Briggs & Stratton 6.5 Intek

[ron411]

Hi all, I have a B&S 120312 0143 E1 engine that won't start. It is from a pressure washer and while I was using it it started to loose power and sounded like it was running out of gas. I have done a lot to troubleshoot it but I am quite confused with what is going on. Here is what I have done and at a loss as to what to do.

Verified spark.
Cleaned Carb.
Adjusted valves. both intake and exhaust needed adjustment.
Engine started and ran for about 3 min the same symptom. Sounded like it was running out of gas and quit. Have not been able to get it started since.
I also noticed while it was running and now when I pull the rope that gas is coming out of the hole that is on the Air Cleaner side of the mounting flange.
Took the carb off and cleaned it with carb cleaner and wire through all the ports.

Performed Leakdown test all is good but no compression with compression test.
Took the valves out and the cylinder head off. Everything look great. Valves look good, gasket look good, Top of piston looks proper, cylinder look good. Put it all back together. Did another leakdown test with valve cover off. Showed moderate loss. Way up in the green with valve cover on but still no compression with compression test.
I am at a loss between no compression and gas coming out the hole what to do next. Thanks for any thoughts, advice....\
Ron

 

[Rivets]

You say that the leak down test idicates no leaks, but you get no compression? This does not make sense. When you did the leak down test, do you hear air escaping through the muffler, carb, dipstick tube or anywhere else? Are you sure that the piston was at TDC and did not move? How much pressure are you using when preforming the leak down test, less than 100 psi will give inaccurate readings. I have found that doing the leak down test, is more accurate than a compression test.

 

[ron411]

Rivets, Thanks for the reply, I agree it does not make sense. I am using the HF leakdown tester. I did the two tests back to back. One thing I did not mention is that when I put some gas into the cylinder from the spark plug hole it does not start. I am not sure total pressure on the leakdown because I just adjust it to the 0 reading. I did leave the pressure on for about 5 minutes and the pressure was holding.

 

[Rivets]

I don't think you are using the leak down tester correctly. It is very difficult for me to explain how I do the tests, but maybe these sites will help you.

How do I use this leak down tester?

U-tube video

http://www.google.com/url?sa=t&rct=...0ou2aibBElXpsbowflsHkGw&bvm=bv.69620078,d.aWw

 

[ron411]

I don't think you are using the leak down tester correctly. It is very difficult for me to explain how I do the tests, but maybe these sites will help you.

How do I use this leak down tester?

U-tube video

http://www.google.com/url?sa=t&rct=...0ou2aibBElXpsbowflsHkGw&bvm=bv.69620078,d.aWw

Thanks for the links. I think what I am doing is correct. However the one thing I now understand is that the pressure on the AC is important to be set high. Mine is at 100 lbs so when I said I did not know how much pressure "I just turned the regulator on the LDT to 0" I thought that was all that mattered. Since I have gas coming out the vent port I and do not know if I have two separate problem or there just is no gas getting to the cylinder. I ordered the carb rebuild kit and a new float figured that was a cheap way to at least hopefully get somewhere. There was a thread on another forum that I read the other day where someone has similar problem with the LDT vs compression test and what was suggested was the the cylindrical was for some reason larger at the bottom than the top. At TDC things were good but when the piston traveled to the bottom it leaked. He said he measured top and bottom with telescoping gauge and sure enough there was a problem. My engine feels like it has good compression when you pull start it. I used my compression tester on another engine I have and it is fine.

 

[Rivets]

A cylinder is tapered and as you said larger at the bottom than the top. When doing a leak down test, the piston should be blocked or help at TDC on the compression stroke through out the test. As air pressure is applied the piston will want to travel downward and if allowed to do so will not give accurate readings. Looking at the gage readings will tell you the present of leakage, but not where. While the air is applied, you should also listen for where the air is escaping. Through the muffler, bad exhaust valve. Through the carb, bad intake valve. Into the crankcase, bad rings.