VH4D engine Zenith Carb

Hi all,

Quick question my skid loader carb spits a little bit until I close the choke a little bit, I checked my plugs and they are black and dry. I have tried adjusting the air/fuel screw with no luck at this point I am fine with closing the choke a little to use the machine however, am I damaging the engine at all by doing this? I plan to change the plugs will that make a difference? So when I close the choke a little and throttle up it sounds good and no popping at all .

That's definitely a "too lean" problem. Can it hurt the engine, certainly can... Too much choke, wash down the cylinders, dilute the oil, run too lean could burn a piston.

First, check the obvious, vacuum leaks. Get some spray carb cleaner, the flammable type, with the straw attachment. With the engine idling spray around the gaskets, any possible areas that could leak, listen for the engine speed to change.

If no vacuum leaks, check the float level, A low level will cause the mixture to lean.

Check for deposits in the bowl, partially blocking a jet or fuel circuit. Check the "off idle" circuit, the tiny hole beside the idle jet hole. Check them with the spray cleaner, spray it in, watch it pass through to the bowl. If turning the idle mixture screw has no effect, check this area carefully. There are simple carb theory illustrations available online.

If all checks well, consider increasing the main jet size slightly. Try to find one the next size up. If you can't find one, it can be drilled out, but be careful, they're hard to undrill!

Do one thing at a time, that way you'll know what fixed it and not be creating two problems instead of one!