B&S 17.5 hp opppsed twin valve seat???

bugdewde

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So I bought this mower with a dead cylinder. I pulled the offending flathead to find the valve seat had come loose.

See video ...

Is there an easy procedure to fix this? What am I looking at?
 

slomo

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Clean the pocket where the valve seat rests. Gently hammer valve seat back into the head with a proper fitting socket. Then you have to use a punch to push metal towards the valve seat ,all the way around the seat. Called restaking the seat I think. Should be several videos on youtube about it.

Likely cause is the cylinder was overheated. Most people do not take the starter/blower/flywheel cover off and clean the cylinder block cooling fins. Engine could have a lot of oil, dirt, grass and bugs that clog the cooling fins. It's in the engine manual to check like yearly. Normally happens on the exhaust side as it runs hotter than the intake valve.

slomo
 

bugdewde

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Thanks, slomo.
I was hoping there was an easy fix that didn't require disassembly.
I bought it for the good condition deck, but the rest of the mower appears to be good.
It needs to be mowing!
 

Tinkerer200

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The staking procedure works if done properly and the block isn't wallowed out. I can send you a Service Manual showing the proper procedure, head bolt torque, etc. Address below IF you want it, Put in proper format and remind me the engine model number and what you want.
Walt Conner
wconner5 at frontier dot com
 

bugdewde

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Thanks guys .....
It was very loose. The block was pretty worn. I attempted the staking method but it fell back out within 3 or 4 revolutions.
Looks like I'll be swapping in the other engine I have.

..... I think the engine I'm hoping to swap in has a different pulley mounting setup. Keyway vs bolt ... guess I better look it over good when I get a chance.
 

Tinkerer200

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If you know a machinest, he might make you an oversize valve seat. I expect there are valve seats available which would work but I never bothered to look for them.
Walt Conner
 

bugdewde

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I do have a friend that is a machinist .... he mentioned the oversized seat thing .... but then said .... "but at that point you usually just junk it."
Damn!!!

A coworker suggested using JB Weld to hold the seat in ......

If I attempt this .... as a last resort .... how can I press the valve into the seat tightly while it cures overnight?

I've never taken one of these opposed twins apart .... is there a valve access panel? Maybe remove the valve to get the seat in better?

Anyone done the JB Weld thing? I mean, engine seems to be unusable except for parts at this point. Might be worth a shot ?
 
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