Briggs 17.5 Intek OHV engine and push rods

J

JDDK

Forum Newbie
My secondary mower (only because of this problem) is a Husqvarna ZTR. It is powered by a 17.5 HP Briggs - Stratton Intek OHV engine. It has a tendency to break push rods. Is this a problem inherent with this engine? Is there something I can do to help prevent this? It's getting a little old replacing push rods towards the end of each mowing season! Oil is kept clean and filter changed. Thanks for any comments.
 
I can think of several possibilities here. The Intek has a plate that the push rods pass through, and if the plastic protector is damaged can wear the push rods, especially the intake, aluminum. The other thing that I can think of is if there has been a mouse nest or other debris on top of head, under the blower housing, can cause the head to overheat, which loosens the valve guides. The guides always seem to migrage out, and the rocker arm will hit the guide, either bending or breaking the push rods. If this is the case, you will need to replace the head, because even though you can tap the guides back in place, they won't stay in place.
 
I have found another possible cause. When the push rods are replaced it is important the the rock arm nuts are torqued properly. If they come loose the push rod will jump causing breakage. Found this out when a customer replaced his own and did not follow the proper procedure and torque, just snugged them tight.
 
Rivets said:
I have found another possible cause. When the push rods are replaced it is important the the rock arm nuts are torqued properly. If they come loose the push rod will jump causing breakage. Found this out when a customer replaced his own and did not follow the proper procedure and torque, just snugged them tight.
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Yep is it .04 on the intake, and .06 on the exhaust, or the other way around? I know one needs the extra .02 for some reason I just cant remember which one.
 
Most Briggs OHV engines have a valve clearance of .004-.006 for both valves and a torque of 70 inch pounds.
 
Depends on what model ohv.
Model 21 is .004-.006.
Model 28 and 31 is .003-.005 intake and .005-.007 exhaust.
If the intake is not set right then the decomp wont push valve down far enough for easy starting.
 
Seeing he didn't post which model he has, I just had to assume that he doesn't know the difference between a 21, 28, or 31 and gave him clearances that will cover all. Better than the .04 and .06 that was posted earlier.
 
Sorry rivets but was meant for op and not you regarding clearances.
Think we posted at about the same time.
I thought id give the op the info just in case.
 
Many thanks to all who replied. More than enough info to head me in the right direction. I do have a model 21 so the clearances given for this model was great. Thanks again everyone!
 
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