Notices
Engine Conversions Discuss all aspects of engine conversions in this forum

Homelite 25cc conversion

Old 06-27-2009, 02:28 AM
  #1  
Timthetoolman1
Senior Member
Thread Starter
My Feedback: (6)
 
Timthetoolman1's Avatar
 
Join Date: May 2004
Location: Fort Worth, TX
Posts: 977
Likes: 0
Received 0 Likes on 0 Posts
Default Homelite 25cc conversion

I have two blowers with Homelite 25cc. One is just pumping out smoke so I'm taking it apart tomorrow.
I want to put it in a 1/5th scale clipped wing Cub. Maybe some floats too.
I want the electronic ignition. I have access to a lathe (a very accurate lathe! and CNC mill so just about anything I can draw can be made) so I may make my own hub.
I might have to put in a new ring. I've read av8tor talk about a special piston/pin/ring set.
Here are my questions.
Where do I get an electronic ignition. I saw one at my hobby shop today. for about $80? and about $165? for the one with the hub from CH. Are there better deals out there.

Should I get the upgraded rings/piston/pin setup and where are these found.

Should I use the Walbro 10?

What kind of magnet goes in the hub?

Would it be cheaper to buy a new Zenoah EI than upgrade one of these engines? I have a Saito 1.20 but I prefer gas.


Thanks in advance, Tim
Old 06-27-2009, 07:12 AM
  #2  
w8ye
My Feedback: (16)
 
w8ye's Avatar
 
Join Date: Dec 2001
Location: Shelby, OH
Posts: 37,567
Likes: 0
Received 1 Like on 1 Post
Default RE: Homelite 25cc conversion


ORIGINAL: rangerman

I have two blowers with Homelite 25cc. On is just pumping out smoke so I'm taking it apart tomorrow.
I want to put it in a 1/5th scale clipped wing Cub. Maybe some floats too.
I want the electronic ignition. I have access to a lathe (a very accurate lathe! and CNC mill so just about anything I can draw can be made) so I may make my own hub.
I might have to put in a new ring. I've read av8tor talk about a special piston/pin/ring set.
Here are my questions.
Where do I get an electronic ignition. I saw one at my hobby shop today. for about $80? and about $165? for the one with the hub from CH. Are there better deals out there.

Should I get the upgraded rings/piston/pin setup and where are these found.

Should I use the Walbro 10?

What kind of magnet goes in the hub?

Would it be cheaper to buy a new Zenoah EI than upgrade one of these engines? I have a Saito 1.20 but I prefer gas.


Thanks in advance, Tim
http://www.ch-ignitions.com/

Frank Bowman

1211 N Allen Ave. Farmington, N.M. 87401-3568

505-327-0696 Email: ringmaster46@msn.com

Use a Walbro WA-167 or WT-499
Old 06-27-2009, 09:13 AM
  #3  
rangerfredbob
Senior Member
My Feedback: (13)
 
Join Date: Jul 2005
Location: Salem, OR
Posts: 1,686
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Homelite 25cc conversion

THIS is your best bet ignition wise, it has everything you would need other than the prop hub and a battery.

I used pretty much the same thing on my Mac 32cc engine and it runs good, I would suggest making a hub with a taper in the back and a ring with setscrew for the magnet, it makes for an easy to set up system, looks clean too. For these small engines you don't have to make anything too complicated, they seem to hold the prop fine with just a machined surface, no need to knurl (if you have the tools, go for it, never hurts). for a prop hub, the crank threads are 5/16-24 and I would suggest going 5/16-18 for the prop bolt, easier to find bolts and a little more meat in the threads.

the attached picture is of my mac 32 that I converted to EI to give you an idea of what I did, the homie should convert about the same just with more cutting of the crankcase.

just wanted to note that the ignition I linked to above you would want to specify one of the 14mm spark plug units, it doesn't matter if it's taper or gasket seat these are set up to work with either... when I got my ignition I ended up with the 10mm plug and had to make an adapter (an old spark plug, my lathe and a tap made fine work of it)
Attached Thumbnails Click image for larger version

