Farmall Cub Leak Down Test.

R

RunningRed

Well-known member
Ok I got my leak down tester today and ran the test after leaving the cub warm up.
#1- 7% loss
#2- 5% loss
#3- 8% loss
#4- 6% loss
Also when I checked the compression numbers on all cylinders they are as follows.
#1- 96psi
#2- 95psi
#3- 100psi
#4- 99psi
So it appears my engine is in very good condition. Nothing that appears to contribute to the low and mid idle popping noise out the exhaust. I went through the entire ignition system, cleaned and double checked everything, including removing the distributor and taking it apart for a cleaning. Setup the static timing at idle and verified timing at high idle also. I did notice at mid idle it's pops enough that it tries to shut off after about 15-20 seconds. I pulled the choke out some and it seems to help some. At low idle it still pops as usal. I went through the carb yesterday and reset the float and cleaned everything especially the low idle tube and set idle screw but it seems to not have helped. At high idle it runs great. I also went back through and checked all the valve lash again and all is good there, set at .015. The hard starting has quit, so either it was something in the carb or the MMO I put in the fuel has helped in some way. This appears to be a gremlin that I can not find.
 
good #s on the engine so it has to be fuel or ignition, while its running spray some carb clean around the manifold to block to make sure you do not have a leaking manifold gasket, it will rev up if it has a leak
do you have a IH or Zenith carb ?
 
tst said:
good #s on the engine so it has to be fuel or ignition, while its running spray some carb clean around the manifold to block to make sure you do not have a leaking manifold gasket, it will rev up if it has a leak
do you have a IH or Zenith carb ?
Click to expand...
It's a IH Chinese aftermarket carburetor, I have the original IH carburetor too but it did the same thing.
 
You must log in or register to reply here.
Back
Top