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Small Engines (Lawn Mowers, etc.)/17.5 HS BS can't start anymore


QUESTION: Few years ago I bought riding mower Troy Bild 13AD609G063 with Briggs Stratton 311777 type 148-E1 engine 17.5 HP Ė
It had minor issues (or so I thought) but it would start easy and run.
After a short time, it would start emitting white smoke and eventually would foul the pug with oil and oil would gush through the breather to the carb and kill it.
Compression check reviled good valves, and leak through the piston rings so I bought a set and took the engine apart to replace them.

I assembled the engine, put a new carb spark plug etc and now, engine wouldnít start! It would crank but no start.
Iíve tried repeatedly to adjust the valve timing (as per manual) and Iím sure I know which is intake (lower) and exhaust valve (upper) also, exhaust lifter (rod) is steel as opposed to Al for intake.
However, I might be wrong there as I read somehwere that some engines have intake Vale on top...
Am I correct?

I am sure, when assembling the engine; I aligned the mark on gears (camshaft had a hole, IIRC). Cranking the engine, I get the spark on the spark plug. I believe carb provides the fuel too.
I am at loss and have no idea what to do and what should I look at. Iím at point of just dumping it or, again taking the engine apart for one final look.
Could you please help?
Thank you

ANSWER: The intake valve is on the carburetor...I believe it is the top valve...hard to see in the drawing.

The exhaust valve is on the muffler side of the head.

What did you set the valve clearances at?  Intake?  Exhaust?

Did you download the engine service manual?  All you have to do is Google "Briggs and Stratton OHV manual"...use Google, NOT Bing.


---------- FOLLOW-UP ----------

Yes, I have a PDF of this manual. Thanks.

I adjusted valves as per spec, .004Ē (intake) and .006Ē exhaust valve.
Looking at valve yesterday,  I am sure Top Valve is Exhaust (adjacent to manifold) and bottom is intake as the I can trace intake manifold path to it.
Iíve tried lifters on both locations, though but now replaced them back, correctly.

I am not sure what to do next. Iíll have to check a carb again as it is not set- I needed to start the engine first. I might try carb cleaner fluid into the cylinder first to eliminate that as I think Iíve tried that with lifters reversed .
Running out of ideas but I must overlooked something simple
Thank you

ANSWER: Instead of carb cleaner you can use a primer bottle and gas.  I use a plastic bottle with a tapered tip, like the old style diner ketchup bottles.  Bought the bottle at Wal-Mart in the cooking section for about a dollar.

Even with the carburetor off, you should be able to prime the engine via the intake manifold and get the engine to at least try to start.  This way you know the compression, ignition and mechanical timing are correct, and you have spark...this only leaves fuel as the issue.

If the engine will not even pop by priming then you may not have compression, the mechanical timing (cam/crank) is not correct, or the ignition timing (flywheel key) could be the problem.

Let me me know if the engine tries to start when priming.


---------- FOLLOW-UP ----------

I finally tried again, with raw fuel into the intake (manifold/carb was removed).
It wouldn't start at all!
I must sat that on occasion, it would POP or so like it did with carb installed and fuel connected.
There is definitely compression and I've also checked it with the compression gauge tool.

So,, as you said issue might be spark timing or cam to crank (which I am almost sure I've done well).
I am not sure what controls the spark timing? Just the flywheel with the key?
I should fine dime to look at that this weekend, I hope.
What do you suggest next?
I would like to avoid taking engine apart again but if that's what it takes...
Thank you

Spark timing is controlled by the flywheel key...not much you can do...just make sure the key is not sheared.

To assist with cam/crank timing you an check for valve overlap.  The valve overlap will provide an indication of the mechanical timing.


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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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