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Briggs Intek Twin Smoking

#1

C

Chapinrob

I need some ideas. I have a 2002 B&S 25hp Intek that smokes like crazy. Model 446777. Have had the problem for about 3 years. The engine had good power until one of the plugs fouls out. No hour meter, but its had a lot of use. Using SAE 30 and not overfilled. Getting oil buildup in carburetor airway. I've replaced both head gaskets, torqued to specs, adjusted valves (the exhaust valves were very crudy - cleaned and lapped intake and exhaust valves), replaced breather assembly. Engine started well and within about three minutes started pouring white smoke again. Tried Sea Foam in oil thinking maybe there's a ring stuck. Ran engine about thirty minutes and still smoking. I noticed a fine spray of oil from one valve cover but the smoke is coming from the exhaust - not just oil burning on the manifold. Also I have some oil seepage at the head/exhaust manifold union and misting around the top of the oil dip stick.

Seems like there's a high oil pressure in the crankcase. Looking for advice - I'm at my wits end. Should I go for a ring change? Maybe a broken or stuck ring?


#2

I

ILENGINE

Try doing a compression test on both cylinders, and post the results here, and if you can possibly a cylinder leakdown test if you have the tools to do it.


#3

C

Chapinrob

Checked compression today. Cylinder 1 = 125psi. Cylinder 2 = 165psi. I don't have the tools for the leak down test. Does this difference in pressures indicate a broken ring? Would this cause the blowing out of oil?


#4

R

Rivets

Did you do the compression test both wet and dry? After doing a dry test, squirt a small amount of oil in the cylinder, then repeat the compression test. If compression goes up wet, it's an indication of ring problems.


#5

C

Chapinrob

I just took out the plugs and tested the compression on each cylinder. The engine has oil - just ran it last night. Didn't try putting oil in the cylinder. Should I squirt oil into the cylinder through the plug hole for the wet test?


#6

R

Rivets

For the wet test ,yes. For each test make sure that you go through 4-5 cycles.


#7

wjjones

wjjones

Chapinrob said:
I need some ideas. I have a 2002 B&S 25hp Intek that smokes like crazy. Model 446777. Have had the problem for about 3 years. The engine had good power until one of the plugs fouls out. No hour meter, but its had a lot of use. Using SAE 30 and not overfilled. Getting oil buildup in carburetor airway. I've replaced both head gaskets, torqued to specs, adjusted valves (the exhaust valves were very crudy - cleaned and lapped intake and exhaust valves), replaced breather assembly. Engine started well and within about three minutes started pouring white smoke again. Tried Sea Foam in oil thinking maybe there's a ring stuck. Ran engine about thirty minutes and still smoking. I noticed a fine spray of oil from one valve cover but the smoke is coming from the exhaust - not just oil burning on the manifold. Also I have some oil seepage at the head/exhaust manifold union and misting around the top of the oil dip stick.

Seems like there's a high oil pressure in the crankcase. Looking for advice - I'm at my wits end. Should I go for a ring change? Maybe a broken or stuck ring?
Click to expand...



I would go ahead, and seperate the engine, and sump to see whats going on inside there. It does sound like a busted, or burnt out ring though.


#8

C

Chapinrob

Thanks WJ. I think based on my compression test, opening it up is my only option.


#9

R

Rivets

I my opinion, the compression is too high to be a ring problem. I'm leaning toward a blown head gasket. I know you just replaced them. Before you tear it down, look for an auto shop or small engine shop that has a leak down tester. Pay for the test, which will pinpoint where air is entering the crankcase. Causes could be valves, rings, head gasket.


#10

C

Chapinrob

Rivets said:
I my opinion, the compression is too high to be a ring problem. I'm leaning toward a blown head gasket. I know you just replaced them. Before you tear it down, look for an auto shop or small engine shop that has a leak down tester. Pay for the test, which will pinpoint where air is entering the crankcase. Causes could be valves, rings, head gasket.
Click to expand...

Thanks Rivets. Can you give me an idea of what a leak down test might cost? I'll call around, but not sure what a good price is in this case.


#11

R

Rivets

I do them for $10-20, depending on the engine.


#12

lawn mower fanatic

lawn mower fanatic

I moved your thread to the Small Engine & Mower Repair Forum. :smile:


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