24HP V-Twin B&S - Fault driving me CRAZY!

[Neo7]

don't know if anyone addressed this but shutting the ignition down at RPM fills the exhaust and muffler, as well as the air at the end of the muffler with a ready to ignite mixture of gas and air. All it needs is a spark of static, piece of glowing carbon etc to set it off. That is probably the flash you saw.

Ok ... so could that be a knock on effect of an Exhaust valve closing late?

I used to have an old ford falcon with a rusty old exhaust system (and generator, non locking column, & stick shift that allowed me to do this). I'd turn the key off for about 5 to 7 seconds when someone was tailgating, turn the key back on and the exhaust would send out a shower of carbon and rust flakes that guaranteed they would not tailgate. Sounded like a small cannon going off too when I'd do it.

Love this story :laughing:

 

[Boudreaux In Eunice La.]

Bert's quote............ Double check the height of the valves from the floor of the rocker chamber, they all should be the same.
However if a guide has slipped then the valve would open latter & close earlier ( or visa versa ) .
There are a couple of Briggs master techs on here, Walt is particularly good.
The right exhaust cam is worn..........

Yes that is something to be checked out also, A valve guide that has slipped, usually when that happens it bends a push rod...... But you have the cam already being shipped to you so before splitting the engine and installing the cam go ahead and pull the offending head off and check it........

Plus tard Mon Ami ~!~!

 

[Neo7]

Ok ... I'd rather just pull the engine out (doesn't take long) and remove the crankcase cover ..... mainly because I've not ordered any head gaskets.
Is there any other way to check the valve guides without removing the head? .... Like putting the piston at TDC and pushing off the valve springs. Then checking the play (wobble) on each Valve stem?
Remembering the compression test was very good on both Cylinders. Wouldn't a slipped valve guides affect compression?

 

[Boudreaux In Eunice La.]

Ok ... I'd rather just pull the engine out (doesn't take long) and remove the crankcase cover ..... mainly because I've not ordered any head gaskets.
Is there any other way to check the valve guides without removing the head? .... Like putting the piston at TDC and pushing off the valve springs. Then checking the play (wobble) on each Valve stem?
Remembering the compression test was very good on both Cylinders. Wouldn't a slipped valve guides affect compression?

The only way a slipped guide will affect compression is if it not letting the valve open at all........

 

[Neo7]

So can I check for slipped guides with the heads on in any way?

 

[Neo7]

Ok I have taken a step back .... (Kinda got the feeling I was ordering parts without confirming they're required) and Have canceled my order with the supplier.
Now can someone please tell me how do I check the valve seat with or without pulling off the head?

 

[Boudreaux In Eunice La.]

Ok I have taken a step back .... (Kinda got the feeling I was ordering parts without confirming they're required) and Have canceled my order with the supplier.
Now can someone please tell me how do I check the valve seat with or without pulling off the head?

Well Mon Ami the only real way to check the valve guides are to pull the head off.... I will post a link to a video showing the correct way to determine if it is out of place ....

Stand by for a few ..........

 

[Boudreaux In Eunice La.]

Ok i found it Now you can watch the entire video are skip to the 18 minute mark..... I would watch the whole video....

https://youtu.be/Pl5vNccJwQs

Plus Tard Mon Ami ...... Hope this helps ............

 

[Neo7]

Ok i found it Now you can watch the entire video are skip to the 18 minute mark..... I would watch the whole video....
https://youtu.be/Pl5vNccJwQs
Plus Tard Mon Ami ...... Hope this helps ............

Ok thanks. Since my last post I've watched the video and I've also removed my valve springs. I did them one by one with the head still on, by feeding rope into the cylinders and gently bringing the piston up to keep the valves in place.

So from the compartment, comparing left to right cylinders, I can see both inlet and exhaust seats are the same height (L-Inlet to R-Inlet and L-Exhaust to R-Exhaust). And in comparison to the video I can see that if my valve seats have moved they've done so by only a very small amount and to exactly the same level left and right (I believe that would be very unlikely).

Also lining up with the peak of each cam lobe I measured the height of the rod to a straight line (steel rule) across the rocker cover mounting surface. I used vernier calipers and here's the results...

Left-ExhOpen - 19.1mm
Right-ExhOpen - 18.2mm
Left-InlOpen - 18.2mm
Right-InlOpen - 16.8

If the lobes are all supposed to have the same lift then that Right-Inlet is not good, so again it's looking like I'm going to leave the heads on and replace the cam?


Thanks
Neo

 

[Boudreaux In Eunice La.]

Might as well buy 2 head gaskets and lap the valves...... If you took the springs off while the head or heads were off then you gonna play hell getting the springs back on.......... Valves could be one more issue with backfiring.... I think you should lap the valves and reset them then>>>>>> put the heads back on and try it.... Stay away from throwing parts inside the engine..... Backfiring usually means that the valve train is the issue..... Whether it be a slipped guide a bad or dirty valve that needs to be lapped or a cam that's bad not moving the valves as they should be moving.... Or a bent push rod >>>>>>>>>

Let us know Mon Ami ~!~!