Hello, I have a Snapper 33" LT140HBBV with a B&S 14hp model#287707. Problem is the mower is taking a very long time to start, I have to crank it for 20+ seconds. When it catches it will make a few loud bangs and put out a big puff of smoke. Once it is running it sounds fine and will start immediately once it is warmed up. I did adjust the valves over the weekend but it didn't seem to help, it actually seems to take a little longer now. I thought maybe it was a choke problem so I watched the levers as I moved the throttle up and it is hitting the choke. I didn't verify that it was moving at the carb though. Not sure what to try next, any suggestions? Also, I verified the fuel filter is good.
This could be a fun one to track down. My thoughts are going about 10 different directions with this one. Let start by confirming fresh fuel, and that you have spark under compression. That will require an inline spark tester that connects between the plug wire and the plug. Also when was the last time the plug was changed. May not hurt to try a different spark plug.
From there I am thinking compression issues, which could include head gasket or valve issues. Another thought is the carb is leaking into the intake, but not with a large volume like most that contaminate the oil but just enough to cause a flooding issue. May try starting without using the choke initially. maybe after cranking a few seconds remove the spark plug and see if it is wet.
Let me know what you find. Any other information that you can provide like what color the smoke is at start up may help narrow things down somewhat.
Great, thanks so much for the info! What color would the smoke be if it was flooding? I think that may be what's happening; when it starts, it spits out of the muffler for a second. Also noticed today while I was checking the air cleaner, there was a puddle of gas in the bottom of the tube that goes into the carb.
I'll try a new plug also, should have done that already. Put a new one in last year but maybe it's worn out already.
If you are getting gas puddles in the carb,then that confirms that the carb is leaking. Make sure to check the oil level, and to smell it for gas contamination. Flooding would create black smoke. But you could be getting blue smoke at startup if the gas isn't really flooding, but is washing down the cylinder walls of oil
I suggest turning the gas off a few seconds before stopping the engine and see what happens. NO shutoff valve? Pinch the gas line with Vise Grips. IF this helps, add an inline shutoff valve and use it when the engine is shut off. A shutoff valve is good insurance anyway.
OK, we're getting somewhere! I went out this morning and pulled the plug, it seemed a little wet. I put it back in and started it up, as usual, a couple bangs and a big cloud of smoke, I would say between white and blue smoke. Shut it off after about 20 seconds when it settled down and clamped the fuel line. Pulled the plug out and went out and bought a new plug, oil and shut off. This afternoon I changed the oil, it smelled like there may have been gas in it but not really sure, put in the new plug and installed the shut off valve. Next I turned the gas on and started cranking, after a second or two I hit the choke (forgot to do it first) and it started right up, no banging and no smoke!! I realized after I started it that I made two changes so I couldn't be positive which one worked, but I can leave the gas on next time to verify it. To me, the flooding carb makes the most sense. If that's the case, do I rebuild the carb? or just remember to use the shut off? Thanks for the help!!
Dozens of B&S engines are ruined by gas contaminating the oil. A gas line shut off is good insurance as I said previously BUT you have to use it all time. The one time you neglect it is when carb will leak. Reminds me of the elderly widow woman who said, "But I just went in for a cup of coffee," when she destroyed her engine after I had warned her about it.
Are there any special tools needed to rebuild the carb? It looks like there are two kits, one with the basics and one with everything. I've done a snowblower and a chainsaw but that's about it. I'm thinking maybe I'll just replace it with a new one when I get around to it, cost isn't that crazy, $107 on amazon.
After reading a lot of other threads on the forum I think I came up with a plan. Remove the carb, clean, install new float valve, seat and oring. Sound OK? I have an ultrasonic for cleaning my clock parts, it has ammoniated cleaner in it. Does anyone know if ammonia will harm anything in the carb or the aluminum? Thanks again for all of the help!
All you really need is the float needle and seat IF that comes with seat. There is a good chance it will leak afterwards anyway unless you change the fuel line and do a really good job of cleaning out the gas tank. It is said that ethanol causes deterioration of the inside of the fuel line, small particles coming off and getting under the float needle causing seepage. This really became more of a problem when B&S switched to the new style carbs. with smaller float bowl and of course smaller float with less closing force which is why I said just install an inline shutoff and use it.
Thanks for the reply Walt. I was talking about replacing the float needle and seat, sorry about the wrong terminology. I can do the fuel line also, not a big deal. Do you have any recommendations on what type to use?
I agree, you just need to replace the needle and seat. We use Simple Green as a cleaning agent in our ultrasonic cleaner, works great. Here is the procedure I recommend, do about a dozen carbs a week. Make sure you get FUEL LINE, not just rubber hose which will break down.
Needle and seat replacement
Remove the carb, and then remove the float bowl. Check the float bowl jet (which is the bowl screw) and make sure the jets both horizontal and vertical are clean and open. Tip the carb upside down and remove the float pin and float with needle attached. Look in the float needle passage and you should see the red float seat at the bottom of the passage. This is where a #5 crotchet hook would come in handy as you need to remove this seat. If you have no hook, but compressed air, you can blow through the fuel inlet and try to pop the seat out. Put your thumb over the passage to prevent the seat from flying who knows where. No air or hook try bending a stiff paper clip to dig the seat out.
I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.
With the seat out clean the passage way with carb cleaner. Now you must find a drill bit slightly smaller than the passage way, to be used to press in the new seat. Apply a very, very small amount of a very light lube to the new seat. 3-1 oil or lighter, to help seat it better. Carefully insert the new seat in the passage way with the rings on the seat down toward the carb body. Slowly and carefully force the seat down with the back end of the drill bit. Once it is seated, check to see that it did not flip and the rings are up. *Next check to make sure that the float does not have any liquid in it. *If it does, replace. *If everything looks correct, attach the new needle to the float and install with the float pin centered. It everything is correct, the float should seat level to the carb body, when looking at it upside down. If everything looks good reattach the float bowl, making sure that both the bowl gasket and the nut gasket seal properly. Reinstall on the engine and test unit. Remember to have patience and take your time. Good luck, but I don't think you'll need it.
PS: *On the side of some Tecumseh carbs you will find a plastic cover. *Under this cover will be an idle jet. *Remove it and check to see that the jet is open both horizontally and vertically. *You should be able to push the old float needle wire through the vertical opening.
