Hey all,



Cliff Notes: I have a Homelite 25 cc ST-175 trimmer motor, on which I broke the piston ring, and as such, need a new one, but have no places nearby who sell HomeLite parts, and want to find a place which can sell me the ring at a reasonable price.



I'm not actually in to building model RC planes, or otherwise, however, I have found this site to be most informative as far as the HomeLite 25 and 30cc motors go.

Where I live, in Ottawa, Canada, unfortunately, I have called around, and everyone seems to have something against HomeLite, and does not carry any parts for HomeLite products anymore.

I'm mounting this motor to a scooter (one of the kind with 10" air-filled tires), and before doing so, I had the good idea of tearing down the motor. There was lots of carbon build-up in it, and in my opinion, it definately needed cleaning.

I'm not too experienced with 2-stroke motors, although I currently have a Weed-Eater Featherlite motor on my scooter (which I've torn down twice), however, it is wearing out quickly.

I thought the Homelite ST-175 string trimmer (25 cc I believe) motor would be appropriate for my application, and have heard good things about this motor from these forums I believe. It is the model with a bridge running vertical in the head where the exhaust port is, which as far as I am aware, denotes that it is a 25cc model.

My problem is that when tearing down the HomeLite 25cc motor, I broke the piston ring. This essentially renders the motor useless to me, as there appears to be no support for the motor in my city.

I was wondering if anyone would be able to let me know of any shops which I would be able to get the piston rings from (I would presume they wouldn't be too expensive), or, if I'm replacing that, if there were any suitable aftermarket parts which would allow me to extract more power out of the motor, and the websites or locations where I could get in touch with someone who could get me the piston ring, or, I've heard of there being a dual-ring piston being available, and if that would work without problems, I would even consider opting for that, if it wasn't much more expensive.

Lastly, I was wondering what are indicators you should be checking your piston ring. On the motor, when I tore it down, there was (and still is) carbon buildup slightly on the side walls of the piston (although there is no scoring on the piston), and the piston ring was compressed into the piston, and wasn't movable at all -- it simply conformed to shape of the piston, which I presumed would provide me no compression. Was I correct in trying to remove it? Some of the small-engine shops in my area told me I should not have removed the head from the motor, unless I was positive there were problems.


Thanks for all your help!
Khany2002

The best rings in the country

Frank C. Bowman
1211 N Allen Ave
Farmington, NM 87401-3568
505-327-0696

[email protected]

Around $12

Enjoy,

Jim

The ring may have been stuck so tight in ring grove it would have broke no matter who tried to free it up. Most times though a good soaking in acetone or spray with some kind of penetrate will do the job of freeing the ring up. A broken ring, ground square makes a good ring grove cleaner to scrape the carbon out. Bowman rings are thr best they say. Do a search and you will find more on that. If I had a extra ring I would send it to you free. I will look into finding one for you if you do not find one yourself. Good Luck Capt,n

Thanks for the quick responses, everyone!

I will try to get in touch with Frank at the e-mail address listed above, however, I'm not sure if I need such a good quality piston ring -- stock would do, but I'll take pretty much anything as long as it will work.

Thanks for the help in looking, captinjohn, it would be great if you could find a suitable for ring for me, but if that fails, I guess I'll be opting for the "best rings in the country"! [sm=biggrin.gif]

I have ordered Homelite 25cc Parts from http://www.outdoordistributors.com/H...rts-lists.html with good success. You can search through the proper Service guides from there if you know the UT Number of your string trimmer. All of the string trimmer motors that I have cross reference to the same part number of HOM-PS01359. The stock ring will probably cost you more than ordering a ring from Frank if you consider the cost of shipping to Canada.

The indicators that you can check for are lack of power, low compression. For me I have gotten away with a visual check through the exhaust port. I usually check for heavy carbon buildup which would indicate to me that there may be a lot of carbon in the ring groove which could prevent the ring from expanding to fit the cylinder properly. I have had 5 motors with stuck rings of the 12 that I have tinkered with. I usually put everything (Cylinder and piston) in a crock pot antifreeze bath over night to loosen up the carbon and clean everything up. I ended up having to break the ring on 2 of the 5 motors even after the antifreeze bath to get the rings out of them. Make sure that you are using the proper gas/oil mix so that the engine does not carbon up again.

Frank's rings, in most cases, are cheaper than the stock original replacement rings,

Enjoy,

Jim

I think they only sell the ring with the piston and conrod, which makes it pricey. I could be wrong though.

Thanks, again, for the replies!

I'd be happy if Frank could provide me with a ring for this motor, as that seems to be all that is the problem with it, otherwise, the motor would run perfectly (I have never tried running it myself, but I've heard it ran well).

I was wondering what I could get by means of gasket material for this motor as well, as I noticed that the gasket between the head and the block was broken, as well as the gasket from the exhaust port to muffler was broken. I have some rubber-fiber gasket material sheets, suitable for fuel pump mountings, but won't break down with oil, coolant, or gasoline, rubber-cellulose suitable for water outlets (suitable for water and coolant), and cork-rubber sheets, which won't break down in oil, coolant, or gasoline.

Making my own gaskets seems to be the easiest and cheapest route for me, as getting new ones made is apparently a very pricey venture. I plan on using the rubber-fiber (a black thin gasket, similar to the orignal ones), and coating this gasket in the orange gasket-maker material. I used this method when rebuilding the Weed Eater motor currently mounted to the scooter, and the motor runs, but there are so many problems with the motor, it would be hard to even pinpoint it to being the gaskets or otherwise.

I was wondering what everyone else here uses for gaskets on the HomeLite motors.

Lastly, I was just wondering a general idea for pricing on shipping for these rings -- would any of you think it's suitable to send them through regular mail, or would it be better to have them shipped? I don't mind the $12 USD figure (about $18 CDN I'm guessing).

If it is of any consequence, I checked on the identification sticker on the motor, and it says the UT No. is 20541.

I went on to the Outdoor Distributors website, and found that the Part Number for the piston ring says it is 96935. When I entered that number into the search, however, the search came up with nothing. When I entered the code posted above, it gave me a price of $3.78.

Thanks again!
Khany2002

You will really like Frank's rings. They work very well and he's a great guy. Shipping will be regular mail, and won't cost much more than a letter to send. He probably has the ring in stock, and if not he'll make one in a day usually. Price is $9.00 I believe.

I don't use a gasket between the cylinder and the block, as leaving it out raises the compression a little and helps power. What I use there is a sealer used for motorcycle crankcases called "Yamabond". Loctite makes a similar sealant.

For the exhaust, I just use a medium coating of silicone. This is really the only place you should use silicone on these motors, as it does not work well when exposed to gasoline.

Do not use any sealer on the carburetor gasket at all! If you feel like you just have to use something there, give it a thin coat of vaseline.

Do a search for Homelite 25cc engines here and you will find more of my posts and lots of info in general.

Good luck,
av8tor

Gasket material is called velumoid and can be bought at industrial suppliers. I think I used 1/32 in. on 35cc homelite cyl. bottom. Couldn't run this one without the gasket as the piston hit the head But worked OK on a 60cc homelite in a Byron Christen Eagle.

Fixitt Here good info guys, could use that really thick baking alum. foil, alot of the build up due to use and lower quality mixing oil also.