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Craftsman DYS 4500 Model NO: CV492S SPEC NO: 27506 Kohler Pro 18hp OHV Hydraulic Valve Lifters Originally got this mower and it had an issue with the governor. RPM’s were through the roof and it ran wild and would die going up any kind of incline. I took the engine apart and found the governor sitting in the bottom, detached but in good shape. I reattached it to its proper location, reassembled. I then began to have issues with the mower feeling like it was not getting enough power, sputtering a dying. Eventually it got to the point where I am now. If the mower sits over night I can usually get it to start and run for about 5 seconds or so before it sputters out and dies. I understand this means that over time fuel is working its way up to allow this, hence I have assumed it is a fuel problem. I pulled the spark plug out and grounded it against the engine and confirmed spark. Instead of messing around with rebuilding the carb I went straight into just replacing it. I put a new fuel filter on, changed the oil, new oil filter. Put a new carburetor on, new spark plug. I replaced the grommet in the fuel tank and cleaned the fuel cap holes to ensure proper ventilation. Continued to have the same issues. I pulled the fuel line from the carb and tried to turn the engine over to see if it was a fuel pump problem. I had no flow so figured it was the pump. I replaced the fuel pump yesterday and still have no flow. I thought it might be an issue with the fuel line and I replaced the line from the tank to the pump as well as the line from the pump to the carb. STILL no luck. I am completely stumped at this point and am open to any suggestions before I drive it over to the engine shop Any ideas?
My dad and i completely took apart one of these this summer on the driveway, did a whole paint job in a nice blue too. We have the briggs&stratton 18hp model. little older. You have done an excellent job troubleshooting the issues! i don’t blame you for just replacing parts, we felt like it, but it was fun to take it all apart too - the carburetor is the main problem with these engines . We watched some videos on you tube to lean about it. Now that you have replaced the pump, the fuel line, and inspected the fuel tank, the only possible thing it could be is that the pump is not getting power or not ‘turning over’ properly - meaning many liquid pumps need to be ‘primed’ - sometimes even a small air bubble in the impeller will stop the whole show. First what i would try is test that the fuel pump is working - as you said i believe you have, but its going to be 12v so maybe mock up a wire to it directly from the battery, and put the end of the fuel line in a gas tank, turn it on and off repeatedly, moving it around/upside down - and tapping it against the engine - try to make sure any air is out of it, you may experience it blasting out fuel all of a sudden so be careful. one other suggestion, is search youtube for this: “Craftsman riding lawn mower - aligning Valves to top " We had to do this twice, the first time i did it wrong, and the second my dad showed me. you will see a few videos about this, some better than others, HINT: use a pencil or something in the spark plug hole to know when the piston is at the ‘top dead center’ - also i would recommend getting for-real gap calipers, they’re like 5 bucks from Crappy-Tire here in Canada. That will make your starting smooth as silk :) If this helps, please report back.
i had the same issue i pulled the fuel line off the pump and made sure it spit fuel when i cranked it over it did i than tried to blow through the line going from the pump to the carb and could not get any air through so i took a hand air pump and put the tip for pumping up an air mattress on and it fit tight into the fuel line i pumped in a little air and could feel something pop through problem solved runs great
Your main jet needle is sticky. Check the fuel bowl solenoid operation. Apply 12 Vdc and observe needle retraction. The fuel pump runs off engine vacuum. There’s a third port for that. Fuel in & out are the other two.
I had the same problem until I located a screw under the gas tank and start turning it every time I started the mower and now it run great it looks like a small cup with a screw in it
Im still thinking its the carburetor something is not right with new one you put on to me sounds like a carburetor are all your gaskets good on carb to engine? Try a different carburetor at night the gas is trickling into carb thats why it starts but then dies let me
Hey all - just an update (I wish I could tell you I got it running and what the problem was but I ended up moving and having to sell the mower as-is. I can say I left with a lot more knowledge than previously - hopefully the next project won’t give me as much trouble! Thank you for your suggestions and help.
These models have a common problem that the air intake flap in the carburetor tends to break off; so the choke fails to work. You need to change the carburetor.
