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Rick
Rick, Small Engine Technician
Category: Small Engine
Satisfied Customers: 3844
Experience:  Outdoor Power Equipment technical trainer since 1990, covering eight states.
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Hi I have just rebuilt an Intec I/C 260 ,I have matched

Customer Question

Hi

I have just rebuilt an Intec I/C 260 ,I have matched timing marks ensured thst ther is a key in the flywheel shaft end etc but when I try to start it I get blowback through the carburetor. What could be causing this?
Submitted: 4 years ago.
Category: Small Engine
Expert:  Curtis B. replied 4 years ago.
For engine to blow back through the carburetor, it has to be out of time or a valve has to be open. If you have the internal two marks together, and the flywheel key in place, the problem would have to be a valve open. Double check for clearance on the valves. If you have clearance, you have a leaking valve. The valve will need to be checked, can be bent, sticking, or not seating on the surfaces. What model is this? Overhead valves? Or old flat head? With overhead , the head can be removed and liquid checked by pouring water into the ports, one at a time, to see if the valve is leaking. WIth flat head, not so easy. Valve has to be removed and the valve seat lapped. Let me know. Thank you.
Customer: replied 4 years ago.


Hi Curtis


 


Thanks for your response. I fitted a new cylinder head so had ruled out valve seating problems but checked it anyway. On rotating the crank slowley I notice that the exhaust valve lifts very slightly on the compression stroke, this is caused by a small metal shape mountred on the camshaft between the gear and fist cam lobe. could this be the cause or is it part of th easy start mechanism?


 


Richard

Expert:  Curtis B. replied 4 years ago.
That is the compression release working. Part of the easy start system.