Walbro Carb for UT 20537 Trimmer Engine

[SpiderSpartan]

I'm getting ready to start my second motorized bike. Gonna go friction drive this time. I've got another old Homelite Trimmer, but I can't get it running quite right. The guy I got it from thinks the carb was bad and that matches the symptoms I'm getting. If the engine hasn't been started for a while it will act like it wants to start and usually it actually will, but I can't keep it running. I've been trying to find a new carb for the engine, but I can't figure out what model it is. I do know it's a Walbro. The only numbers I can find on the carb are 5 5-458 and 2-46 2. The trimmer is a 260 UT 20537 25cc 1HP. Does anyone know what model carb I'd need to replace this or where I could get one? Thanks for any help.

Here's a picture of the carb.

[deacon]

I'm sure you have done this, but if not you might try dumping all the gas out then add about an ounce of gas and spray carb cleaner into the tank. Take the plug out and pull it through several times. Then dump that gas and put in some fresh gas and try to run it.

If it seems better but not right do it again.

Secondly about any carb from a weed whacker will work I think. I used a 31cc ryobi carb to replace a poulan chain saw carb that was totally different. I don't honestly know how much difference there is in them.

[SpiderSpartan]

Yeah, I ran carb cleaner through it. I'm just afraid to buy one off ebay or something and then have it not fit. Maybe I'll put another post on Craig's list and see if I can't get another engine for free parts.

[deacon]

Tell me does it have a plate and moving lever for a choke and a squeeze bulb on it... How many ccs is the engine.

And did you try to adjust it, of course you did I'm sorry to ask all this I have an engine doing the same thing sorta and I know it isnt the carb cause it has done it with two carbs. One of them was bran new.

I have the one I took off the ryobi is why I asked.

[SpiderSpartan]

It's off a really old Homelite 25cc engine. I adjusted the low end and it doesn't seem to make a lot of difference really. It's got a little connector for the choke just like for the throttle. A rod goes through it and then through a plastic piece that gets slotted into the plastic engine casing. No squeeze bulb on it. I think I'm going to try and take the carb off my newer homelite and see if I can get it running with that. Only problem is, I think the carb on the newer homelite has two lines coming off of it, while this one only has 1 line. I'll be sure to take some pics and post them. Check out my site. There's some shots of when I took it apart to check the gaskets visually.

[deacon]

It looks like a standard bolt up to me. Stick you good carb on it and see if it wont fire. I have a 25cc carb that is working You will have to tinker with it, but it should do you some good. You will probably have to make a choke and air filter I'll see what I have.

[deacon]

I just remembered the 25cc has a built in choke with a plastic lever. Im not sure but I think my good carb has a throttle control not the plastic lever it works much better and I used it on both kinds of engine. If you want to give it a try let me know and I'll stick it in an envelope and mail it to you,

It does have a bulb and second line but that wont make any difference you will just have to drill a return line hole in your gas tank and add a line for it.

[Easy Rider]

Try using a Walbro 603 but first check to see if your pulse hole is blocked by the gasket. It's between the manifold and the carb.

[trackfodder]

go to the mower shop and get a rebuild kit. Be very careul on disassembly. Many tiny parts and springs that can disappear in an instant. The diaphragm usually fails, but sometime grit plugs stuff. KW