# Possible stuck valve on Briggd 11Hp v.shaft



## treeboy (Jun 14, 2008)

I am new to this group so I hope I'm doing this right! I recently replaced the engine, 11Hp Briggs IC. It was a used engine and it won't start. I discovered that there are no points after removing the flywheel. Anyway I now have a seemingly weak spark, but still a spark. When I pour a bit of gas into the carb to prime, it seems to exhaust back through the carb a bit. No firing or poping. After reading around, I suspect a stuck valve? Anyone know an easy way to unstick or check this. I guess I will have to pull the head, but then how to unstick? Thanks


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## treeboy (Jun 14, 2008)

*Valves are moving O.K.*

I pulled the valve spring cover and determined that the valves appear to be moving correctly I guess. 

Now I am going to try to clean the carb. I ran out of cleaner so I am going to get more and also a can of starter fluid. I still think it should fire or at least pop a little after pouring some gas in the carb but it doesn't. Still not convinced of a strong enough spark. It has a new plug. I bought a new coil/magneto today, but havn't put it on yet because I'm not convinced the old one is bad? Any ideas ?
Al


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## 30yearTech (Sep 14, 2006)

You may want to check the valve lash, if you have a stuck or sticking valve, it may not be closing all the way. Excessive valve lash would indicate this, and then you could proceed with removing the head to inspect. It could also have a problem with a loose valve seat, as you should get some kind of "Pop" with a prime, if you have ignition spark.


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## treeboy (Jun 14, 2008)

In a nutshell, what is valve lash and what holds the valve seat in place and what is the fix. Can I re-seat the existing seat or does it have to be replaced? Thanks.
Al


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## 30yearTech (Sep 14, 2006)

treeboy said:


> In a nutshell, what is valve lash and what holds the valve seat in place and what is the fix. Can I re-seat the existing seat or does it have to be replaced? Thanks.
> Al


Valve lash is the clearance between the lifter and valve stem Intake .005" - .007" and exhaust .009" - .011" should be the clearance for your engine.

Sometimes you can reinstall the old valve seat, if thats the problem post back.


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## treeboy (Jun 14, 2008)

I finished soaking & cleaning the carb, it was a rusty mess inside but clean now. Put it back together & tried again with ether (starting fluid) to start. Not a single pop. Still has a weak spark. I'm thinking the weak spark could be because of slow-w-w cranking. I have another starter that i will pull apart tomorrow (Monday evening) and check the brushes, lube the bearings, & make sure there are no burnt windings or intermittant solder connections on the armature. It has a broken plastic positive battery lug so I may consider epoxy or something. The other starter, the one now in use I think has been somewhat trashed due to tooo long of crank-offs. But aside from the slow/starter thing, there is some compression (not sure how much exactly) but still seems to exhaust a bit through carb. Both valves seemed to move freely. I think that there was more than .010 clearance at valve stem end. As memory serves me, maybe as much as .100 on the intake, bur not certain. I will pull hood and head tomorrow night. I made a valve spring compressor from a piece of spring steel that worked o.k. I didn't see any place to adjust the valve action though? Thanks again for all your help.
Al


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## phillipmc (Jan 27, 2008)

Yes i would check your valve clearance. As that could have a big role in timing. I would also check your flywheel key. If its sheered it could also throw your timing off.


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## treeboy (Jun 14, 2008)

Its a brand new key. The engine hasn't even popped since the key was installed. Flywheel is torqued down very well. Thanks for your input!
Al


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## COMP (Jun 11, 2008)

treeboy said:


> Its a brand new key. The engine hasn't even popped since the key was installed. Flywheel is torqued down very well. Thanks for your input!
> Al


 does it have any compression ?


