rebuilding 17.5 B&S - 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 04-25-2012, 12:11 PM   post #1 of 23
speedybmc
MTF Junior Poster
 
speedybmc's Avatar
 
Join Date: Apr 2012
Location: Mississippi
Posts: 28
MTF Member # 72620
Default rebuilding 17.5 B&S

I was given an craftsman mower with a 17.5hp single cylinder briggs and stratton. When i got the mower (last year) the engine was smoking a little. I ran it until now always checking the oil and adding if needed. Well this year it is a little worse and i want to overhaul it. I removed it from the mower and started tearing it down. I took the valves out and removed the old valve seal. Now, i don't know anything about a small engine but are the valves supposed to have slight play in them from side to side? With me holding the valves in and open just slightly i can wiggle them. Its not much but there is slight play in them. In other words they are not tight with in the valve guide. If this is ok and doesn't cause any problems i wont worry with it and continue the build.

What do i need to do to get the carbon build up from off the piston and around the valves/combustion chamber? I've heard things from oven cleaner to a wire brush. i don't want to do anything that'll hurt it.

I have not got to the bottom end yet so there may be more question on the way.
Thanks for all of your help
speedybmc is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 04-25-2012, 03:47 PM   post #2 of 23
RED-85-Z51
Certified Technician
 
RED-85-Z51's Avatar
 
Join Date: Jul 2006
Location: Florida
Posts: 8,312
MTF Member # 2950
Images: 7
Default Re: rebuilding 17.5 B&S

I dont have the specs in front of me, but the valves shouldnt be sloppy in the guides.

I take some oil, and lube the stems, stick them in the guides until they are flush with the top of the guide, and seal off the other end with my finger, and pull the valve out...it should make a little suction as you pull it out.
__________________
1993 Wheel Horse 416-H
Onan P216G

1962 WH702

1997 K3500 Dually Sierra
Crew Cab, Long bed, Vortec 454

1995 K3500 Silverado
TBI 454

1995 K2500 Silverado
6.5 Detroit Turbo Diesel

1994 GMC Sierra Z71
350 TBI

RED-85-Z51 is offline   Reply With Quote Quick reply to this message
Old 04-25-2012, 03:59 PM   post #3 of 23
speedybmc
MTF Junior Poster
 
speedybmc's Avatar
 
Join Date: Apr 2012
Location: Mississippi
Posts: 28
MTF Member # 72620
Default Re: rebuilding 17.5 B&S

Ok i have the head with me so i'll go try that out now. Thanks

EDIT:There is a little suction when i pull it. Not alot but enough to tell it has some.

Last edited by speedybmc; 04-25-2012 at 04:09 PM.
speedybmc is offline   Reply With Quote Quick reply to this message
Old 04-25-2012, 06:36 PM   post #4 of 23
Walt 2002
Senior MTF Poster
 
Join Date: Jan 2006
Location: IL
Posts: 11,259
MTF Member # 1229
Default Re: rebuilding 17.5 B&S

I have a Service Manual for your engine IF you would like a PDF copy. Address below, put in proper format and remind me, model number of engine and what you want. I think you will find that B&S has a go-no go Gage to check the valve guide but no specs. and the fix is a new head.

Walt Conner
wconner5 at fronter dot com
Walt 2002 is offline   Reply With Quote Quick reply to this message
Old 04-25-2012, 07:27 PM   post #5 of 23
RED-85-Z51
Certified Technician
 
RED-85-Z51's Avatar
 
Join Date: Jul 2006
Location: Florida
Posts: 8,312
MTF Member # 2950
Images: 7
Default Re: rebuilding 17.5 B&S

I think Ive seen that gauge before Walt, I think its tapered with markings on it, and there is a line that if it is at or past that line, its too big, replace the head, or ream/replace the guide.

If its got some suction, its probably not an immediate problem, ive pulled apart high hours engines with the valves wobbling all over, but ran fine, no smoke or problems....but the guides were completely shot to **** and back. Eventually, if it gets bad enough, the valve wont seat and it will burn.
__________________
1993 Wheel Horse 416-H
Onan P216G

1962 WH702

1997 K3500 Dually Sierra
Crew Cab, Long bed, Vortec 454

1995 K3500 Silverado
TBI 454

1995 K2500 Silverado
6.5 Detroit Turbo Diesel

1994 GMC Sierra Z71
350 TBI

RED-85-Z51 is offline   Reply With Quote Quick reply to this message
Old 04-25-2012, 11:19 PM   post #6 of 23
Walt 2002
Senior MTF Poster
 
Join Date: Jan 2006
Location: IL
Posts: 11,259
MTF Member # 1229
Default Re: rebuilding 17.5 B&S

I don't worry about a little play and seldom replace valve guides. I do not believe valve guides are available for this engine, I think B&S says not replaceable.

Walt Conner
Walt 2002 is offline   Reply With Quote Quick reply to this message
Old 04-25-2012, 11:39 PM   post #7 of 23
speedybmc
MTF Junior Poster
 
speedybmc's Avatar
 
Join Date: Apr 2012
Location: Mississippi
Posts: 28
MTF Member # 72620
Default Re: rebuilding 17.5 B&S

Hmm thanks guys. i think I'm going to run it like they are and start saving up to get a head and valves.

