I have a 200cc Viva quad and I have cleaned the carb, properly set it up, new spark plug and a few other things and I can not seem to get the "surging" to go away from the idle. It idles high, goes to normal for a bit then does it again all of the time. Sometimes I am lucky and it does not dot it as often but it is still there. ANY suggestions??

Thanks!

 

make sure you cleaned out the little holes at the bottom of the pilot jet. Mine did the same thing until I ran a thin wire through all the orifices. Don't know what carb you have but most of these are very similar. 1 main jet and the low speed or pilot jet. In the photo the large one is the main and the smaller one is the pilot and is located right beside the main. Any blockage or damage to that low speed jet will likely cause idle problems.

 

I'm an electrical guy, but this sounds like carburetion to me too. So I would check the jets as Sidewinder747 said.

Do you by chance have an electric choke (also called a bystarter valve)? In other words do you have electrical wires going to your carburetor? If so another possibillity is an intermittent choke causing the fuel ratio to alter causing surging at idle. This happened to me when I only plugged a connector in halfway making intermittent connection to the choke. I spent the whole afternoon chasing this before I discovered my stupid mistake.

 

Nope.. I have a cable choke and I made sure to thoroughly clean the carb, jet holes and all. I had this problem so that is why I took off the carb to clean it but it didn't help..

I did adjust it a bit (including raising the needle jet by 1 notch) when I put it back on and got it to run better but the surging is annoying!

 

2 things:
1. i presume the slide is installed correctly, right?
2. have you checked for vacuum leaks around the carb?
just some thoughts.....

 

1. If the slide was in 180 deg. off, it would rev to the moon.. So yes, it is in properly ( I made sure it was in with the "curve" in the proper position)

2. I am checking for leaks as soon as I am done writing this. I will post results if I find anything..

 

I had one that the gasket under the slide got pinched and didn't allow the top to seal and caused a similar problem. The one with the pilot jet problem had a very small piece of dirt inside the smaller holes in the bottom that I could only see with a 10X magnifying glass. Ran a thin wire file through the holes and that cleared it up. Nowadays I eliminate any possibility of jet problems and other sources of air before I look at other things. Not a fan of electric chokes and get rid of them first thing on anything I buy. believe in the KISS principle and how much trouble can it be to reach down and manually adjust the choke. One less thing to fail.

 

I did find the problem. It was the intake tube bolted to the motor, it didn't have a gasket in there so I made a gasket for it and bolted it back on and broke it Mot#*rF*#k@r! Good thing I have 2 . I will get the other one fixed with some JB weld in the meantime..

 

Ever try this stuff?

Dura Fix Aluminum Welding Aluminum Brazing Aluminum Soldering & Repair Rod

That and a little hand held gas torch and good as new. They sell the rods at Harbor Freight. I think its about $13-15 bucks for a tube of 10-12 rods. I got some a year ago and have only used a couple of rods fixing stuff around the shop when I get ham-fisted with aluminum. You can actually make a decent looking weld with the stuff and if you can't don't worry you just grind it down anyway. Stuff works, especially on intakes and things like that.

"Sidewinder's hot tip of the day"

 

Is this what you are speaking of at HF? Aluminum Welding Rods - Pack of 8