Timberman 45cc 20 inch saw runs 30 to 40 seconds then quits.

[kingbee]

I'm hoping, I'm placing this request for help in the correct place. I new here and having a little difficulty navigating around.

I have a 14 year old Timberman 20 inch with a 45cc engine. It probably doesn't have more than 20 hours of run time since new. Like many IRMA took a good swing at me and I need it to run... "a lot" so I can get the tree off the roof and clear up the other 9 big oaks that came down around the house.

It would start, and would idle or run at speed for about 30 to 40 seconds and then stall.  I took the carb apart except for the jets and after soaking it in carb cleaner for a couple of days, I got a new carb kit (new diaphragm, gaskets and jets, 'new jets not installed, note saw has less than 20 hours run time'), installed it, along with a new primer bulb, fuel hoses, air and fuel tank filters, cleaned the tank out, and it will start right up and stall after running 30 to 40 seconds.

The primer pumps up tight, choke works, new clean non-ethanol gas mixed 50:1. Prime it, choke it and it starts on second pull.

Now I am 72+ and it takes me a long time to do things, I need to get it running, and get the place cleaned up before my time expires.

I am at a loss right now and need some guidance... all guidance is appreciated.

Ken (kingbee)

[undee70ss]

The gas tank might not be venting. As a test, leave gas cap cracked open (you may have to have less than a full tank to do this). If it stays running with cap cracked open, tank is not venting.

[onlyhomelites]

can you keep the saw running any longer by closing the choke a bit? If Undee70ss' suggestion works, there should be a bronze filter with a duckbill valve behind it on the starter side of the fuel tank...the picture I found was terrible, but it looks like that starter has to be off to find it. Another idea is to check the spark arrestor screen on the muffler to make sure it isn't plugged.

[kingbee]

The choke doesn't help at all. I check the spark arrestor tomorrow. The only filter I found on this unit is one in the tank, one air cleaner, and one of the fine mesh screens in a carburator passage. I changed all those. I had the pull cord assy off and I didn't see anything that looked like a filter. I'll pull it off again in the morning, and look again. What does that bronze filter do?

Thanks fellows, I appreciate the quick reply's and guidance. I will do those check first light tomorrow.

Ken

[undee70ss]

Sept 27, 2017 19:04:38 GMT -5 kingbee said:

What does that bronze filter do?

Thanks fellows, I appreciate the quick reply's and guidance. I will do those check first light tomorrow.

Ken

Under the bronze filter is a check valve (duckbill). The purpose of the duckbill is to let air in but not let gas out. When the get old and/or from ethanol gas, they can turn to goo plugging the vent. When the vent is plugged, and as gas is being used, a vacuum will form in tank. The carburetors fuel pump can not overcome this vacuum and will stop pumping fuel. The purpose of the bronze filter is to keep dirt and sawdust out of the duckbill.

[kingbee]

undee70ss, does you handle involve submarines? I was on the USS Sea Cat SS399 and USS Spadefish SSN 668.

The problem appears to be that bronze screen and valve. It is letting gas drain out of the tank into the saw casing. Can you tell me how to get it out so I can replace it, if that is possible.

Many thanks for the help.

Ken

[undee70ss]

Sept 28, 2017 11:07:23 GMT -5 kingbee said:

The problem appears to be that bronze screen and valve. It is letting gas drain out of the tank into the saw casing. Can you tell me how to get it out so I can replace it, if that is possible.

Many thanks for the help.

Ken

Usually (at least on the older saws) you pry it out. The older ones, the bronze filter had a step that one can hook with a pick to grab it. Looking online at replacement parts for your saw, looks like there is no step on your bronze filter. I've never worked on a timberman, but it's possible, if you can't get behind it to push it out, you may have to destroy it to get it out. ( drill it out etc...). I would try using a sharp pick and prying it out.

The larger question is since it is leaking gas, then the tank is venting, if you start saw and hold in a way that it doesn't leak, will it run longer than the 30-40 seconds?

[undee70ss]

[kingbee]

I prime it up, pull the choke, pull the cord, and it starts on the second pull...usually, even when cold. It won't continue even with the choke pulled or half way. It seems like it is running out of fuel, when the tank is half full.

Is it the bronze screen that is supposed to keep the gas from leaking out the top or the duckbill valve? It seems the tank is pressurizing and pushing the fuel out the bronze screen. There is not vent on the fuel tank cap that I can find.

I talked to the small engine shop nearby and they say it would be a month before I'd get it back. I guess I'm going to purchase a new unit in a slightly smaller size. I see both Stihl and Husquarvana had sales on their 14 and 16 inch saws.

If you were going to buy one now, would you get the Stihl or the Husquvarna?

thanks, Ken

[onlyhomelites]

My only experience with either brands in small saws is the Stihl MS-210 and I can emphatically say that I DO NOT recommend that saw or it's siblings!

[kingbee]

Thank you for the feedback. I always listen to good advice.

Ken

[undee70ss]

Sept 28, 2017 11:07:23 GMT -5 kingbee said:

undee70ss, does you handle involve submarines? I was on the USS Sea Cat SS399 and USS Spadefish SSN 668.

No. Everyone calls me undee because of my last name, I also own a 1970 Chevelle SS, so that's how I made my online name. I use to post on a lot of automotive forums.

[Deleted]

Sept 28, 2017 12:53:24 GMT -5 kingbee said:

I prime it up, pull the choke, pull the cord, and it starts on the second pull...usually, even when cold. It won't continue even with the choke pulled or half way. It seems like it is running out of fuel, when the tank is half full.

Is it the bronze screen that is supposed to keep the gas from leaking out the top or the duckbill valve? It seems the tank is pressurizing and pushing the fuel out the bronze screen. There is not vent on the fuel tank cap that I can find.

I talked to the small engine shop nearby and they say it would be a month before I'd get it back. I guess I'm going to purchase a new unit in a slightly smaller size. I see both Stihl and Husquarvana had sales on their 14 and 16 inch saws.

If you were going to buy one now, would you get the Stihl or the Husquvarna?

thanks, Ken

I agree with Leon (onlyhomelites), buy a Husqvarna 400 series, 435 or larger. I've had both Stihl and Husqvarna weed eaters and chainsaws, and while I like my older stuff better, the newer Husqvarna equipment has performed much better for me than the Stihl.

[undee70ss]

I have no experience with either brand, Ive always kept my old junk running. If I was going to buy new, I would buy from the best servicing dealer in your area.