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Discussion Starter #1
It's a Briggs & Stratton, 12.5 HP IC, #286707, Type #0441-01 (electric start). The only way it start cold is if I pull the air cleaner (starts right up no problem when I do that).

I already replaced the air cleaner and fuel filter when the problems began to no avail.

Any thoughts?
 

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Chances are you have lost intake valve clearance, and the engine is trying to run on the charge it just burned, some of which escaped through the intake valve and filled the carb. and air filter. By removing the air filter, you are dissipating the burned charge in fresh air, which the engine can run on. Add a teaspoon or so of oil to the cylinder to seal the intake valve. If the engine starts OK, that's the problem. This trick will only work for one start. Once the engine warms up, the aluminum block expands more than the steel intake valve, giving you some clearance. The ultimate repair is to check and adjust the valve clearance, they verify that your air filter is properly sealed, as dust ingestion will cause this problem.
 

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Discussion Starter #4
Any chance the air filter is interfering with the choke?
Nope.

Chances are you have lost intake valve clearance, and the engine is trying to run on the charge it just burned, some of which escaped through the intake valve and filled the carb. and air filter. By removing the air filter, you are dissipating the burned charge in fresh air, which the engine can run on. Add a teaspoon or so of oil to the cylinder to seal the intake valve. If the engine starts OK, that's the problem. This trick will only work for one start. Once the engine warms up, the aluminum block expands more than the steel intake valve, giving you some clearance. The ultimate repair is to check and adjust the valve clearance, they verify that your air filter is properly sealed, as dust ingestion will cause this problem.
Thanks. I'll give it a try. The old filter was pretty dirty so I'm hoping it's just dust injestion. You really know your stuff!
 
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