Homelite saw won't stay running

[Skier76]

I was given a Homelite Timberman 45 (18" bar, 45cc engine) a few years back. The unit would fire up, but when you gave it gas, it would just bog out. I cleaned out the carb, but it still wouldn't stay running once you squeezed the throttle. I had also put in a tankful of fresh gas and oil after I cleaned the carb. I had no use for it at the time, so I put in the shed.

Now I have a use for it want to get it running. I took it out the other day and after a few pulls, it fired up. But it still had the same problem; give it gas....'bwwwwwwwwwwwwaaaaaaaaaaaaaaaaaaaaaaaaaaaap' and it stops running.

Looks like the model number is UT10946A. I'm having a heckuva time finding a manual or parts list online.

I did a few internet searches for saws with a similar problem. Seems like the carb may need a rebuild kit?

Any thoughts on where to start?

 

[LLigetfa]

Carb probably just needs a good cleaning. For starters, unscrew the high jet and try to run it for a minute. It may be enough to dislodge some dirt. Take the long red tube from a WD40 can and spray it in the threaded hole where the jet was. Run it again for a minute and then put the mixture screw back in and try adjusting it. If that doesn't get it, you'll have to take it apart.

The pickup filter in the tank might be shot letting the carb pick up dirt again.

 

[Skier76]

Excellent. That's a great place to start. Anyone know what the factory settings are for the carb screws?

 

[LLigetfa]

3 half turns (1-1/2 full turns) is a good start in most cases.

 

[kevin j]

also check the fuel filter, the fuel line from tank to carb, and the impulse hose that operates the fuel pumping diaphragm.
sounds like it is not getting fuel supply.

k

 

[Skier76]

also check the fuel filter, the fuel line from tank to carb, and the impulse hose that operates the fuel pumping diaphragm.
sounds like it is not getting fuel supply.

k

Will do! I'll take pics and post those as well. Thanks guys!

 

[Skier76]

I messed with this for about 45 minutes tonight. I took the carb apart, cleaned it out and rebuilt it. Everything looked to be OK. Same deal...it'll run, then just bog out.

I must be getting old....I just don't think this thing is worth spending any money on at this point. I got it for free. I'm just going to get a new saw. Maybe one of those 16" Echo's from the Depot.

 

[LLigetfa]

Did you try loosening the gas cap? Maybe a plugged vent.

 

[Skier76]

That's one thing I didn't try. I'll give that a shot before throwing in the towel for good. Thanks!

 

[tjnamtiw]

That's one thing I didn't try. I'll give that a shot before throwing in the towel for good. Thanks!

If it has a Walbro carb on it, there's a little screen under the one end plate that is the 'final filter'. It can get clogged easily. Just pick it out, wash it with carb cleaner and push it back in. If it dies when you open the throttle, it is too lean.
I'm sure you'll find a lot of people who will 'take it off your hands'.....................

 

[Skier76]

I can't remember the name of the carb...it starts with a "Z" and had "Made in China" stamped under it.

 

[tjnamtiw]

I can't remember the name of the carb...it starts with a "Z" and had "Made in China" stamped under it.

Don't know. Of course, what DOESN'T have Made in China stamped on it today????

 

[realstihl]

ZAMA! It has a screen also. Don't give up on it. Good learning experience and you'll be glad you figured it out.

 

[tjnamtiw]

ZAMA! It has a screen also. Don't give up on it. Good learning experience and you'll be glad you figured it out.

Yea, it looks just like the Walbro carb. http://www.zamacarb.com/pdfs/TechGuide_2007.pdf
Don't give up on it. It's just a piece of aluminum! You're not going to let that beat you, are you? Check that little screen, get a rebuild kit for the diaphragms and check valves. If you have a primer bulb on it, that can also go bad and crack. Had that happen once. I use the Walbro's on my large scale model planes too and have had two dead sticks. One for the clogged screen and one for a hole in the diaphragm. It's a lot tougher when you're 100 feet in the air! Don't give up

 

[Skier76]

Thanks guys! That guide looks like it'll help. I'll give the carb one more teardown. I'll post pics too.

 

[tjnamtiw]

Thanks guys! That guide looks like it'll help. I'll give the carb one more teardown. I'll post pics too.

Yea, they really are pretty basic. Just make sure the passages are clear with compressed air and you have new diaphragms. The setting of the jets can be tricky so take your time there and do it first without a chain just for safety's sake.

 

[Skier76]

I'll give this another shot this week. Where's the screen? I've only seen the diaphrams when I took the carb apart. Do you mean the strainer on the end of the fuel line that's in the tank?

If you look at that manual, mine looks somewhat like the carb with the yellow choke lever.

 

[tjnamtiw]

I'll give this another shot this week. Where's the screen? I've only seen the diaphrams when I took the carb apart. Do you mean the strainer on the end of the fuel line that's in the tank?

If you look at that manual, mine looks somewhat like the carb with the yellow choke lever.

When you take off the one end plate, there should be a small circular piece of fine mesh screen kind of stuffed into a counterbore. It should be on the same side as the diaphragm with the two little flaps that are the check valves.

 

[karri0n]

You sure the spark is good? I had a hell of a time with a saw just recently tearing down, checking carb, filters, etc. The spark LOOKED plenty strong and the right color when out of the saw and I grounded it and pulled the rope, but I replaced the plug and the thing fired right up. It was exhibiting the exact same behavior you're describing. I smacked myself in the head after all that...

 

[karri0n]

hmm... Can you explain that further Pook? I can't figure how there could be more psi caused by the compression stroke than the amount of psi that exists at the time of ignition. It doesn't seem my saw sustained any damage from this anyway, but that's pretty interesting to me.

 

[tjnamtiw]

bad plug= bad news= if uncombusted gas overpressurizes the cylinder it can bust the piston rings & likewise for old gas

From his description, it really just sounds like his high speed adjustment is way off or his carb is gummed up after sitting for so long.

 

[Skier76]

Pulled the saw out of the shed after mowing the lawn. I'll give it another look tomorrow or Wednesday. I'll throw in a new plug for good measure. Worse case, I'll at least have a new plug for when I hopefully get it running again.

I did some googling on this saw and it seems that the chain brake is prone to failure on this model. I'll investigate that as well.

 

[tjnamtiw]

Pulled the saw out of the shed after mowing the lawn. I'll give it another look tomorrow or Wednesday. I'll throw in a new plug for good measure. Worse case, I'll at least have a new plug for when I hopefully get it running again.

I did some googling on this saw and it seems that the chain brake is prone to failure on this model. I'll investigate that as well.

That's interesting. The chain brake would sure pull that sucker down to parade rest! Get rid of that thing!

 

[Skier76]

It sounds like it may be a PITA to remove...but I think it's worth a look. Especially if it'll get the saw running again.

Here's one of the links I found: http://www.howtomendit.com/answers.php?id=141373

 

[tjnamtiw]

It sounds like it may be a PITA to remove...but I think it's worth a look. Especially if it'll get the saw running again.

Here's one of the links I found: http://www.howtomendit.com/answers.php?id=141373

Yea, the brake housing on my Husky 50 is also melted but the brake still works, SO FAR. It's really there to protect if you get a kick back, which happens if you are not watching what you're doing. I always cut with my head off to one side and never in line with the saw. Worst case, my collar bone takes a hit. )