Small Engines (Lawn Mowers, etc.): Small Enfine Starting Problem, briggs stratton engine, front tine tiller

Question
QUESTION: 
I have had a Rally Front Tine Tiller for several years. It is Model No. FY850B 5 HP 24 Inch.
I use it once or twice a year to till a 20'x30' garden area, mostly as a pleasurable past time.

The Rally uses a Briggs & Stratton Engine, Model 135202, Type 0119 01, code 9311225.
It has always started quickly without any major problem. This year, it just will not keep running.
The Spark plug is clean and getting a spark. By putting gas in the plug cavity or using Quick
Start, I can start it, but it will not keep running. There appears to be no gas flowing to the
Carburetor, as evidenced by the fact that, after any of the sessions, the spark plug show no signs
of dampness.

The Manual, between several suggestions, mentions to take the Gas Tank out and clean any
obstructions. The problem is that the option is not as easy to carry out as it sounds. I have no
detailed schematic for carrying that task or any other suggested method to promote gas flow to
the Carburetor. It stresses to check the oil level and to change it with some degree of frequency. I
have not changed it, but appears clean and it is at a proper level. It also mentions care for
cylinders and suggests pouring an once of oil through the spark plug hole and pull the starter
handle several times to distribute oil. However, it does not indicate what oil is to be used, unless
is the oil SAE 30.
Can anyone comment on this?
A repair shop is my last recourse, if truly necessary. Given the current problem and the rare use of
the Tiller, I have been wondering if it is worth incurring the possible repair cost.

I would greatly appreciate any suggestions.
Thank you!
ANSWER: Bernie
Since this carb is tank mounted and the fuel pick up is in the tank you will need to remove the carb from the engine as well as the tank. You will see a pick up tube on the bottom is a screen this may be clogged. I would change the oil especially for a tiller as they drive up a lot of dust and some may get ingested in the engine and in the oil even thou it looks clean it may be contaminated. You can use marvel mystery oil in the cylinders or SAE 30 only when you are going to store it, It will smoke blue smoke when ever you go to start it back up.

Thanks

---------- FOLLOW-UP ----------

QUESTION:  Thank you, Ben, for your quick response!
I gather that you are familiar with the actual
engine/carburetor setup of that model. Parts are tightly put together and I still can't see where the gas leaves the tank and its travel route to the carburetor.
How is the gas pulled out of the tank?
There is a cloth/screen inside the tank that appears to be attached to some port inside.  I can't tell if the port is at the bottom or the top of the tank.
There is a compartment attached to the topside of the tank with a removable side-cover. I removed it and there were some traces of gas in a small cavity within the uncovered chamber. Do you have any suggestions as to where/how I could obtain a detailed diagram of that exact unit?  
Thanks, again!

Answer
Bernie
The carb itself has a small tube from the main pick up tube I would like to send a picture of one of the type carb that is on that model,so you can see. If you take off the bolts to the intake and a few springs the whole carb/tank will come off.

E-mail me and I will send you the diagram
gb@gbelect.com

Thanks