what's wrong with my carburetor?

Jon Dalton /

while my Honda PC-50 was sitting for a month after my friend crashed it, we switched the carburetor with the one from my friend's newly acquired pc-50. So I know this engine runs with a good carburetor on it. It seems to choke out as soon as the rpm's get up into the cruising range (with or without load). Originally we thought it was the seal between the main jet ,basically an O-ring, causing extra fuel to flow past the jet. We fixed that with another O-ring, then we tried epoxying the jet to the carb to be absolutely sure it was sealing, and no difference. I just found out the only way i can make it go is to remove the whole cap and slider assembly from the carburetor. It goes like crazy with the throttle removed, faster than it ever went before, but i have to control it by covering the hole where the slider goes with my thumb. It's like an on/off switch like this, it's either to the floor or idle, and there is a delay when i put my thumb on the whole before it starts slowing down.

Re: what's wrong with my carburetor?

don't epoxy things in a carb ... ok ... other than that ...

the carb on the other pc50 may not have been identical. it sounds as if they had (at least) different jet sizes. check them out to be certain.

Re: what's wrong with my carburetor?

Ron Brown /

Jon,

The only way I can imafine this happening (and I have never seen your carb), is either the float is not working so the carb is permanently flooding or possibly your enrichener, for cold starting is on all the time.

Don't try to run it this way or you may do some severe damage.

Ron

Re: what's wrong with my carburetor?

Crisis--Cincinnati /

Jon, Did you switch the whole carb out, or just the bottom part? If you just switched the bottom part, and left the choke slide and needle, spring, from the old one, it is possible that the new carb is bigger, and you will need to use the same choke slide and needle that it originally had. Just a thought, because that is what happened to me when I switched out my carb. I didn't feel like taking the throttle cable off, so I half assed it, and tried to use the same slide and needle from my old carb, on my new one. I had the same problem as you, when I did this. My bike idled at Mach 10 and ran like shit. There was too much fuel getting in because the choke slide was not big enough. There's my two cents.

Re: what's wrong with my carburetor?

Jon Dalton /

thanks a lot guys. i'll check the float and the throttle slide. It is an identical carb, and the whole carb was changed except for the throttle slide, cap and needle. The jet looks the same, or at least very close. The epoxy didn't make it any worse, but it sure didn't make it any better.

Re: what's wrong with my carburetor?

the carbs may look the same, but be different numbers (like a 14mm or 15mm carb). check for that in detail. and jets should have a # stamped on them. they all look the same, but the # is the key. if they're not the same # ... that's probably your prob.

Re: what's wrong with my carburetor?

Crisis--Cincinnati /

I bet that your slide is too small.

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