Bent push rods and Mower belts - lawn tractor

[348tripower]

Bought 2 belts at Lowes... they had them on the hook.  One number was exact, other was a cross over I found online. 30 dollars each, but the mower operates again.

I even took the time to grease stuff and air up the tires.

Sounds like I have an exhaust leak or loose valves.  Quiets down as the engine warms up

Kohler twin? Mine does the same thing. Sounds like it is coming apart when you start it cold.

I have a twin and as you can probably recall he was noisy too.

[enjenjo]

I have a twin and as you can probably recall he was noisy too.

   

[Crosley.In.AZ]

well....  all was OK for a few minutes into the next mowing session.  Engine was down on power slightly and noise was back.

Pulled the rocker covers again.  Both exhaust steel  pushrods are bent. Intake rods are aluminum, not bent, slight curve.

From what I read on line these Briggs Intek motors bend push rods and some fellows that seem to know, suggest Steel pushrods on both valves.

I ordered up 4 steel pushrods at 3 bucks each.  At that price, they may not be too strong.  LOL

[jaybee]

Seems like a weird thing to make from aluminum.  Steel would seem to fit the purpose better.

Thanks from me also for the Gates link.  I need a new belt for my air compressor.  The old one came apart not long ago and I'm already sick of listening to the oiless running right in the shop with me.  That's why I didn't get rid of it though, to have a spare and (relative) portability.  Came in handy this weekend as I did some trim work inside the house, too.

[Crosley.In.AZ]

well... the second page of the story.

Lawn tractor ran fine for 2 yard mows. Keep in mind the yard is about 1/2 an acre. Then the engine went to one cylinder and blowing exhaust out the air filter.

Both exhaust push rods bent again.  More research and I discover the valve guides on exhaust have move out. Spring retainers hitting the guides, equals  bent push rods.

On line forums tell of buying new heads for the Briggs twin cylinder. I rejected that nonsense because the heads have not  been  redesigned.

I machined a little aluminum tool, removed the valve springs and rocker arms. With air pressure in the cylinders, I pushed the guides back in with my little aluminum tool and a hammer.

Then I drilled down the side of the valve guide and head castings. I then tapped the hole for a small set screw and a little bit of green loctite to hold the valve guide in place.

New push rods installed, valve clearance at the rockers set at .005 and .007 , the engine runs good.

I also gave the engine a very intense steam cleaning, it seems the thermal coating built up of oil and dirt can cause the ol Briggs to run warm.

I just mowed the yards at full governor WOT RPM.... the ol lawn tractor mows like a muther again.

The retirement location yard work will involve spraying grass killer and diesel fuel on anything that wants to grow too much.

[Dusty]

Crosley...

I have the Briggs V-Twin on a Sears type mower.  I had the same problem with one cylinder, and I ordered new pushrods, only to have them bend also.  What I found out was that the valve guide had slipped out and was too high, and the rocker came down to open the valve and was limited by the extended valve guide.  I drove it back in with some epoxy glue.  It held for several mows, then it broke loose and forced the rocker arm to pull the mounting stud out of the head.  Those heads are expensive.  I solved it by pulling the guide all the way out, roughing it up and using JB weld, I drove in back in and pinned it at an angle through the side of the boss.  On the rocker arm stud, I just drilled through that part of the head, and put a nut on the end of a longer bolt, and that was 2 years ago.  If you look on the head, where the rocker stud goes in is out to the side of the combustion chamber...Gud Luk...