My Cub Cadet Z-Force 44" with a 20hp Briggs and Stratton has an issue that's got me stumped. The engine will crank but will not start without gasoline being sprayed into the intake. Once it starts, it achieves full throttle and idles with no problem for hours. If I shut it off for a split second, it will not start without manually introducing gasoline into the intake.
I stripped the carb down today and did a complete overhaul kit on it. The inside of the bowl/carb looked brand new. All the jets were clean and shiny, but I still cleaned everything and used up two bottles of carb cleaner. Once back together....same issue. I pulled the fuel pump outlet hose and put it in a bottle. When I started cranking it was putting out gasoline. (I'm not sure what the pressure should be though.) I am familiar with how the vacuum operated pump works and also tried this same procedure with the gas cap off so as to check any possible venting issue that may hinder the pumps ability to work. Nothing changed. The vacuum hose appears to be in really good condition as do the fuel hoses. I pressurized the tank to the point of it venting, shut off the fuel valve, reconnected the hoses, and opened the valve back up. The built up pressure enabled the mower to start one time, but I wasn't able to repeat this later. It's obviously a fuel delivery problem seeing as to how it runs once started. I also don't believe it's the solenoid whereas it operates correctly when voltage is applied and again the engine runs PERFECTLY once started. What is the best way to troubleshoot this problem?
I would check to see if the carb is choking first. If it is u may have a hot restart prob in the ignition coil
#3
pugaltitude
Depends on your model, type & code but sounds like fuel not being pulled into cylinder.
Could be valve clearance, or valve seating but that would probably cause no running and iv even seen head gasket causing this problem.
Is there fuel and excess oil being backfired into air filter?
I would give this a try to see if we can isolate the problem. Using the palm of your hand, completely close off the carb air horn and see if by hand choking it, if it will start. If it does start, I would check to see with the choke is fully closing and then I would raise the float level slightly.
