on DYT 4000

[Leo Rabon]

Inherited Craftsman DYT 4000. 18.5 HP B&S. The tractor is garaged and every morning I smell a strong order of gasoline in the garage. I have replaced the fuel lines (every piece) and put on a new fuel pump. I find no leaks anywhere in the fuel system. The carb is not leaking. Is it possible that there is a problem with the gas cap vent ???

I need to correct this problem ASAP. Any advice or help will be appreciated.

Thanks
Leo

 

[Baby Grand]

Just a suspicion: the fuel solenoid (on the bottom of the carburetor) may have failed, allowing fuel to gravity drain into the carb. From there it can flood the air filter, giving your garage that odor. It can also flood into the cylinder, run past the rings and into the crank case, diluting your oil. As you can immagine, this is not a good thing.

Check your air filter for raw fuel before you start it next time. Also, take out the dip stick, note the fluid level and give it a sniff. Your oil level should not be much higher than when you last shut it down. That should help identify if this is happening.

I had this problem on our 21hp DYT and "solved" it by installing a plastic on/off twist valve in the fuel line, between the tank & the carb. New solenoid valve was around $40, the plastic valve was around $5.

 

[Leo Rabon]

Baby Grand:
Thanks for your reply. It does make sense. I do wonder how the gas could get into the air filter since the air filter is above the tank and carb. I will check the oil and see if there is any contanimation of gas. When I changed all of the gas lines I did install a plastic cutoff in the gas line just to have it but I did not cut the gas off there when parked. Question: When I park the tractor after I have finished using, should I shut the gas off and let the motor run until all of the gas has been burned out of the line (from the fuel cutoff) or just park it and cut the gas off??????
I inherited the tractor with about 100 hrs on it, a 2004 model. When I got the tractor, I did unscrew the bowl on the bottom of the carb and whew!!!! what a smell of rotton gas. I drained the bowl and cleared the lines of old gas and replaced with new fuel in the tank. I did check to see if the fuel solenoid worked and did hear the "click" of the solenoid so I thought it was working although it may not be seating properly when it is shut down. I really thought I would have to have the carb cleaned and rebuilt but to my surprise, after the valves were adjusted on the motor, it started and ran fine. It probably does have some build up on the needle and seats but again the motor runs fine.
Thanks again for your help.
Leo

 

[Baby Grand]

You know, you're probably right about the air filter not flooding since it's uphill from the carb. Now that I think about it, I seem to remember that when it happened to me, I went to start the engine after it had sat for a week, the gas that was filling the cylinder shot out the muffler.

If you use the shut off valve, I don't think you need to run it dry every time you shut down - just if you're putting it away for the season. I avoid running too lean a mixture very often - I seem to remember that it's not good for the engine for some reason. Maybe someone can confirm or deny this superstition of mine.

 

[Leo Rabon]

Thanks again for your response. If the solenoid is the problem (gas in the oil), I will probably go ahead and get the carb rebuilt so I can move on with it working properly. It is most likely the problem as you mentioned. The carb had really bad!!! gas in it for a while. The gas had 10% ethanol in it. Fortunately, I can still get 93 octane 100% gas and that is what I use. It cost a little more but for what I use, the difference in price would take years to pay for the price of a carb rebuild.

Many Thanks
Leo

 

[RandyT]

Guys, take it from a Briggs and Stratton service center and Briggs and Stratton Master Service Technician the solenoid has absolutely nothing to do with filling of the carb or causing fuel to leak into the engine. The only purpose of the solenoid is to attempt to prevent the engine from banging after shutoff what we call afterfire. It you are going fuel into the oil it is a carb needle valve problem or a leaking float (fuel inside float making it sink) about 99 percent of the time.

The fuel flows through the needle valve and it shut off by the float rising to close the valve. If the valve is not sealing the fuel will continue to fill the fuel bowl and flow through the bowl air vent into the intake manifold, past the intake valve into the cylinder and then past the rings. It will also flow into the breather hose into the breather and into the crankcase if it is attached toward the bottom of the air intake below the air filter.

If you would remove the plunger in the solenoid the engine would continue to run normally and will not leak fuel into the engine if the carb is working properly, ie needle valve.

 

[Baby Grand]

Thanks, Randy - I never really understood what that solenoid valve did, so I guess I just found it shiftless and suspicious. How wrong I was. Needle valve makes sense to me.

 

[Leo Rabon]

Randy:
Thanks so much for your reply. What little I know about these things makes me "dangerous". I have learned so much from this forum thanks to great people like you and the many others that like to help people. Like Baby Grand, I now understand what the solenoid does and appreciate your help so much. I will trailer the mower to a real technician this Saturday and get it fixed. I will let everyone know what takes place.

Thanks Again
Leo