Export thread

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

#1

bugdewde

bugdewde

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?


#2

bugdewde

bugdewde

20200706_183112.jpg


#3

S

slomo

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


#4

bugdewde

bugdewde

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!


#5

Scrubcadet10

Scrubcadet10



#6

T

Tinkerer200

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


#7

bugdewde

bugdewde

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.


#8

T

Tinkerer200

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


#9

bugdewde

bugdewde

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 ?


#10

S

slomo

If available, buy a new head for it.

slomo


#11

Scrubcadet10

Scrubcadet10

If available, buy a new head for it.

slomo


#12

bugdewde

bugdewde

If available, buy a new head for it.

slomo

It's a flathead. The valve is in the block.


#13

I

ILENGINE

Had one like that years ago. Put JB weld around the seat area to use as space filler and then inserted the seat and let the valve pressure hold it in place until the JB cured, and then staked the seat in place.


#14

S

slomo

It's a flathead. The valve is in the block.
Copy that, I saw Scrubcadet10's post and saw a different engine type with the head off. No doubt L-heads are not removable.

slomo


#15

bugdewde

bugdewde

Runs good as long as it doesn't shut off. Once you shut it off, the seat falls out. Lol
Running on 1 cylinder:


Top