Briggs ELS 725 Exhaust Pushrod Issue

[davbell25413]

446677
0470-E1
050310YG

Sears GT5000 917.276310 48in cut gear drive

Got this on trade earlier this year in the spring. Diagnosed it last year in of having 3 of 4 pushrods missing and the 4th one was bent. Plus oil leak had oil leak also. Recently split crankcase and found loose crankcase bolt which is probably why it leaked oil. Found bent steel pushrod inside the crankcase but the other 2 are missing in action. Replaced all 4 pushrods and crankcase gasket. Set the valves to .005 on the compression stroke 1/4 turn past TDC as manual says too for each cylinder. When exhaust pushrod is in cylinder #2 the engine goes into a bind and bends it. Engine will roll over just fine by hand when its not in there. Exhaust valve will open by hand when using the rocker arm to open it. It will not open the exhaust valve with rocker arm instead it bends the pushrod. I set to .005 on loose side this last time when it bent the 2nd exhaust pushrod on cylinder #2. Is it possible to have a bent exhaust valve in the guide?

[KE4AVB]

Have you verified that no one else have been in the engine? If not then the aluminum push rods are there somewhere in the engine and need to be found. They can't just vanish into thin air or at least I don't think so.

Check the rocker and pivot for damage. Also check the exhaust valve guide is in it proper place; it may have worked it out or loose causing a bottoming out issue with spring assembly.

As thinking out loud. I haven't ran into this problem yet.

[davbell25413]

Yes someone else has did diagnose it before I did and told the PO that the reason it wont start cause of the PTO clutch needing replaced. Then PO called the shop after I diagnosed it last summer to question there theory of needing a PTO clutch. They told him this time it needed new engine.

I have good compression and cant keep my thumb over either of the spark plug holes. No markings on the cylinders on what I could see without removing the pistons.

[bgsengine]

Valve guide worked loose and is sticking out too far from the head, valve retainer bottoms out on it bending pushrod cause it wont go any further.

Got to pull head and remove valves to really see it.

I'd bet money that's what you'd find.

[davbell25413]

Valve guide worked loose and is sticking out too far from the head, valve retainer bottoms out on it bending pushrod cause it wont go any further.

Got to pull head and remove valves to really see it.

I'd bet money that's what you'd find.

Should I go ahead and pull both heads? I have head gaskets for this engine and OHV cover gaskets too.

[bgsengine]

If you got both gaskets, may as well pull both heads and check valve guides for height, looseness, etc. Also check piston for any dings from valve going down too far, and if none are found, most likely it is a valve guide.

[davbell25413]

Ok, Here's pic of the steel pushrod that I found inside the crankscase on top the camshaft.

http://i938.photobucket.com/albums/ad22 ... l6p7rn.jpg

[davbell25413]

I got back on this issue. How far out is the valve guide suppose to stick out on the head?

[bgsengine]

I got back on this issue. How far out is the valve guide suppose to stick out on the head?

If it moved, you'll see it - better yet, post a pic.

[davbell25413]

Here's pic of cylinder #2 head. I dont see any signs of the guide moving. Its in the same place like the one on cylinder #1. So maybe its something I did wrong again.

http://i938.photobucket.com/albums/ad22 ... q9wczf.jpg

http://i938.photobucket.com/albums/ad22 ... kzmgy3.jpg