QuestionQUESTION: I have an 18 hp v-twin model 350447 Type 1206. The info I can find on the internet says .004"-.006" valve lash for both intake and exhaust. I have been told that this is actully too tight and should be more like .010"-.012" especially on the exhaust valve. What would you reccomend? Also should this be checked cold or hot?
ANSWER: Hello Mark:
I have Found that the Clearances that the OEMs Suggest Actually Cause some Problems with the Internal Compression Release. I have Experimented with the Settings and Now Use the Following Setting for the Valves. The Intake .003in - .005in and the Exhaust .008in - .010in. The Engine has a Compression Release and this Release Seem to Function Better at these Settings. Always Check the Clearance when the Engine is Cold. Hope this Helps. I am Here if You Require More Assistance. Let Me Know What Happens, Please. Thanks.
Good Luck
Respectfully
John
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QUESTION: Thanks for the quick response... Now for the next question. On the Carburetor near the top there is a hose barb that looks like a vacuum line would hook to it. On my mower, there is no hose going to it. Is this right, or should I plug it up?
ANSWER: Hello Again Mark:
The Port you are Asking About should have a Hose to One of the Valve Covers. You can View a Breakdown/IPL of the Engine at this Site Addy, http://www.outdoordistributors.com/ and Select the B. Then Select Briggs and Stratton. Then Select Don't have Part Numbers. Then Select the File #35. Then Select the Folder #350400. The Breather Hoses are Breakdown/IPL #s 11, 11A and 11B on Page 2 of 36. If your Does Not Use a Hose, then Block the Port Off. It will Draw Grit into the Intake Bypassing the Air Filter. Hope this Helps. I am Here if You Require More Assistance. Let Me Know What Happens, Please. Thanks.
Good Luck
Respectfully
John
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QUESTION: The orignal problem I had started three weeks ago. The push rod fell out on the exhaust valve on one of the cylinders. I put it back in (after checking to make sure it is not bent) and adjusted the valves to .006" as the book calls for. The next week the exhaust valve seat fell out of the head. So I took it appart and put it back in. In the process I find that the fins on head are packed full of gunk. I cleaned them out thinking the poor cooling may have caused my problems. Now this week... I mowed for a couple hours and then when I shut down the engine backfired and the push rod fell out again. What can be causing the push rod to pop out?
PS.. The engine has always been hard to start. The valve settings you reccomened seem to have made it start better.
As for the carb hose fitting. I tried to plug it but then it ran very poorly (sputtering with heavy black smoke) so I left it open like it was before.
AnswerHello Again Mark:
If the Problem is Persistent, then Use Red (High Temperature) Thread Lock on the Valve Adjustment Lock. This is Starting to be a Problem with All the OHV Engines. I have Done More Valve Resetting in the Last 3 Years than I had to Do in the Previous 25 Years. I had to Experiment to Get the Right Valve Settings. The .006in on the Exhaust is Just Too Little and .0012in is Too Much. But I Finally Found a Setting that Works Well. Hope this Helps. I am Here if You Require More Assistance. Let Me Know What Happens, Please. Thanks.
Good Luck
Respectfully
John
