# Help with a B&S model 28N777 (9642-A1)



## donq12 (Feb 25, 2007)

Ok I am at my (rather short) wits end. I need to pick the brains of some of you guru's if I can.

I have a B&S
model 28N777 
type 0642-a1
code 961016z0

I lost a small piece that is in the valve train and I need to replace it, the problem? According to all B&S manuals/parts lists etc, IT does not exist !

The end of the valve (i and exhaust) that touches the rocker arm is different on mine than in all drawings ! The B&S literature shows the standard "split ring keeper and valve cap (round plate that sits on top of the springs) that is what I have seen all my life and is in all the drawings,

MINE has a weird looking "offset round cap that has a small hole that locks the spring onto the valve stem..NOTE item # 42 listed as VALVE-KEEPER on B&s drawings)" sorry for bad description. 

on MY motor the KEEPER (round plate) has a larger hole beside the centered hole that allows you to place this "keeper plate" onto the valve stem, then rotate the plate until the smaller centered hole locks the assembly together. IT DOES NOT hAVE THE SPLIT-KEEPER RING . I can find NOTHING like this in the B&S literature. Is this a twilight zone deal or?

Any/all help appreciated. I have spent days trying to unravel this before posting the question and am about to lose my mind. I have tried 3 dealers, they all drag out the same drawing/parts list that I have (from B&S) that shows the normal split-ring-keeper and cap. When I tell them no, thats not what I have they scratch their heads and order the same split-keeper the drawing shows ..

BTW The missing part is a "mall steel cap" that just sits on the end of the valve stem (the rocker arm end of course) this caps is between the end of the valve stem and the rocker arm. Both my intake and exhaust valves have these caps (well, at least they did before I lost one  and I really need to find/order/dream one up.

Does anyone know/have you seen this valve-cap I seek? IS IT POSSIBLE MY ENGINE IS MIS-MARKED? I got all info from the "plate riveted to the motor" . this is YARDMAN riding mower . 15.5 HP is on the engine.
If it helps .. this missing steel cap is slightly larger than the vlave stem, it has a recessed hole that the vlave stem sits in that is (guessing) 1/16" deep and the cap is about 1/8" long..( picture a soda bottle top but in steel)

Thank you for looking and all help appreciated,

Rande Pate


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## 30yearTech (Sep 14, 2006)

Is it possible that someone has replaced the keepers on the valves before? What you describe sounds like the keepers that are used on L-Head engines without the rotator cap.


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## donq12 (Feb 25, 2007)

*L-head question*

As far as I know this is a "factory standard, never worked on" motor", but tghats possibly incorrect.

If you would post the model number of any l-head engine (sorry but I don't know any other way) will go lookup these l-head motorsa and see if its the saME. The B&S site is great but you better have a model # in mind to find anything..

Thanks

Rande


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## donq12 (Feb 25, 2007)

After a bit of research I find that this is not an L-HEAD motor. AT least I think not, I looked up l-head and saw many references to "valves in block" .. this is definately a OHV motor, in fact its stamped on the valve cover 

This thing is really driving me nuts now. If no one has ever seen a 15.5 hp briggs with the valving arrangement I described (maybe I have a "unique motor" (you know, the kind you have to "neak" up on to see ) .. seriously tho ..

If anyone has seen the described valve keeping setup I mentioned and has the model # and series number (the two items that keep you from going any further on the B&S site without) PLEASE post .. I just need to view a diagram that has this valve keeper setup so I can start to locate this part i need .. many thanks

Rande


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## donq12 (Feb 25, 2007)

If all went well you can view the valve problem in question under the pictures on this site

Location :misc items
Name BS_model28N777

I hope that helps solve this mystery


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## 30yearTech (Sep 14, 2006)

Perhaps that is the way they originally came, with the keeper you lost. The keeper shown in the parts diagram should work just as well (p/n 499586) it just installs a little differently then the one that was on it.

I have worked on engines in the past that had a cap on the end of the valve, I don't know why this break down shows something different, unless they have changed the keepers and done away with the cap. If you used the new type keeper would you still be able to adjust the valve lash to spec. 

Below is a breakdown of a slightly older engine that shows a keeper and a cap in the illustration, but the part number is the same as in your engines break down

?http://www.hobbytalk.com/bbs1/attachment.php?attachmentid=37994&stc=1
Cyl_Hd.pdf


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