Tractors, Mowers, Chippers, Trailers, Chainsaws, Generators, Driveway Erosion Control, ETC.

Keepers are doing their job.

The valve stem guide is not in its correct position.

When they do that, the valve can not be pushed down by the rocket arm because the guide is higher than it's supposed to be... Results are a bent push rod...and sourcing a new head, of course .

 

I'm confused

Explain the shiny valve stem if the keepers were not letting the cap slide up and down over the valve stem/

 

Slowly making progress on the tractor. New water pump and all new hoses are in. Major corrosion inside the cooling system. Old pump was basically an anchor lol

 

One is shiny, true. The other has carbon build up. That one is the exhaust valve keeper.

The shiny one doesn't see much heat, since it is cooled by fresh intake air.

The dark one sees a lot of heat from the heat of combustion.

The valve stem keepers are exactly where they are supposed to live. The spring cap is kept in place by the keepers.

The problem is the valve stem guide has moved up.

Now there is not enough room for the spring to compress. The spring tries to compress, but there is not enough room. The next weakest link is to bend the push rod.

The iron valve stem guides are pressed into the aluminum head.

The iron valve stems need to slide up and down on the iron guides. On occasion, the iron guides don't expand as fast as the aluminum head, this allows the iron guides to push up out of the aluminum head.

When this happens, the iron guides that are now higher than they are supposed to be causes the pushrods to bend because the spring can only compress partially.

Remember, there is a cam shaft that moves the push rods up and down. It doesn't care about froze valves. It's a much bigger chunk of iron and the pushrods are nothing for it to bend.

I hope this makes some sense.

 

Sucks but, the weak link gives. Which by design is the smaller link. Outcome sucks for the end link.

 

Nice work.

 

Briggs? Same thing that happened to my neighbors mower and it broke the push rod.

 

Yes. This one bent the push rod, too.

Got a complete head and pushrods on the way.

 

I read the cooling fins get stopped up from oil, grass, dirt, etc. and it causes the aluminum to get hotter and swell faster allowing the valve guide to move.

Exactly the problem with my neighbors mower, it was caked with stuff. I pressed the guide back in and sent it. She's been mowing with it all summer.

I told her if it did it again I would put a new head on it.

 

Saw this online, neat idea if you work on saws a lot. Able to rotate it and keep it held.

 

I'll try that with this one. Can't hurt to try.

 

Out of curiosity, was yours caked with stuff on the cooling fins?

 

Not a bit. It was extremely clean.

The story I got. She mowed the yard previously with no issues. Started the mower up a week later and she knew right away it was running wrong and smoking.

I'm trying to figure out why it would push that guide up on a cold start.

I know this is a common issue when there is a cooling issue, but this mower was debris free.

I'll probably never know.

 

That is weird. Maybe just a defect with Briggs.

 

All done and pretty.

 

Went to pickup the power house prowler this evening.
The good
-has a newer Honda GX690 engine with only 26.5 hours.
-tracks look almost brand new.
-5x10 trailer is really heavy duty.
The not so good
-couldn’t get the engine to run. Battery was dead so used my truck to jump it. Spark is good but no fuel. We were able to get it to run with starting fluid(I know, not good for the engine) but would die right away. Popped the fuel line off and the gas was milky with water in it. Added 3 gallons to see if we could get a little bit of clean fuel in it but no luck. I am thinking it’s the fuel shutoff solenoid that is bad, I can hear it click very faintly but the YouTube videos said it should be a loud click.

Going to call around tomorrow morning to see if anyone local has a fuel solenoid in stock, otherwise I will have to order one online. Will definitely need to drain all the gas and clean the carburetor but I would like to do that at my house and not in my coworkers driveway.

 

Brakes on the left side would lock up at the slightest touch of the pedals.

The pivot pin mounting stud had broken off and set things a-drift. Talk about "fully floating brakes"!

I drilled and tapped the working part of the stud to take a 1/2-20 bolt.
A special washer was needed behind the backing plate, so one was turned up to suit.

Of course, a couple of bolts lost their heads over the ordeal. Fortunately, there are stubs protruding from the cast iron. The "smoke wrench should take care of removal!

 

I've knurled the bores of valve guides to salvage wear before reaming.

It looks like this application needs knurling on the outside! ;-)

 

In a pinch, you can remove that solenoid and snip off the shut off plunger. Be aware, if your gas tank is higher than the carb, raw gas will trickle past the float and make it's way into the combustion chamber and cause a hydro lock situation.

I wish I was down there, I'd get it running for you.

Looking like mid November.

 

Can I get some details on this knurling procedure?

I'm pretty much a remove and replace guy, but do have a thirst for knew knowledge.