I purchased a used 2005 Eton 150 Viper that does not idle. You have to keep playing with the throttle to keep it running. Once its at mid range to wot it's fine. Runs great at top end. It seems to be running rich and loading up at idle, even changes speeds. I installed a new plug , carb and checked/ cleaned the exhaust spark arrester. Still does the same thing. Spark arrester was black along with plug so it is running rich at idle and low speed. I thought it would be the carb but that wasnt it. Ant suggestions?

 

If it is running rich, it can only be carb, choke, or air filter. Choke not coming off, wrong idle jet or badly adjusted, float level too high, or partly blocked air filter. However faulty ignition also causes a sooty plug as, if the engine doesn't fire every power stroke, unburnt fuel builds up and causes a rich mixture when it does fire.Change the plug just in case it is this, but my guess is you don't have the carb set right.

 

Will give it a try again. It's just strange new carb presents same condition as old one. I forgot to mention original air box was replaced by original owner with aftermarket air filter (looks like K & N knockoff). Maybe carb has to be rejeted? What size jet is original and what should I try if anyone knows? I also noticed the fuel recovery hose that I'm assuming went to air box is not connected to anything. Choke is definitely off. Spark checked with inline spark tester, looked consistent. I'm waiting for fitting to check compression just to make sure as well. Thank you for the input.

 

I also noticed engine really doesn't change speed while trying to adjust air/fuel mixture screw. It doesn't have any real noticeable effect. I ran it with air cleaner off, same condition.

 

Not sure what you mean by fuel recovery hose. Breathers usually just go upwards, and the drain from bottom of carb dangles down so, if the float chamber overflows, fuel runs down to the ground. I missed that you had changed the carb, Try cleaning out and re-fitting the old one but, as you wrote, two giving exactly the same symptoms is unusual and would indicate something else wrong. Check valve clearances, but I would be beginning to suspect an ignition problem.

 

OK, another new carb, new spark plug, new air filter, new gas. Same problem. Compression test 125 psi. Spark seems fine as well. Guess I'm pulling the valve cover (after steering post removal to gain access) and taking a look.

 

Adjusted valves, intake was alittle tight. Check timing marks all good. Still have same condition. Does anyone know what the two green wires with bullet connecters coming out of the CDI internally are for or where they should be wired to. It looks like someone might of connected one to ground and another to a wire that looks like it goes into crankcase? This Eton seems to be one of the only ones with these 2 extra wires other then the two modular plugs. I also see its over $100 online.

 

Most Chinese and Taiwanese makers use Honda wiring colours, so green wires are almost always earths. Sometimes the trigger coil for timing has it's own return, so it isn't earthed to engine but directly into the CDI, it could be this. Though Etons were always a bit different regarding ignition circuits, most Etons are earth to run on the kill switch, most other makes use earth to kill CDIs. This is the reason standard CDIs won't work on them.