Another question. Is there a way to get a little more hp out of these little engine? Like maybe porting the intake and exhaust port. A few guys i work with was wanting to do it for me and i noticed there is a slight lip of excess cast around the inside diameter of the intake port. Would porting it hurt it more than help? They just put the bug in my ear and i was curious if i could gain a little more horses out of it while i had it tore down waiting on parts.
speedybmc is offline   Reply With Quote Quick reply to this message
Old 04-25-2012, 11:44 PM   post #8 of 23
speedybmc
MTF Junior Poster
 
speedybmc's Avatar
 
Join Date: Apr 2012
Location: Mississippi
Posts: 28
MTF Member # 72620
Default Re: rebuilding 17.5 B&S

Quote:
Originally Posted by Walt 2002 View Post
I don't worry about a little play and seldom replace valve guides. I do not believe valve guides are available for this engine, I think B&S says not replaceable.

Walt Conner
Yeah they're not available. They just offer the head and valves.
speedybmc is offline   Reply With Quote Quick reply to this message
Old 04-26-2012, 12:00 AM   post #9 of 23
Onan18
2000 Posts and climbing!!!
 
Onan18's Avatar
 
Join Date: Mar 2010
Location: Georgia
Posts: 2,248
MTF Member # 40653
Default Re: rebuilding 17.5 B&S

BUT, a GOOD machine shop can make a set and shoulder them so they won't pull out of the head, a common problem on this series engine. I believe my machinist took a set for a Perkins and turned them down then reamed the inside and installed a liner to bring it into spec.

Joe
Onan18 is online now   Reply With Quote Quick reply to this message
Old 04-26-2012, 12:32 AM   post #10 of 23
RED-85-Z51
Certified Technician
 
RED-85-Z51's Avatar
 
Join Date: Jul 2006
Location: Florida
Posts: 8,312
MTF Member # 2950
Images: 7
Default Re: rebuilding 17.5 B&S

Porting really helps to allow more flow at high rpms..but these are governed engines. At full speed no load, the carb is only opening about 10% tops...and even under 100% load, the engine speed doesnt exceed 3600rpms...so porting really would not help much if anything, as the engine cant demand more air.

If it were an ungoverned engine, on a racing mower that was going to be turned up to 5000, 6000 rpms...and it was built to handle it, Port away and put in bigger valves, roller rockers, slapper cam, etc...haha
__________________
1993 Wheel Horse 416-H
Onan P216G

1962 WH702

1997 K3500 Dually Sierra
Crew Cab, Long bed, Vortec 454

1995 K3500 Silverado
TBI 454

1995 K2500 Silverado
6.5 Detroit Turbo Diesel

1994 GMC Sierra Z71
350 TBI

RED-85-Z51 is offline   Reply With Quote Quick reply to this message
Old 04-26-2012, 12:38 AM   post #11 of 23
speedybmc
MTF Junior Poster
 
speedybmc's Avatar
 
Join Date: Apr 2012
Location: Mississippi
Posts: 28
MTF Member # 72620
Default Re: rebuilding 17.5 B&S

Quote:
Originally Posted by RED-85-Z51 View Post
Porting really helps to allow more flow at high rpms..but these are governed engines. At full speed no load, the carb is only opening about 10% tops...and even under 100% load, the engine speed doesnt exceed 3600rpms...so porting really would not help much if anything, as the engine cant demand more air.

If it were an ungoverned engine, on a racing mower that was going to be turned up to 5000, 6000 rpms...and it was built to handle it, Port away and put in bigger valves, roller rockers, slapper cam, etc...haha
I see. Well i wont be doing any racing anytime soon (not on my mower anyway haha) so i'll keep it the way it is. Thank you all for all of your information.
speedybmc is offline   Reply With Quote Quick reply to this message
Old 04-26-2012, 07:17 AM   post #12 of 23
daytona54
Senior MTF Member
 
daytona54's Avatar
 
Join Date: Mar 2009
Location: fl.
Posts: 187
MTF Member # 22907
Default Re: rebuilding 17.5 B&S

might want to hone your cylinder and replace the rings speedybmc if your going that deep into the engine ( worn rings will make your engine smoke ) and connecting rod bearings as there not costly..........how bout some pic's of your rebuild,We love them here............
daytona54 is offline   Reply With Quote Quick reply to this message
Old 04-26-2012, 08:52 AM   post #13 of 23
Walt 2002
Senior MTF Poster
 
Join Date: Jan 2006
Location: IL
Posts: 11,259
MTF Member # 1229
Default Re: rebuilding 17.5 B&S

" and connecting rod bearings "

Well that would be the entire connecting rod as there are no "bearings". $30 - $35.

Walt Conner
Walt 2002 is offline   Reply With Quote Quick reply to this message
Old 04-26-2012, 05:21 PM   post #14 of 23
speedybmc
MTF Junior Poster
 
speedybmc's Avatar
 
Join Date: Apr 2012
Location: Mississippi
Posts: 28
MTF Member # 72620
Default Re: rebuilding 17.5 B&S

There were no bearings on the rod. But it was in good shape along with the rings. The culprit causing the smoke was a blown head gasket and possible the valves. it was sucking oil from the push rod valley. Everything else except the valves was in good shape.
speedybmc is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 04-26-2012, 06:36 PM   post #15 of 23
daytona54
Senior MTF Member
 
daytona54's Avatar
 
Join Date: Mar 2009
Location: fl.
Posts: 187
MTF Member # 22907
Default Re: rebuilding 17.5 B&S

My bad about the 'connecting rod bearings' sorry to mis-inform you
hope the re-build go's well....
Daytona
daytona54 is offline   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 10:53 AM.



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