How do I unstick the intake valve of a 12HP Briggs properly? - MyTractorForum.com - The Friendliest Tractor Forum and Best Place for Tractor Information
Register Home FAQ Garage MTF Gallery Search Today's Posts Mark Forums Read Store Chat Room

Small Engines and Repair

Midwest Mower Pro

Reply
 
Thread Tools Display Modes
Old 01-11-2011, 07:27 PM   post #1 of 7
tractorpimper1989
was born to pimp tractors
 
tractorpimper1989's Avatar
 
Join Date: Jan 2009
Location: Parsons, WV (aka Tombstone)
Posts: 142
MTF Member # 21802
Images: 7
Garage
Help How do I unstick the intake valve of a 12HP Briggs properly?

Awhile back I bought a 1992 Simplicity Regent from the local lawn mower shop. I only paid $30 dollars for it because they thought the 12HP briggs engine on it was blown. before I bought it, I turned it over my hand and to surprise it had really good compression (which didn't make sense cause they said it was blown) I brought it home and started working on it. After changing the oil, checking for spark, cleaning the carb, and making sure the starter spun freely... I got the engine to start Well a couple weeks ago I started it up and shortly after that the engine stalled. When it stalled it wasn't smoking or making any weird noises, so I went to restart the engine but it didn't have any compression. well after realized that either a valve was stuck open or (worst case) one of the valve seats came out of the block. Well I finally pulled the cyl head off today (hoping for the best, but fearing the worst) and found that the intake valve was stuck wide open (no valve seat involved). So now I need to know whats the best way to loosen the valve so I can reuse this engine? BTW: there is surface rust starting to form on the valve stem but I dont know why(I stored the engine indoors in a cool dry place with no gas in the carb)
__________________
"Life should not be a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming... WOW... What a Ride!"
"There's no 'Replacement' for 'Displacement'."
Pimping tractors takes Time, Patience, and most importantly Money. Unfortunately, I only have Time...
tractorpimper1989 is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 01-11-2011, 07:58 PM   post #2 of 7
Onan18
2000 Posts and climbing!!!
 
Onan18's Avatar
 
Join Date: Mar 2010
Location: Georgia
Posts: 2,188
MTF Member # 40653
Default Re: How do I unstick the intake valve of a 12HP Briggs properly?

If I were you I would pull the valve spring cover, located on the side of the engine behind the carb in your case i think, compress the valve springs, remove the keepers, and pull both valves. Clean them really good, first with a wire brush, then with emery paper, clean the seats, run a brush through the guide to make sure it is clean and free of contaminants, lap the valves in and then check for proper clearance, grinding the stems if necessary. Re-assemble everything and you should be good to go! NOTE: After lapping the valves make sure you THOROUGHLY clean ALL of the lapping doap off of the engine and all parts. A TINY amount can really ruin your day!

Joe
Onan18 is online now   Reply With Quote Quick reply to this message
Old 01-12-2011, 01:19 PM   post #3 of 7
rayjay
2000 Posts and climbing!!!
 
Join Date: Nov 2010
Location: Buford, Ga
Posts: 2,304
MTF Member # 53093
Default Re: How do I unstick the intake valve of a 12HP Briggs properly?

Both of the intakes on my Craigslist Simplicity were stuck open from tiny rust spots. I removed the intake to discover this. I then sprayed some oily penetrating oil in the ports and tapped the rockers with a plastic mallet and the valves freed up. B&S must have used non-plated ferrous material for the valve stems and possibly the guides.
rayjay is online now   Reply With Quote Quick reply to this message
Old 01-12-2011, 01:54 PM   post #4 of 7
Fcubman
3K Poster!!!!
 
Fcubman's Avatar
 
Join Date: Oct 2008
Location: CT
Posts: 3,701
MTF Member # 18953
Images: 5
Default Re: How do I unstick the intake valve of a 12HP Briggs properly?

If they had rust on them, they weren't getting oil on them. Could be from sitting a long time, but cleaning the stems and guides should allow the normal tad of oil to get on the stems.

Anecdote:
I had a small Briggs that someone stored on its side. The entire gas tank contents seems to have run down the carb and onto the intake stem. The valve was stuck open, and it took the better part of a day with penetrating oil and gentle persuasion to free it up. It now runs like new. It's a good running little motor, but made so cheaply I'm surprised it runs! It's on a small Sears rototiller. It does get the job done, and I only use it less than 2 hours a year. It should last a while at that rate.
__________________
Remember, I'm pullin' for ya! We're all in this together!
(Red Green)

Living in The Land Of The Free - because of The Brave!
Fcubman is offline   Reply With Quote Quick reply to this message
Old 01-12-2011, 03:26 PM   post #5 of 7
bstrucker
Proud Member of the 1K Club
 
bstrucker's Avatar
 
Join Date: Oct 2008
Location: Pa
Posts: 1,209
MTF Member # 18659
Default Re: How do I unstick the intake valve of a 12HP Briggs properly?

Put some penetrating oil in the intake port and let it sit for a day,then take a brass or plastic hammer and try to tap it shut,just make sure that your hitting it dead center or you can bend the valve.I've used a block of aluminum held against the valve also or a wood block,that way it's easier to keep that centered.Rust could be your problem but I've had engines where the intake stuck open from a varnish deposit on the stem,eitherway the penetrating oil will help free it.Once you get it closed,then you can take the keeper off and pull it out to see how bad the rust is and get it cleaned off.
bstrucker is online now   Reply With Quote Quick reply to this message
Old 01-12-2011, 06:13 PM   post #6 of 7
Fcubman
3K Poster!!!!
 
Fcubman's Avatar
 
Join Date: Oct 2008
Location: CT
Posts: 3,701
MTF Member # 18953
Images: 5
Default Re: How do I unstick the intake valve of a 12HP Briggs properly?

Agreed, and perhaps the varnish just looks like rust. Sometimes it has a reddish tinge, and can fool the eye.
__________________
Remember, I'm pullin' for ya! We're all in this together!
(Red Green)

Living in The Land Of The Free - because of The Brave!
Fcubman is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 01-12-2011, 07:34 PM   post #7 of 7
rayjay
2000 Posts and climbing!!!
 
Join Date: Nov 2010
Location: Buford, Ga
Posts: 2,304
MTF Member # 53093
Default Re: How do I unstick the intake valve of a 12HP Briggs properly?

It's rust. If you tap on the head of the valve you are just jamming it worse.
rayjay is online now   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the MyTractorForum.com - The Friendliest Tractor Forum and Best Place for Tractor Information forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:53 PM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.
Compact Tractor Reviews Tractor Reviews Snowblowers Lawn Mower Forum
My Tractor Forum Snow Thrower Power Equipment Forum
Combine Forum Snowblower Forum ATV and UTV Reviews