Name:	Rp44801.jpg
Views:	101
Size:	51.2 KB
ID:	1225580  
Old 06-27-2009, 09:18 AM
  #4  
w8ye
My Feedback: (16)
 
w8ye's Avatar
 
Join Date: Dec 2001
Location: Shelby, OH
Posts: 37,567
Likes: 0
Received 1 Like on 1 Post
Default RE: Homelite 25cc conversion

Most long shaft engines are 3/8"
Old 06-27-2009, 09:19 AM
  #5  
rangerfredbob
Senior Member
My Feedback: (13)
 
Join Date: Jul 2005
Location: Salem, OR
Posts: 1,686
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Homelite 25cc conversion

good call, I haven't taken apart my homie blower yet, or one of my clutched homie's... I do know that the 7/16" threads on that Mac engine seem monsterous in comparison to the 5/16" or 8mm engines...
Old 06-27-2009, 09:48 AM
  #6  
w8ye
My Feedback: (16)
 
w8ye's Avatar
 
Join Date: Dec 2001
Location: Shelby, OH
Posts: 37,567
Likes: 0
Received 1 Like on 1 Post
Default RE: Homelite 25cc conversion

Some blowers are left hand rotation and present a problem as a model engine

If you study the blower before you take it apart, you can determine this by looking at the pull start
Old 06-27-2009, 12:29 PM
  #7  
Timthetoolman1
Senior Member
Thread Starter
My Feedback: (6)
 
Timthetoolman1's Avatar
 
Join Date: May 2004
Location: Fort Worth, TX
Posts: 977
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Homelite 25cc conversion

Thanks guys.
Where's a source for Walbro, or should I use the stock carb?
Old 06-27-2009, 01:49 PM
  #8  
w8ye
My Feedback: (16)
 
w8ye's Avatar
 
Join Date: Dec 2001
Location: Shelby, OH
Posts: 37,567
Likes: 0
Received 1 Like on 1 Post
Default RE: Homelite 25cc conversion

You very much need a larger carb in the 11mm range.

Look on the internet for them?

You need both low speed and high speed mixture screws for airplane use

Old 06-27-2009, 02:30 PM
  #9  
Timthetoolman1
Senior Member
Thread Starter
My Feedback: (6)
 
Timthetoolman1's Avatar
 
Join Date: May 2004
Location: Fort Worth, TX
Posts: 977
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Homelite 25cc conversion

Thanks, where do you get them?
Old 06-27-2009, 03:50 PM
  #10  
w8ye
My Feedback: (16)
 
w8ye's Avatar
 
Join Date: Dec 2001
Location: Shelby, OH
Posts: 37,567
Likes: 0
Received 1 Like on 1 Post
Default RE: Homelite 25cc conversion

I've bought four carbs from these guys but there are many other places to get them. http://www.outdoordistributors.com/

http://www.davesmotors.com/s.nl/c.88...t.A/id.4131/.f

Old 06-28-2009, 12:51 PM
  #11  
Timthetoolman1
Senior Member
Thread Starter
My Feedback: (6)
 
Timthetoolman1's Avatar
 
Join Date: May 2004
Location: Fort Worth, TX
Posts: 977
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Homelite 25cc conversion

Ok, I've read about the numbering system and I think it's a WT carb. But what is a Walbro 32 and what about the HDA HD carbs?
Thanks, Tim
Old 06-28-2009, 01:01 PM
  #12  
w8ye
My Feedback: (16)
 
w8ye's Avatar
 
Join Date: Dec 2001
Location: Shelby, OH
Posts: 37,567
Likes: 0
Received 1 Like on 1 Post
Default RE: Homelite 25cc conversion

The little number cast into the venturi? A 32 would be a carb with a 1/2" diameter venturi

You need to look for a Walbro carb with a "27" or "28" in the venturi for a Homelite 25. it could be a WA or WT carb

The HD and HDA carbs are bigger engines

Old 06-28-2009, 03:07 PM
  #13  
Timthetoolman1
Senior Member
Thread Starter
My Feedback: (6)
 
Timthetoolman1's Avatar
 
Join Date: May 2004
Location: Fort Worth, TX
Posts: 977
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Homelite 25cc conversion

Ok, how do you know if you need a 433, 499, 755, or what ever? Is there a chart somewhere that lists venturi sizes with the model numbers?
Why aren't there stickys in this forum with that info? You guys are a WEALTH of knowledge. My flying buddies were over last night and we're all clueless (and that's saying something for these guys who build UAV's and have been in the hobby a long time).

