25cc Piston Installation - 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 07-05-2012, 02:11 PM   post #1 of 9
Dave M
Senior MTF Member
 
Join Date: May 2008
Location: OH
Posts: 159
MTF Member # 12053
Default 25cc Piston Installation

I'm replacing a piston in a leaf blower and the new piston is marked with a black dot (and also a dimple) which kinda tells me it wants to go in one way, mark toward the flywheel or mark away from the flywheel. Sorry, I didn't note the way it came out. Anybody know which way it installs, or if it matters. Thanks for your help.
Dave M is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 07-05-2012, 06:07 PM   post #2 of 9
RED-85-Z51
Certified Technician
 
RED-85-Z51's Avatar
 
Join Date: Jul 2006
Location: Florida
Posts: 8,258
MTF Member # 2950
Images: 7
Default Re: 25cc Piston Installation

Whats it off of?

And it definitely matters. Piston rings on 2 strokes are pinned in so they can spin, so the piston needs to assemble in such a way that the end gaps do not catch either of the ports.

Generally, a mark would coincide with the exhaust port on the head. Or with the flywheel side of the engine, but not all.
__________________
1993 Wheel Horse 416-H
Onan P216G

1962 WH702

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 07-05-2012, 06:23 PM   post #3 of 9
Dave M
Senior MTF Member
 
Join Date: May 2008
Location: OH
Posts: 159
MTF Member # 12053
Default Re: 25cc Piston Installation

Thank you for the response; This is a Poulan Pro BMV200VS leaf blower. Piston # is 545081864 which I think might be used on Weedeater and/or Craftsman brands with a 25cc motors. There is also a a small arrowhead stamped on the bottom of the piston on the wrist pin casting, pointing away from the connecting rod. The ring is indeed pinned and also has a white marking on it that I can view through the intake or exhaust port, depending on which way I install the piston. Does that help to determine the way the piston installs? Did you mean to say that the ring is pinned so it can't spin? Thank you again for your wisdom.

Last edited by Dave M; 07-05-2012 at 06:44 PM.
Dave M is offline   Reply With Quote Quick reply to this message
Old 07-05-2012, 06:53 PM   post #4 of 9
markusedma
Senior MTF Member
 
Join Date: Aug 2009
Location: Waterloo Ontario Canada
Posts: 526
MTF Member # 30825
Default Re: 25cc Piston Installation

Just look to see which way the ring ends wont be at one of the ports.
__________________
3x Honda 4514, 2x Honda HT3813
2X JD L130, LX178
Roper YT16 Hydro,
Kubota G4200hst
Kubota B7100D
2X Kubota G5200HST
Cub Cadet 2518
Sears craftsman DGT6000
markusedma is offline   Reply With Quote Quick reply to this message
Old 07-05-2012, 08:27 PM   post #5 of 9
RED-85-Z51
Certified Technician
 
RED-85-Z51's Avatar
 
Join Date: Jul 2006
Location: Florida
Posts: 8,258
MTF Member # 2950
Images: 7
Default Re: 25cc Piston Installation

Right, pinned so the CANT spin, my bad.

When the white mark is viewed from the exhaust port, where is the mark on the top of thep iston?
__________________
1993 Wheel Horse 416-H
Onan P216G

1962 WH702

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 07-05-2012, 10:03 PM   post #6 of 9
Dave M
Senior MTF Member
 
Join Date: May 2008
Location: OH
Posts: 159
MTF Member # 12053
Default Re: 25cc Piston Installation

When the white mark on the ring is viewed in the exhaust port, the dimple on the piston and the black (paint) mark on the top of the piston are facing the flywheel. That's the way I put it together, but I haven't tried to fire it up yet.
Dave M is offline   Reply With Quote Quick reply to this message
Old 07-12-2012, 10:41 PM   post #7 of 9
Dave M
Senior MTF Member
 
Join Date: May 2008
Location: OH
Posts: 159
MTF Member # 12053
Default Re: 25cc Piston Installation

I didn't hear from anybody, so I thought I must have assembled this piston correctly in the motor. Fired it up and after it warmed, seemed to run okay. Fired it up today, and, not so good. Sounds like something ain't right, like a busted ring. It'll be a week before I can tear it back down, just to see what went wrong, but if I had to guess, I'd say I installed the piston backwards. Totally my fault for not noting the way the original piston came out. But, for sure, I'm not redoing this project. Shoulda just bought a new blower at the git-go. Education is a wonderful, albeit at times, an expensive thing.
Dave M is offline   Reply With Quote Quick reply to this message
Old 07-13-2012, 02:41 AM   post #8 of 9
RED-85-Z51
Certified Technician
 
RED-85-Z51's Avatar
 
Join Date: Jul 2006
Location: Florida
Posts: 8,258
MTF Member # 2950
Images: 7
Default Re: 25cc Piston Installation

it should be right, its how I would have assembled it, if I wasnt the one that disassembled it.

If there were a problem, id think you would have known there was a problem the first time it turned over.

Does it still have compression?
__________________
1993 Wheel Horse 416-H
Onan P216G

1962 WH702

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
Sponsored Links
Advertisement
 
Old 07-13-2012, 09:35 PM   post #9 of 9
Dave M
Senior MTF Member
 
Join Date: May 2008
Location: OH
Posts: 159
MTF Member # 12053
Default Re: 25cc Piston Installation

Thank you, Red. I appreciate you staying with me on this motor, but it's not like I did this to the Onan in the 316, or the Kohler Magnum in the Horse. Anyway, I'm away for a week, so until I get home, I won't know if has compression or what the issue might be. I'll definitely tear it back down just to see what's what. I'm just not gonna throw any more dough at it, that's all. I know you are the guru here, and I've seen a lot of guys give you well deserved accolades. You have my respect as well. Thank you again for taking time to respond and for your help.
Dave M 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:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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 12:20 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