Small engine trouble

[4spdcuda66]

I have a 14 horse Briggs & Stratton OHV engine in my lawn tractor. Last fall when I was mulching leaves, one of the throttle plate screws worked loose and found its way into the cylinder. I lost all throttle control, so I pulled the carb and found that the screw was missing. There was no noise or any other indication that anything was wrong except for the loss of throttle control.

Now that the weather has turned decent here in the frigid Mid-West, I pulled the head and found this piston and combustion chamber damage. I found no sign of the errant throttle plate screw. Would I be safe to file down the damaged surfaces to free them of sharp edges, then re-gasket and install new throttle plate screws (with thread locker) and button it back up and run it? There don't seem to be any cracks or deep gouges, and the valves are sealing well. I checked with kerosene and they held the liquid. What do you think?

 

[RustyRatRod]

Hell yeah. Clean it up. That'll ride.

 

[diymirage]

I would do a quick plate sand to get her smooth and level and button her up

 

[4spdcuda66]

You guys are great! Always telling me what I want to hear!!

 

[chryslerfat]

You guys are great! Always telling me what I want to hear!!

They have learned from years of being married. Tell em what they want to hear and dinner is good.

 

[4spdcuda66]

They have learned from years of being married. Tell em what they want to hear and dinner is good.

HA! That's real world experience for sure! :laughing:

 

[TrailBeast]

If the cylinder isn't banged up it'll be fine.
Being a small engine I don't think I would even bother trying to clean up the top of that piston.
I would pay attention where this spot is damaged though, as it looks like the screw got into the compression ring area a bit.

 

[ScampMike]

dang thing did some bumping around in there... new gaskets and proper torque specs - like RRR said - that'll ride.. and like TB said - check the piston closely for ring damage -although you did say no leak down... I'd bet you'll be fine

 

[TrailBeast]

dang thing did some bumping around in there... new gaskets and proper torque specs - like RRR said - that'll ride.. and like TB said - check the piston closely for ring damage -although you did say no leak down... I'd bet you'll be fine

I said as long as the cylinder didn't get beat up, and that dent right where it looks like the sealing metal ring of the head gasket sits.

Or what I meant anyway.

 

[ScampMike]

yes you did - me doing 3 things at once... didn't read and comprehend before I replied.. yea, scoring in the cylinder would be bad. (notice I didn't say 2 things at once.. 'cause.. you know.. anyone can do two things at once... and not fudge them up.. LOL)

I said as long as the cylinder didn't get beat up, and that dent right where it looks like the sealing metal ring of the head gasket sits.

Or what I meant anyway.

 

[TrailBeast]

yes you did - me doing 3 things at once...

Believe me, I know how that is.
I think it's actually become my lifestyle.

 

[4spdcuda66]

If the cylinder isn't banged up it'll be fine.
Being a small engine I don't think I would even bother trying to clean up the top of that piston.
I would pay attention where this spot is damaged though, as it looks like the screw got into the compression ring area a bit.

The cylinder looks good. I didn't see any damage at all inside. The part that you circled is about a business card thickness inside the gasket sealing surface. I noticed that spot right away and checked it with the gasket. The gasket was undamaged as well.

 

[mguner]

I would pull the piston just to make sure the top ring is free in the groove. It may need a little TLC as well.

 

[RustyRatRod]

If the cylinder isn't banged up it'll be fine.
Being a small engine I don't think I would even bother trying to clean up the top of that piston.
I would pay attention where this spot is damaged though, as it looks like the screw got into the compression ring area a bit.

Great eye! I tell you what.....I wouldn't even be afraid to clean that up real good, file any sharp edges off and fill it in with JB Weld. Not like it's goin anywhere and all you need is a flat surface for the gasket to seal on.

 

[RustyRatRod]

The cylinder looks good. I didn't see any damage at all inside. The part that you circled is about a business card thickness inside the gasket sealing surface. I noticed that spot right away and checked it with the gasket. The gasket was undamaged as well.

If the gasket was unhurt, then it might ride just like it is without any attention at all to that spot.

 

[4spdcuda66]

Cleaned everything up, dressed those damaged areas and ran the mating surface over 220 grit on a sheet of glass. Picked up a new gasket and layed it over the mating surface. Looks pretty good. Going to work on it some tomorrow. Hope to have her running in the next day or two. You can see in the photos that one suspect area is OK.

 

[4spdcuda66]

Cleaned everything up, installed a new gasket, set valve lash, put in new throttle plate screws with thread locker, put in a new spark plug, changed the oil and took her for a test run. She pulls as strong as ever! Now I need to do a few repairs on the hood where it bolts to the frame. The metal is really thin there, so I'm going to make some reinforcement plates and put her all back together. She's all good to go for tall grass season!! Thanks for all your support, FABO friends!

 

[TrailBeast]

Sweet.