I'm working on my Craftsman mini cultivator. It has a 2hp 2-stroke Tecumseh engine. I've replaced the carburetor 3 times, along with all of the gaskets. It will start with a squirt of starter fluid, and will run great! It will continue to start on it's own within an hour or so, but after it has rested for a couple of hours, it simply will not start without a shot of starter fluid. Since I'm on my third carburetor, and have cleaned all 3 of them thoroughly several times, I'm at a loss! Compression is right over 100psi. Spark plug is new. Gas cap is not clogged. I've cleaned the coil and flywheel magnets and re-gapped it. I got to thinking that maybe there was an obstruction/dirty filter or something in the tank. The fuel line connects to a little nipple at the bottom of the tank. I tried to look in there with an endoscope, and could only see what looks like some sort of a filter screen. Couldn't see much more. Don't know where to turn! Any thoughts? Thanks, in advance, for the help!
#2
sgkent
does it have a choke? Use it. If it has the primer bulb try using it one, maybe 2 squirts.Your problem is getting the correct fuel to air ratio. In my experience with small cube carbs, they are good for maybe one, maybe two seasons. Often the diaphragm flaps that work as a fuel pump warp (your part #62 on the diagram for yours). I had a Mantis with that carb that I could fix in June, run perfectly, drain the fuel from it, put it away and in November be back to the same old problem when I went to use it again. Replace the carb, run great and in March or April it was goofy again. I'd just use a tiny squirt of starter fluid to start yours but not a lot, or keep a spare carb on hand. Only takes about 10 minutes to replace them when you get good at it.
Thanks for the reply! It has a lever choke, but no primer bulb. I keep a stack of diaphragms on hand, but didn't think to change part #62. I'll give that a shot! Thanks, so much!
Have you checked both crankshaft seals? If they are old or stiff you may have an air leak, creating a lean starting mixture. After they warm up they may seal, but then harden when it cools down.
Just pulled the crankcase. The gasket had a tear, but it was hard to tell if it had been previously torn, or if it tore when removing the piston housing. At any rate, I removed the old gasket, cleaned both surfaces well, and then put some high heat gasket maker on. It's all back together, but I'll have to wait until tomorrow to try it out. I'll keep y'all posted!
I only checked the upper seal. It seemed fine, with no wiggle room. Is there any other way to check the seals other than with visual inspection? Also, it looks like the seal might be parts 20 and 44. The image is not very clear. Does that look right? Thanks!
Keep it simple. Get a bicycle drink holder and bolt it to the handle. Keep Quick Start in it. Done.
#11
sgkent
as stated in the last post, keep the starter fluid around or find the cause. The air to fuel mixture needs to be richer when the engine is cold. It sounds like either the choke or fuel primer bulb isn't working, or being used incorrectly. I had a carb on my edger that took maybe 20 squirts to get the engine to start when cold. Rebuilding the carb did not help. Then I replaced it with a new old stock one and it starts first pull on a couple squirts of the primer. Sometimes things just get worn internally in the carbs. If yours starts with a couple primes but dies over and over, that might be the fuel supply system. On many of the old carbs that is a small diaphragm that has a flap on it that acts as a check valve in a fuel pump. When they warp they don't seal. No seal, no fuel, so no run.
Make sure the gasket between the carb and intake block is lined up properly for the pulse port from the crankcase. Use only non ethanol fuel mix or Trufuel 40-1 on these little engines.
And using starting fluid in a 2 cycle engine is inviting disaster. It washes the oil out of the engine or dilutes it. It’ll cause more problems than you need.
In fact, I use ether to clean the oil and dirt out of air filters on chain saws. Try it and watch what it does to the oil.