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## treeboy (Jun 14, 2008)

I checked the valve clearances when closed. The exhaust has .010 and the intake has .004 exactly. Just as an example, if the head bolts should be torqued to 50 lbs they were probably about 15 or 20 lbs, not finger tite but definitely not quite enough. As I mensioned earlier it seemed that there was some back pressure coming back through the carb while cranking. Not popping, just some light vapor coming out. It seemed to me more than would be normal. At a visual glance the cylinder walls seemed smooth & o.k. to the naked untrained eye. The valve seats appeared normal to the naked eye. This is an old mower and I hope to get the rest of the year out of it. Do I need to pull the valves and do a quick manual valve grind with compound or take a few thou off the end of the intake valve stem ?? Or just put it back together and torque the head bolts and try again. I need an expert opinion ! Thanks Guys!
Al


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## phillipmc (Jan 27, 2008)

50 ft lbs of tourqe on the head bolts is to much the most iv seen is 220 in lbs . If you will provide a model type and serial i will look up the tourqe spec for you. Also you may want to check your clearance between the flywheel and the coil pack. It should be between .008 and .012 ( use a old buisness card. ) Electronic Ignition either works or it doesn't unless its dieing when the engine gets hot. Have you actually checked your compression with a tester ? As a good rule of thumb your compression should be no less then 50 psi but i like to see no less then 60 psi


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## 30yearTech (Sep 14, 2006)

treeboy said:


> I checked the valve clearances when closed. The exhaust has .010 and the intake has .004 exactly. Just as an example, if the head bolts should be torqued to 50 lbs they were probably about 15 or 20 lbs, not finger tite but definitely not quite enough.


I would remove the intake and take a little off to bring it into spec. .004" is not enough and can disappear when the engine gets hot. While you have the valve out I would lap it in just for good measure. I believe the head bolts should be torqued to 165 in/lbs (thats inch pounds not foot pounds)


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## treeboy (Jun 14, 2008)

I removed the intake valve & lapped it just to clean in up a bit. I also took .002 off the end of the stem. I put it back in and now have .006 on intake and .010 on exhaust clearance. I also repaired the spare starter, cleaned & inspected as well, should work great! I will put it back in probably on Sat., try it again & keep my fingers crossed. What about the rings? Don't think there is much I can do there without removing the engine & breaking it all down. Just keep my fingers crossed. Thanks
Al


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## phillipmc (Jan 27, 2008)

Well while the cylinder head is off i would inspect the cylinder walls carefully for any scoring. If you dont see any then when everything is clean seal the palm of your hand over the piston port and slowly turn the engine so the piston is on a down stroke. You should feel a bit suction on your hand. If you do then more then likely your rings are fine.


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## treeboy (Jun 14, 2008)

I finally got some time to work on it again. Swapped starters, reinstalled carb & muffler. Sprayed ether in and it fired right up almost immediately. Night & day between old starter and the one I went through. That faster crank speed probably helped the spark become stronger and the valve stem shaving and seat lapping all helped. Still not sure of which one in particular helped the most? Now I have to try to figure out the govenor arrangement. It wants to run full throttle all the time. I put a small spring on the throttle butterfly to force it back down but now its either all or nothing (idle), depending on the throttle lever position. Any idea where that shaft with the govenor's arm is attached in the engine? I saw no visible fan vane under the schroud? It must be some sort of internal centrifical arrangement? Seems like a sensitive little pain in the ass to try an adjust, especially if you don't even know how it works. Thanks Guys
Al


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## phillipmc (Jan 27, 2008)

their should be a lever under the plate where the throttle cable connects to. with a spring coming from the plate to the lever. A rode connects from that lever to the throttle butterfly on the carb. You will need to do a static adjustment. With the engine shut off. And everything hooked up correctly, Move the lever so the throttle is in the wide open position the lever should turn a little shaft with a 3/8 nut going through the lever. Take note which direction the shaft turns when you move the lever to the wide open position
loosen that 3/8 nut and move the little rod all the way in the same direction till it stops. Double check your throttle and make sure its still in the wide opening position and tighten down the 3/8 bolt again. This should solve your engine speed problem. ( just a hint if you cant figure out which holes the spring or rod that connects the throttle on the carb to the govenor lever look for a slit bit of wear in the holes. )


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