I just got back from a work trip. Motor is rebuilt since it broke at last race. Won’t start. I tried two different spark plugs. Any ideas?
Do you have fuel? Check if plug is getting wet after windowing over.
Do you have spark? Wind over with plug out of engine to check.
As Mark is saying you need fuel and fire. I can see you are covering the air box, but does the line have fuel? It is possible you are flooded too but you would likely have gas dripping out of your carb. Checking spark can be tricky, especially in the sun. I have a spark checker that has come in handy for making sure there is energy reaching the plug.
This is the checker:
Remove the air box and place your hand over the carb inlet to choke it. Check engine and coil grounds. The engine timer lit up when you tried to start it. Assuming there is spark. You also may see your tack come alive while trying to start. Another sign of having spark. If choking did not produce fuel coming out of the carb, check the fuel pickup for leaks. Check the gasket behind the carb to see if it is orientated correctly. If the carb was service since the engine last ran, rebuild the carb again. Pls post up when the issue is solved.
At the 25 second portion of the video, there appears to be an open connector.
Thanks to all who take time out of your days to help newbies like me in these threads. It means a lot.
@Tony_Z, it appears the issue is fuel because the spark plug is bone dry and sparking well. When I took the airbox off, I heard fuel sloshing around in the bottom of the airbox. Why isnt the fuel getting into the combustion chamber? My understanding is that it’s getting blocked in the carb filters and I should rebuild the carb. Is that right?
As for the open connector you see in the video, that was for my killswitch. The killswitch never worked even when I first bought the kart from the previous owner, so my mechanic advised me to disconnect it. With the killswitch wire disconnected, the starter motor still spins, the spark plug sparks, and the hour meter turns on, so that leads me to believe it isn’t a problem that I disconnected it.
So this is a bit confusing. Spark is not the issue, unless something was not reassembled correctly at the spark is not timed correctly. If you have fuel in the air box its getting fuel into the carb. Its the compression of the motor that creates the pumping action that should draw fuel into the motor. So a few questions…
Was the carb rebuilt with the motor rebuild?
What work was done to the motor?
Have you checked the reeds?
Does the motor have compression?
Carb wasn’t rebuilt with engine, carb has 1 day of racing since last rebuild.
Work done to motor = top and bottom rebuild after it was damaged and lost compression (maybe because I ran too many hours before bottom end rebuild).
I did not check reeds.
I have compression tester for cars somewhere in my garage i think… but my mechanic would’ve tested compression after rebuild. Maybe I can check again if I find gauge and it fits kart.
Did the motor builder run it before he gave it to you?
A fresh rebuild should have plenty of compression unless something isn’t right. As a point of reference, I see about 180lbs on a compression gauge. I am focusing on this partially because your first clip the motor seems to be turning over really fast. In the clip you put your hand on the carb did you feel your hand being sucked towards the carb?
Yes, I did feel a strong suction. Does this suggest adequate compression? I think I threw away the tester when I was cleaning my garage 
.
I’ll ask builder if he ran it.
Might be worth dropping just a smidge of fuel into the cylinder via the plug hole. I’m surprised you haven’t even gotten a pop out of it so far.
Trying to think of other things that might stop fuel being pulled into cylinder…. A totally blocked exhaust possibly would do it.
I think you’ve already verified the reeds.
(Edit… nevermind the below… looking at the video you’ve got fuel at the carb for sure)
Did fuel come out of the carb when you placed your hand over it while cranking. It should have, very noticeably too.
Also did you prime the fuel line before connecting it to the carb? If not, it will take a good few turns of the engine while choked to draw the fuel from the tank
I would think so, if there is suction the fuel wants to be drawn into the motor.
I am with James that it is confusing you haven’t even got a pop or some indication that it wants to fire. Are you certain the plug is dry? This can be tricky to see on a new plug.
Does the motor guy have experience with the KA? I would question him further with your issue.
Looks dry in the pic I posted, right? Or is it supposed to look like that?
Builder has done 3 or 4 top ends and one bottom end on my motor.
I questioned him further yesterday and today. He hasnt responded yet.
someone mentioned it earlier but double check the gasket between the carb and the reed cage is in the right orientation. It has a pulse hole that leads into the case and if the gasket is oriented incorrectly it’ll block that hole.
I’ve had them be really stubborn on first start with drawing in fuel even if it makes it to the carb. Don’t be afraid to use a little starting fluid to assist. I’d put some 2 stroke oil down teh plug hole and circulate it a little give how much you’ve cranked it potentially without fuel. Meke sure the ring is lubed before you continue to trouble shoot.
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I was going to say this. Make sure your carb gaskets are oriented correctly and make sure the intake manifold is on the correct direction. I’m betting something was assembled incorrectly.
The other really stupid thing I’ve personally done…more than once, is pull the carb to clean / rebuild and for whatever reason put the carb back on the motor with the needles both completely closed and stand around and crank it trying to figure out what’s going on. Check to insure the needles are open on the kart.
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Ok I’m gonna try putting some oil and some fuel into the spark plug hole. What’s this ring you are referring to? Piston ring? How do I lube that? Do i have to take the cylinder head off?
Didnt work. Still no pops or bangs. I’m stumped. Compression test is the only thing i can think of to try next.
Did you take the carb apart and confirm that all the gaskets were oriented correctly and the correct gaskets were used?
@tjkoyen I rebuilt the cab myself. I might take it apart later and also take pics of the gasket on the intake to show you guys and y’all can lmk if you see anything wrong. Only thing i can think of with the carb is that I reused the same screen at the top because that screen isn’t included in carb rebuild kits.
Edit: here is the gasket behind the carb. I’ll take the manifold off too.
So you are putting fuel in the cylinder and it is NOT even popping? I would be inclined to try a quick squirt of starting fluid. Don’t use too much as this has a washing effect. This is why someone recommended a few drops of 2T oil.
I suppose it could be extremely flooded but this should be obvious on the plug and even then you should get an occasional pop. In all your videos we have not heard one.
The screen is just a filter and you are clearly getting fuel into the carb venturi.