71 doesn't get fuel

jet1959mo · #1 10-25-2012, 10:18 PM

I am confused. The 71 Cub, Kohler K161S we tried to start today isn't feeding fuel into the carb. Cleaned the glass filter and put new screen, gasket and hose. I don't see a fuel pump on the engine or where one would go.

Methos · #2 10-25-2012, 10:53 PM

The sediment bowl has a filter on it that can get plugged up. Might be junk in the lines or jets on the carb itself. Time to clean the carb and replace the fuel line.

TSWolf · #3 10-25-2012, 11:03 PM

Check the tank to see if it is rusted or has debris in it, that could be plugging up the hole in the bottom of the tank. It can not be anything in the carb that would cause gas to not get to the carb itself.

jet1959mo · #4 10-25-2012, 11:10 PM

Quote:

Originally Posted by Methos

The sediment bowl has a filter on it that can get plugged up. Might be junk in the lines or jets on the carb itself. Time to clean the carb and replace the fuel line.

Sediment bowl (I call glass filter) has been cleaned and parts replaced, new fuel lines. Tank is clean. We get fuel to the carb, just not being pulled into the carb.
I have one other option, rebuild carb.
So I take it this engine has no fuel pump. Just gravity feed? I'll try to get a better pic of the carb area and post it here.

ihcc104 · #5 10-25-2012, 11:37 PM

Well if you have done all of that, make sure that you have the stock cap on the gas tank, If the air hole/breather is plugged in the top of the cap or it is non-existant (aftermarket) and no air can get through, then no gas will come out because it will have back pressure.... Just a suggestion.

lwrehm · #6 10-26-2012, 05:48 AM

JET...you are correct that engine does NOT have a fuel pump. Its all gravity.

ol'George · #7 10-26-2012, 07:03 AM

Sometimes the needle valve will stick closed, I have a engine that does that.
I just tap gently on the carb bowl with the handle end of a screwdriver.
Were not talking a big hammer here, just a light tapping.
If that brings no joy, take the carb apart and clean it.
If your lucky you might get by without damaging the gaskets.
I always try the simple things first.

JayJay · #8 10-26-2012, 07:47 AM

I'm with Old George on this one. The needle valve sticking is a common problem on engines which have been sitting for a while. If the tapping doesn't get it, remove the bowl and make sure the needle is dropping down from the seat; re-assemble and test. If the motor runs you can order a new gasket.

I would also recommend getting a new float, whether or not you rebuild the carburetor. I discovered that Kohler's original float design had a flaw in it that resulted in a broken "down stop" which, in turn, allows the float to descend to the bottom of the bowl resulting in an "over extension" of its link to the needle valve. The float would get hung up in the down position which caused gas to flow ALL the time. Kohler (or Carter) redesigned the float so that the part doesn't break.

Adjust the float per the manual instructions.

ronalddipietro · #9 10-26-2012, 07:53 AM

will it fire or start if you skeet gas in carb?

jet1959mo · #10 10-26-2012, 08:21 AM

Quote:

Originally Posted by JayJay

I'm with Old George on this one. The needle valve sticking is a common problem on engines which have been sitting for a while. If the tapping doesn't get it, remove the bowl and make sure the needle is dropping down from the seat; re-assemble and test. If the motor runs you can order a new gasket.

I would also recommend getting a new float, whether or not you rebuild the carburetor. I discovered that Kohler's original float design had a flaw in it that resulted in a broken "down stop" which, in turn, allows the float to descend to the bottom of the bowl resulting in an "over extension" of its link to the needle valve. The float would get hung up in the down position which caused gas to flow ALL the time. Kohler (or Carter) redesigned the float so that the part doesn't break.

Adjust the float per the manual instructions.

The cap is the original (The whole tractor is original parts), it isn't plugged as fuel is getting past the sediment bowl. As far as fuel flow in the carb, I know what we done wrong now. We replaced the fuel line from the sediment bowl to the carb with one of the same length that came off (not knowing this engine didn't have a fuel pump and was gravity fed) no wonder the owner couldn't get it to run. Well, it was the wrong length to begin with resulting in no down flow, duh. I viewed many photo's till I found one that shows the left side of the engine up close to see that the fuel line is very short and straight. We will fix it and test then purchase a carb rebiuld kit and float to go on later. We do know it will run because we shot a tiny bit of starter fluid in it and it tried to fire. Once this is all done and it does try to run, then we will go through it and do all the maint. it needs.
Thank you all for your help.