Valves move up and down together, in unison, is this right? Video attached

[abicer81]

I have a friends pressure washer with the 775 professional series engine (#'s 11P902-0120-B1, 10072662) that now refuses to start upon shutting off after normal run. It was used for 30 min on the first run (practically brand new), shut down and now it doesn't start. I pulled apart the carb and it was full of dirt. I replaced it with an OEM briggs carb. Still no luck. It will putt once in a while but from the intake and not the muffler, the only indication of combustion. I took a video to a local repair shop and the tech says it looks like timing. Now they're closed for a week for the 4th and he's out of the equation. So I pulled off the valve cover and set the piston to tdc. Turning the crank in either direction from here causes the valves to move up and down at almost exactly the same time. I have attached a video. Should they not move alternately rather than both at the same time? I refuse to give up. This has become a personal war with this machine that I intend to win lol. I've been messing with it for the last 8 hours and now I'm stuck. All help will be tremendously appreciated!

 

[Midniteoyl]

This is new? Still under warranty?

And no, the valves should move at different time like a normal 4 stroke. https://www.partstree.com/parts/bri...al-piston-rings-connecting-rod-warning-label/ shows the cam and part#. I never had one of these apart, so dont know if they have have pressed on lobes, or are cast., but, looking at it, it seems like they are pressed on and one moved.

Heres one for $41 free shipping w/prime: https://www.amazon.com/Briggs-Stratton-694039-Camshaft-Replacement/dp/B005F6QY90

 

[bertsmobile1]

:welcome:

I find your story a tad on the suspect side
The only way that can happen is for both of the pushrods to be working on the same cam follower.
If that be the case one of the pushrods would be at such an angle that it would fall off the second the load from the valve spring was released.

There is a small chance that it can be reassembled to that state but there is next to no chance of it "just happening" like that.

In any case the pushrods will have to come out & be checked at a minimum.

 

[primerbulb120]

I have a friends pressure washer with the 775 professional series engine (#'s 11P902-0120-B1, 10072662) that now refuses to start upon shutting off after normal run. It was used for 30 min on the first run (practically brand new), shut down and now it doesn't start. I pulled apart the carb and it was full of dirt. I replaced it with an OEM briggs carb. Still no luck. It will putt once in a while but from the intake and not the muffler, the only indication of combustion. I took a video to a local repair shop and the tech says it looks like timing. Now they're closed for a week for the 4th and he's out of the equation. So I pulled off the valve cover and set the piston to tdc. Turning the crank in either direction from here causes the valves to move up and down at almost exactly the same time. I have attached a video. Should they not move alternately rather than both at the same time? I refuse to give up. This has become a personal war with this machine that I intend to win lol. I've been messing with it for the last 8 hours and now I'm stuck. All help will be tremendously appreciated!

Here's a cam gear for $27. It's OEM. http://www.ebay.com/itm/NEW-BRIGGS-...3131?hash=item5b25fb0a6b:g:xDUAAOSwnFZXWiK 7

 

[abicer81]

This is new? Still under warranty?

And no, the valves should move at different time like a normal 4 stroke. https://www.partstree.com/parts/bri...al-piston-rings-connecting-rod-warning-label/ shows the cam and part#. I never had one of these apart, so dont know if they have have pressed on lobes, or are cast., but, looking at it, it seems like they are pressed on and one moved.

Heres one for $41 free shipping w/prime: https://www.amazon.com/Briggs-Stratton-694039-Camshaft-Replacement/dp/B005F6QY90

Thanks for the input. As for warranty, it's expired. It didn't get it's first use until almost 2 years after purchase. I'm leaning in the same direction, a pressed on lobe that moved. Time to take it apart. Thanks again!!

 

[abicer81]

:welcome:

I find your story a tad on the suspect side
The only way that can happen is for both of the pushrods to be working on the same cam follower.
If that be the case one of the pushrods would be at such an angle that it would fall off the second the load from the valve spring was released.

There is a small chance that it can be reassembled to that state but there is next to no chance of it "just happening" like that.

In any case the pushrods will have to come out & be checked at a minimum.

Suspect? How so? as Midniteoyl suggested, It's likely the lobes are not milled into the camshaft but rather pressed on or attached in some other manner. Only way to find out is to take it apart at this point.

 

[abicer81]

Here's a cam gear for $27. It's OEM. http://www.ebay.com/itm/NEW-BRIGGS-...3131?hash=item5b25fb0a6b:g:xDUAAOSwnFZXWiK 7

Thank you, I appreciate that

 

[mhavanti]

Seen this before. Camshaft broke, engine made one last revolution before the camshaft hung 180 and now both lobes are close to the same degree relative to the crankshaft. If you're lucky, it didn't do any damage to the crankcase and all you'll need is to replace the bearings, camshaft and gasket set.

Let us all know what you find when you split the case.

Good luck.

 

[bertsmobile1]

Well there you go.
The only lobe failures that have come into this workshop the lobe stripped thus did not turn with camshaft at all & I have only seen 2 of them
The most usual failure is a couple of the teeth break out due to hitting a rock of a big back fire, although no one ever admits to hitting rock.
A few have come in after a service trying to claim a service warrantee repair. Thus the suspicion to claim that it just happened all by itself.

 

[abicer81]

Seen this before. Camshaft broke, engine made one last revolution before the camshaft hung 180 and now both lobes are close to the same degree relative to the crankshaft. If you're lucky, it didn't do any damage to the crankcase and all you'll need is to replace the bearings, camshaft and gasket set.

Let us all know what you find when you split the case.

Good luck.

Thank you. I'm going to crack her open now and see what the insides look like.