed that the exhaust port on the engine is big and rectangular while the port on the exhaust is a smaller circle could that cause any problems? Put the exhaust back on and wouldn't idle and still didn't have much power. Could it still ne clogged and could that be whats killin my power?

 

[dakota47l1]

i have a fresh build and i am getting a power loss at low rpm...pulled the head and looked in the cylinder and i have light streaks on the cylinder wall.mix seems to be good on the plug.and it takes off at full throttle.but there is no in between.anyone???

 

[GearNut]

Is this a recent change in performance?
What type of carburetor are you running?
Are you trying a new fuel blend?
What spark plug are you running?
Stock or aftermarket spark plug wire?
Have you already checked for air leaks? Sometimes faulty crank shaft seals can cause this sort of performance loss.

 

[dakota47l1]

upgraded plug and wire,nt carb,break-in mix,no air leaks everything is tight have an o-ring in the carb.havend checked the seals.not shure how to get to them.and yes its a recent change.

 

[GearNut]

If you have not found any air leaks at the typical areas: Carb to manifold connection, manifold to cylinder connection, cylinder to case connection, cylinder head to cylinder connection, center gasket of left and right halves of case....then do check the crank seals. To check them you need to remove the magneto rotor and crankshaft pinion gear.
The seals are pressed into the engine case, located behind each respectively.