# Honda GC160



## RKDOC (Jun 20, 2006)

On this engine I can not get fuel to pump to the carburetor. I have good fuel flow in the line hooking to the pump from the tank. The line to the block is good, and not leaking. When i pull the engine over just a bubble will appear at the hose going to the carb. I replaced the pump and still does the same thing. The engine is not very old and I have done a leakdown test with no leakage. What would cause there to be no vacume/pressure from the engine to operate the pump? What can I check to find what is wrong? Thanks for any help or advise.

P.S. i have checked for kinked lines and can find none.


----------



## paulr44 (Oct 14, 2008)

I'm assuming there is a fuel pump between the tank and the carb. The breather system is responsible for maintaining a partial vacuum in the eng. crankcase when the eng. is running. If it isn't working properly, it will allow air to escape, and air to enter the crankcase freely, and that would prevent a crankcase based impulse fuel pump from working at all. If there's a CC leak such as an ill-fitting dipstick tube, a dipstick missing the o-ring, blown crank seal etc. the result would be the same.


----------



## RKDOC (Jun 20, 2006)

Thanks for the reply Paul. If I remove the breather, is there any way to tell if it is working properly? Thanks for the help.


----------



## paulr44 (Oct 14, 2008)

Well, to test a breather you actually need it in place. To test it, you would do a crankcase vacuum test using a manometer (water column). You can make one at home using about a 12' length of clear tubing with an I.D. of about 1/4" or 3/8", a board to mount it to, a magic marker to make ruler 1" inch increment marks. a line clamp and water.

You may need a rubber cone-shaped stopper that you can route the hose through to plug into the dipstick tube, or other high-level port on the engine. YOU CAN'T use the oil fill plug boss as you can't work that low in the block.

The one I made for work uses a hose that just happens TO FIT NICELY into most dipstick tubes with a tolerance fit creating a good seal.

Open this PDF, go to PDF page 11, and bottom of pg. 13 and top of pg. 14.
http://www.kohlerengines.com/onlinecatalog/pdf/tp_2043_a.pdf

If you google it you'll find a lot of examples.

http://www.thefreedictionary.com/manometer
http://www.thefreedictionary.com/_/viewer.aspx?path=hm&name=A4manome

KEY INFORMATION:
Coloring the water is optional - I grab bottled water and discard it when done.
YOU MUST have the connection to the engine BLOCKED OFF whilst starting the engine.
DON'T FILL the tube up all the way with water - only about 12" to 18" from the bottom loop is necessary.
The engine should be a bit warmed up, not stone cold.
Connect the manometer, start the engine, run it up to speed and release the clamp/open the valve on the hose, then READ the difference between the columns. Or, you can read from zero on one side and double the reading.

You MUST have a vacuum reading, meaning the water in the leg of the loop closest to the engine MUST rise, not push down. How much vacuum varies by eng. etc. but you should expect to see at least 8" to 10", Honda doesn't publish specs., How well the breather seals as designed and other factors would be the basis for benchmark, so *I can only speculate* on the GC160 value.

Obviously, if the water pushes down (CC pressure), then there's a breather or other problem. Head gasket leaking pressure into crankcase, valve cover gasket not sealed, combustion blow-by etc.


----------



## Don L (Jul 14, 2012)

Had never thought about lack of engine pulse keeping an engine from running,thanks for providing that info.
I assume you would have to hook up a gravity flow fuel system to run this test.
I have'nt had much experience with these engines,guess they are too reliable, I'm always glad to learn more.Thanks


----------



## paulr44 (Oct 14, 2008)

We've seen oil having been overfilled on certain twin horizontal engines, foaming and the foam blocks up the impulse hose and shuts down the engine (as the fuel pump stops working). You have to keep it simple whenever possible, as the basics are just that and go from there.


----------



## paulr44 (Oct 14, 2008)

P.S. Old tecumseh engines would sometimes push oil out the breather when the dipstick tube was loose. Common on old snowblowers...I made a habit out of tightening every tecumseh dipstick tube that was threaded in. On some snowblowers, even had to put a gasket under the tube flange to help it seal to seal up the crankcase so the breather could do it's job.


----------



## RKDOC (Jun 20, 2006)

Engine has vacuum. Because of the leaf cutter bees plugging the vent port, No suction to the pump. Thanks for the help.


----------

