I have a 16 HP Vanguard that seems to run great when not under a load. As soon as a load is put on it it starts spitting drops of fuel out the top of the carburetor and quits. If you run the choke about 1/2 closed it seems to run better but not as it should. I've replaced the carb and does the same as it did with the old one. The compression is within spec, I've checked valve lash and replaced all keys thinking it might possibly be a timing issue with no success. I rebuilt the engine about 1 1/2 yrs ago and it ran perfect for about a yr and then all of a sudden started running ruff and extremely rich blowing black smoke, fouling the plugs and wouldn't run under a load. At this point I'm lost so any help would be greatly appreciated!
16 HP Vanguard V-Twin
- Thread starter jmatt
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It might be your needle valve and seat gone bad, but you said you replaced the carb....
thats all that comes to mind right now. Model #?
thats all that comes to mind right now. Model #?
cruzenmike
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This is a confusing one. The governor is what controls the engines ability to maintain a certain rpm under load right? So if you load it up and it wants to sputter and quit, than it may be a weakened governor spring or governor that is out of adjustment. When you activate the choke you are enriching the air/fuel ratio. so this means that by enriching the air fuel ratio you're giving the engine a little more fuel to compensate for the load that's there but since the governor's not able to adjust the RPM it eventually just dies out. This is my best guess. by the way I do have an 18 horsepower vanguard in my exmark and absolutely love the engine.
I had the same problem with a 13hp twin Kawa on a Husq tractor unit. Several conditions come to mine. Bad ventilation through gas cap causing a vacuum on gas line flow. Loosen the cap and see if it improves, if it does replace cap or clean vent hole on the existing tank top. Check fuel filters for contamination and replacement. Check fuel pump flow. Clean or replace air filters. Unless your new carb is not functioning properly, you may find some of these suggestions helpful. Your engine is not getting enough fuel under load obviously.
cruzenmike
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If you haven't done so already, drain the tank, replace the fuel filter and maybe blow out the lines or replace. If that doesn't work check the hose running from the valve cover/head to the fuel pump for leaks. Could always replace the fuel pump while you are at it. Again, I think this is more of a governor issue but that can be an expensive fix, so maybe check the fuel system first.
The govenor is doing what's its supposed to its giving full throttle when you engage the pro but the engine can't take all the fuel. If the choke is about 1/2 closed it will keep running. When the govenor goes to full throttle ir spots fuel out of the top of the carb.