Craftsman DIY 4000 will not start when warm

I own a 98(?) Craftsman 4000 with the B&S 18.5 HP OHV Intek Plus engine. It usually does not sit long as I use it to blow snow with also. Recently, it started acting up once I've run it for a while. I just replaced the spark plug and tonight it started instantly. I mowed most of the yard, stopping a couple of times to dump grass. Each time it started perfectly. The last time, however, it started, then sputtered. The engine would run up to speed, then sputter and almost die, then repeat. I saw it was low on gas, so I added some. Then it would not start at all. The starter spins the engine fast, but nothing. I pulled the plug and am getting spark. I pulled the fuel line and as I cranked, fuel came out. When I removed the air filter, the inlet port to the carb was wet. When I cranked it then, some gas sputtered out of the port. I'm thinking maybe flooding. I noticed a tube coming from the oil dipstick tube to the fuel pump and assume that is what drives the pump. I then pulled the dipstick and turned the engine over - mistake. Oil splattered out of the dipstick tube. So, it runs great for about 30 minutes, then gives up the ghost. Any ideas would be greatly appreciated.

 

Remove clean and rebuild the carberator.
Use real carberator clean, do not just try and blow it out with air.

 

Sounds like the carb needs cleaning and you may have a problem with the needle/seat, possibly requiring replacement of the needle. If this has a nikki carb, it may need an o-ring where the plastic insert meets the carb body above the inlet needle.

 

Thanks, I'll try that this weekend and see what happens. Any chance the fuel solenoid could be involved? I don't know what that thing does.

 

The solenoid won't make it flood. It could cause it to get no fuel, but that's all.

 

So, I took the carb off today. It's a Walbro and I think I found a kit for it. I find B&S part number 697241 as the correct rebuild kit. The bowl had flaky rust in it, but everything else seemed ok. I also took the intake pipe off the head and the entire inlet port was full of gas. I sucked it all out with a syringe. Any chance of that messing the engine up? I will check our local parts store for the kit, otherwise I can get it from Amazon. Still curiuos as to why it ran great for a bit, then acted up. It did that several times over the last couple of weeks.

 

So, I got the rebuild kit and a new bowl. All went well and once I got it back together, it fired right up. The next time I mowed, it made it about 40 minutes, then started to sputter again. I opened the hood to see if the plug wire might be sparking, but it was not. On every sputter, the exhaust came out black, so before it died, I reached down and kinked the fuel line closed. The engine immediately leveled out. I held it closed for about 30 seconds then let go. It ran for about a minute, then started sputtering again, so I kinked the line again. Again, it leveled out. After holding it for some time and letting it go, the problem did not happen again. I think this shows that there is too much fuel getting in somehow. Should I replace the fuel pump?

 

Check the float to see if it is sinking. Shake it and if it sloshes it has fuel in it, replace float if it has gas in it, also does it have a brass seat where the needle goes? If so polish it with q-tip and a good brass cleaner, I use a variable speed drill.