Thanks, Tim
Old 06-28-2009, 03:29 PM
  #14  
w8ye
My Feedback: (16)
 
w8ye's Avatar
 
Join Date: Dec 2001
Location: Shelby, OH
Posts: 37,567
Likes: 0
Received 1 Like on 1 Post
Default RE: Homelite 25cc conversion

http://www.prestwich.ndirect.co.uk/walbrocarbs.htm
Old 07-02-2009, 10:52 PM
  #15  
Timthetoolman1
Senior Member
Thread Starter
My Feedback: (6)
 
Timthetoolman1's Avatar
 
Join Date: May 2004
Location: Fort Worth, TX
Posts: 977
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Homelite 25cc conversion

Here's the plane I'm wanting to put it in. I may have to move the servos to the back.

Attached Thumbnails Click image for larger version

Name:	Sq47206.jpg
Views:	77
Size:	52.2 KB
ID:	1228902  
Old 07-02-2009, 10:55 PM
  #16  
Timthetoolman1
Senior Member
Thread Starter
My Feedback: (6)
 
Timthetoolman1's Avatar
 
Join Date: May 2004
Location: Fort Worth, TX
Posts: 977
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Homelite 25cc conversion

Here's some photos of a Ryobi I found. I think av8tor was saying this Ryobi isn't the most powerful of the 31 cc engines, maybe someone can say if it is or isn't (because of the bar in the exhaust?). The trimmer that it's on runs poorly and smokes a lot. Do you think the rings are bad? Here's some photos of the cylinder wall too.
The Homelite 25cc engines I have might be better for this size plane. One of those starts fine, acts like it needs a carb rebuild, and the other one smokes like a train. I'll try to get some photos of the one I choose this weekend.
Attached Thumbnails Click image for larger version

Name:	Ca80628.jpg
Views:	57
Size:	35.9 KB
ID:	1228904   Click image for larger version

Name:	Hc92847.jpg
Views:	67
Size:	50.5 KB
ID:	1228905   Click image for larger version

Name:	In25933.jpg
Views:	84
Size:	41.4 KB
ID:	1228906   Click image for larger version

Name:	Fz73021.jpg
Views:	54
Size:	31.3 KB
ID:	1228907   Click image for larger version

Name:	Te48098.jpg
Views:	65
Size:	20.1 KB
ID:	1228908  
Old 07-02-2009, 11:34 PM
  #17  
Timthetoolman1
Senior Member
Thread Starter
My Feedback: (6)
 
Timthetoolman1's Avatar
 
Join Date: May 2004
Location: Fort Worth, TX
Posts: 977
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Homelite 25cc conversion

I noticed my Homelites have a metal plate on the front of the engine. Can this be milled off? At least the exhaust on them are on the side and not the back like the Ryobi.
Old 07-02-2009, 11:42 PM
  #18  
w8ye
My Feedback: (16)
 
w8ye's Avatar
 
Join Date: Dec 2001
Location: Shelby, OH
Posts: 37,567
Likes: 0
Received 1 Like on 1 Post
Default RE: Homelite 25cc conversion

Yes

I did a couple and I sawed them off on a big band saw and finished up with a big half round file rasp
Old 07-03-2009, 12:07 PM
  #19  
rangerfredbob
Senior Member
My Feedback: (13)
 
Join Date: Jul 2005
Location: Salem, OR
Posts: 1,686
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Homelite 25cc conversion

if you are using electronic ignition the whole plate can come off, it doesn't take long with a hack saw, the trick is to make a couple cuts down the side and just break off big pieces with pliers. I wouldn't go all out removing aluminum as all of that on the front is probably 2-3 ounces tops.

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.