Briggs and Statton Backfires through carb

[RandyT]

Update. I found my problem Bent push rod. Thank you everybody for your suggestions. Now the fun begins

Now look very closely inside of that valve spring. Make sure the guide is the same height as the valve guide on the other valve. If the head overheats it will cause the valve guides to migrate toward the valve keepers which then get to a point that they will prevent the valve from opening which is the cause of the bent push rods most of the time.

 

[Southern Comfort]

Thank you. Do you think I should pull the head and make sure there isn't any damage to the valve or piston

 

[RandyT]

Thank you. Do you think I should pull the head and make sure there isn't any damage to the valve or piston

As long as the valve guides haven't moved toward the valve keeper where they will prevent the valves from fully opening and bending another push rod, the valve and piston and cylinder should be fine.

 

[Southern Comfort]

The valve guide has moved and there is no indication that there ever was a valve seal on that valve. On the parts supplier web sites I don't see a listing for the valve guides for my engine. Do you know if this guide is replaceable.

 

[RandyT]

The valve guide has moved and there is no indication that there ever was a valve seal on that valve. On the parts supplier web sites I don't see a listing for the valve guides for my engine. Do you know if this guide is replaceable.

Only the intake valve would have a valve seal. And the guides are not replaceable.

 

[arto98607]

Sorry for the trouble - I thought these were pretty good engines?

Your post caught my attention since I also have a Vanguard engine in a Vermeer SC362 stump cutter.

It's a 35 hp 993 cc engine with about 800 hours on, and as one would expect it's a pretty tough service in stump grinder!


Question: Does your engine have an oil cooler (see the red arrow)?

 

[Southern Comfort]

No, my Eng doesn't have an oil cooler. Mine is in a Husqvarna lawn Tractor 24hp. Trying to find a way to repair a valve guide that has moved. I was thinking of trying Loctite

 

[etpm]

No, my Eng doesn't have an oil cooler. Mine is in a Husqvarna lawn Tractor 24hp. Trying to find a way to repair a valve guide that has moved. I was thinking of trying Loctite

Loctite needs some space to work. If the guide fits the hole with with no space between the guide and the head when the guide is pressed in the Loctite will just be wiped off. You could file a groove for the Loctite in the guide and then press the guide in. The groove needs to be only a few thousandths deep. The green (#609? I forget) Loctite for cylindrical parts loses its hold completely at about 450 degrees F. It does start to weaken at about 400 degrees.
Eric

 

[RandyT]

Sorry for the trouble - I thought these were pretty good engines?

Your post caught my attention since I also have a Vanguard engine in a Vermeer SC362 stump cutter.

It's a 35 hp 993 cc engine with about 800 hours on, and as one would expect it's a pretty tough service in stump grinder!


Question: Does your engine have an oil cooler (see the red arrow)?

View attachment 879939

The Vanguard isn't the same engine as the OP which is the Intek series. The Intek is more of a 750-1000 hour homeowner engine where the Vanguard is a commercial rated 1500-2000 hour engine.

 

[RandyT]

No, my Eng doesn't have an oil cooler. Mine is in a Husqvarna lawn Tractor 24hp. Trying to find a way to repair a valve guide that has moved. I was thinking of trying Loctite

There are a few people out there that have pressed them back into place and found a way to lock them there. If the attempt fails the guide will migrate back out and cause another bent push rod or worse end up in the crankcase. If the repair fails you will know in about an hour of operation.