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I have a Craftsman 21HP 42" riding mower. It has a B&S engine 461707, type 0147-E1. Is this an OHV engine? Where is the valve cover? I cannot find it and want to adjust the valves. Thank you.

Sorry for being blunt, but if you have to ask for help finding the valve covers, you probably should not be adjusting the valves.

First it is not an OHV engine but is a vertical opposed. Adjusting the valves is a lot harder than an OHV as the heads, breather covers, and valves needs removing once the clearance are check and found not in specs. Adjusting consists of filing the valve stem tip squarely and you are at should go ahead and do a full valve job. These breather cover are on the cylinder and are facing the intake side. You will a valve spring compressing tool just the remove the valves.

why do you want to adjust the valves, i know it's usually specified doing it every certain amount of hours, is it starting hard? low compression? timing off?

Thanks for the replies. No problem being blunt. I do almost all my own servicing of vehicles and engines but know less about small engines. My mower finds it hard to crank the engine, even with a good, fully charged battery and has done so for a long time. The symptom fits valves needing adjustment and doing so on OHV is quite simple but no OHV cover was evident. Before going further I thought I would ask for advice here.

Unless I am able to find a good video somewhere like YouTube I will likely just put it in to be done. I hate doing that when I have ability and all the tools but not the knowledge.

Could be the starter too.

OHV & SV engines wear differently.
On OHV engines the valve lash increases thus defeating the decompressor
On SV engines the valve lash reduces due to wear on the valve seat so it effectively reduces the valve lash and reduces the compression period.
When a SV engine shows signs of lumpy cranking it generally means time for a new cam
OTOH if that is a very old engine the starter may be in need of a service, new brushes make an amazing difference
It also could be suffering from corrosion INSIDE the battery cables so try cranking the engine directly from the battery using jumper leads.

OHV = Over Head Valve
OHC = Over Head Cam
SV = Side valve = L-head.

If the op is having problems with this Opposed engine starting as describe it is more likely a worn out starter which is likely worn bushings. It is cheaper to just replace the starter with a good after market starter.

Briggs Twin Cylinder L-Head Service Manual

StarTech said:

OHV = Over Head Valve
OHC = Over Head Cam
SV = Side valve = L-head.

If the op is having problems with this Opposed engine starting as describe it is more likely a worn out starter which is likely worn bushings. It is cheaper to just replace the starter with a good after market starter.

Briggs Twin Cylinder L-Head Service Manual

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Makes sense. Thank you.

StarTech said:

If the op is having problems with this Opposed engine starting as describe it is more likely a worn out starter which is likely worn bushings.

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► Yes, it could be increased mechanical friction inside the starter due to worn parts or solidified (oxidized) bearing grease.
► It could also be poor electrical conditions where the starter relay has burned contacts internally and is not allowing full battery current to pass to the starter motor.

More testing is required.

cpurvis said:

Sorry for being blunt, but if you have to ask for help finding the valve covers, you probably should not be adjusting the valves.

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I was going to post the SAME !!!

Scrubcadet10 said:

Could be the starter too.

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I would say starter also, those opposed twin Briggs are pretty solid and rairley need valve work.

Born2Mow said:

► Yes, it could be increased mechanical friction inside the starter due to worn parts or solidified (oxidized) bearing grease.
► It could also be poor electrical conditions where the starter relay has burned contacts internally and is not allowing full battery current to pass to the starter motor.

More testing is required.

Click to expand...

Testing is good way to eliminate problem and to verify that someone is on the right track. With voltage drop tests you can be surprised at what is causing the problem sometimes. Just recently I had a bad battery terminal that cause problems as the voltage only dropped out under load. What strange was the fuel solenoid never dropped out as I would have expected. Still wondering how it held in with zero volts at the "B" terminal of the ignition switch. If it wasn't for doing voltage drop tests I probably would not had found it.

As for the starter even worn out brushes and commuter ring that worn or glazed can cause starting problems. Basically it comes down to pin pointing the problem. Just never get lock in to train of thought. Surprises do happen.