# Tiller is down!



## remauto1187 (Apr 9, 2011)

WOW these Briggs & Strattons aren't anything like what i worked on 25yrs ago. I have a Bolens tiller with a 6.0hp 126402-0261-E1 (stamped on valve cover). Tiller was purchased in 2003 brand new by me and has less than 5 engine hrs on the clock.

Tiller was hard starting last year then always ran like crap for awhile then just would not start. Cleaned carb out, emery clothed flywheel and coil. Getting spark and gas just fine. Tried to start with choke on and got a pop once in awhile. Sounded like alot of the compression was coming out of the carburetor.
So i pulled the valve cover and sure enough the valves are NOT moving at all. They are not stuck. (I can push down on the rockers and the valves move freely). What on earth could be the fault here? Piston travels up/down so flywheel key should be fine?

This engine has never had any service of any kind (other than carb clean and oil changes yearly).

Cam and crank are direct driven gear to gear on these right?


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## justin3 (Apr 10, 2007)

The difference between Briggs and Stratton today and Briggs and Stratton 25 years ago is that today Briggs is using Nylon camshafts in some of its lower class engines. You need to pull the crankcase cover off of the engine and you will probably find broken cam teeth or worn lobes on the shaft itself. Also check your push rods to make sure they are not bent. When installing the new cam you need to line the dots up on the gear and crankshaft, its not that hard of a job if your handy. The camshaft is about $45 plus gaskets and crank gear if you need that too.


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## remauto1187 (Apr 9, 2011)

Seriously? The camshaft in this thing is nylon? So no timing chain...direct drive metal crank gear to nylon cam gear? WOW! They sure don't make stuff like they use to!

Yeah i am in the middle of building a corvette LS6 engine for my '85 Vette so i sure hope this tiller doesn't embarras me!

If the diagram i was looking at on the Briggs site was correct. I can just pull the crankcase cover off and just have to replace its gasket and the PTO Side oil seal, correct? And of course the cam itself. 
Loosen rockers and cam will slide right out, correct?


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## 30yearTech (Sep 14, 2006)

Check the valve lash before tearing down your engine, and have a look at the push rods as justin3 suggested. For the most part, the nylon cam gear setup is pretty reliable, but can on occasion fail. 

If you align the timing marks you can pull the cam out with out loosening the rockers. Just be sure the engine is not upright or the lifters and push rods will fall into the crankcase. If you replace the camshaft, you will need to reset the valve lash anyways.


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## remauto1187 (Apr 9, 2011)

While turning flywheel over i do not feel any upward movement at all on the pushrods (both I and E). If they were bent i still should be able to feel some movement, right?

What are the specs for my lash on my engine and what is the spec measured at? Exact TDC?


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## 30yearTech (Sep 14, 2006)

Intake .004" - .006"

Exhaust .009" - .011"

Valves are set at 1/4" past TDC on power stroke. Of course if you can't get either valve to move, then you won't be able to determine which stroke the engine is on. This being the case, I think it's time to pull the sump cover off and have a look at the camshaft to see what's going on.


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## remauto1187 (Apr 9, 2011)

Yeah i wanted the valve specs for later when i put it back together. Thanks!

I went out to the monster this morning and noticed an odd symptom. If i slightly turned the flywheel backwards the valves would move as normal! So then i got to thinking that of course the cam is the culprit. So i pulled the sump cover off (took about 10minutes) and after removing rocker arms and pushrods...sure enough.....Its the cam that is junk! The nylon driven gear is split on the shaft of the cam. The gear spins one way but reverse it moves about 1/4" or so then lock solid to the shaft of the cam. No wonder the valves "worked" turning the engine reverse.



In the Illustrated parts list on the B&S site they list 2 cam part numbers and show 2 pics. One is like mine with the spoke center of the driven gear (nylon) and then the other appears to be solid in pics with no spoke. Is this one a solid metal type? They both are the same price too. Part numbers are.....
Part# 693404 - Camshaft $40.10 (spoke like mine)
Part# 695285 - Camshaft $40.10 (appears to be solid) unknown construction material.


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## 30yearTech (Sep 14, 2006)

693404 is the correct cam for your engine, the 695285 is probably all metal construction, but would require modification to work in your engine. From the illustration, it looks to have an extended shaft. This is for for applications that drive off the camshaft rotation. The sump used on this engine would be open all the way through with an oil seal for the camshaft to extend through. Tulsa Engine Warehouse shows the 693404 for $36.09.


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## remauto1187 (Apr 9, 2011)

Oops i forgot to align crank timing mark before i pulled cam. Im betting this will make a difference to which 180degree of crank rotation i use for TDC with respect to where the flywheel magnet is. Should the magnet be at the coil or 180 degree away (the one on the flywheel) for TDC?


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## 30yearTech (Sep 14, 2006)

remauto1187 said:


> Oops i forgot to align crank timing mark before i pulled cam. Im betting this will make a difference to which 180degree of crank rotation i use for TDC with respect to where the flywheel magnet is. Should the magnet be at the coil or 180 degree away (the one on the flywheel) for TDC?


Nope! Crankshaft is solid, and the flywheel attached to it rotates with the crankshaft. The magnets are in the same location with regards to timing every time the crankshaft is rotated. The magnets are always going to be near the coil whenever the piston is near TDC. The ignition sparks on every single rotation of the engine, but power is only produced every other revolution. Timing marks are for valve timing only, ignition is timed with a key between the flywheel and crankshaft.

Line up the timing marks when you install the new camshaft, set the valve lash and you will be good to go.


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## remauto1187 (Apr 9, 2011)

Ahh i see. Now that i actually spun it and watched the locations. You are right.

Hope i get my parts soon.....before i forget how to put it back together and manage to lose that last bolt that needs to go in. 

Thanks for the info 30yr!


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## justin3 (Apr 10, 2007)

Glad to see you got it figured out! In some model engines you can cross referance to an older version of your motor and find an all metal cam, for example when I rebuilt the motor in my snapper, I replaced the nylon cam with an all metal cam from a used engine. Same horsepower and series, just an older model.


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## remauto1187 (Apr 9, 2011)

Yeah i kind of figured that. Unfortunately I dont have time to do the research to find the metal version that will work for me. (But i sure wish i did). I gotta get parts ordered up tomorrow and hopefully have them well before Friday so i can get this motor back together and get this tiller put to work. And now that i own 5 acres I am gonna get my moneys worth out of this tiller. I hope to get enough pumpkins and watermelons alone to pay atleast 2 of my house payments at the end of fall and stock my deep freezers with vegetables to cut down on the grocery bills.

I appreciate everyones help and my hat is off to you all for giving help to others ...for free.

Thats the way i like to work as well, but my specialty is electrical and electronics and automotive.

I am a Federal Aviation Administration electronic tech and former US NAVY Aviation Electrician (VFA-37 F/A-18C Hornet).


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## remauto1187 (Apr 9, 2011)

Tiller is all back together. Thanks goes out to justin and 30yr. Tulsa Engine Warehouse is a great source for parts, great service and fast shipping.

Tiller fires up and purrs like a kitten on the first pull everytime. Pulls great under load. Runs like new! 

Hope the rain gives me a break this weekend so i can start breaking some ground!

Thanks again gentleman! :thumbsup:


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