1966 Homelite XL-12 ( the Blue one) 16″ bar.
Starts, ( added ele.ignition, no points) Runs, at about 1/2 tank gone, sputters and acts like out of fuel.
New fuel line, new filter, I AM missing the itty -bitty screen in the carb..TWO shops were supposed to have repaired it. First shop NEVER EVEN TOUCHED the saw and charged me 40 bucks to get it back..don’t worry, I am spreading the word about them crooks.
Second shop SAID they replaced the screen ( its the size of this o ) but DID get the hi/lo speeds running and fixed the fuel line/filter problem.
I think it’s something else..I THINK the cap is venting, cuz after a quick re-fill top off, it still won’t run at full power for long..so, maybe a short in the IG? Or still fuel prob? Even with the lil screen missing, I don’t see crud in that lil recess, like I did before the filter / line swap..can a 2cycl. Vapor Lock?
After it sets for a few hours, days, weeks, it’ll run like a raped ape for the first half tank..then back to sputter and stall.
I’m flummoxed,a nd shopping for a Stihl, but the $$$ is daunting right now….any thig I should be checking that I am obviously missing? Its a 32:1 fuel mix, all fresh.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
Replies
Duane, this happens in a stihl, but might be possible in that homelite.
The fuel additives-alcohol, methanol, tuonol........some ol, softens the fuel line and to a point, the inline fuel filter in the stihls-more so b/4, not so much now-they might have changed the rubber makeup. At any rate-when accelerating-the line collapses and starves it of fuel. Seems to start alright, but after warmup-can't get anything better than idle. Proceeds in time to no start due to the collapsed line.
A Great Place for Information, Comraderie, and a Sucker Punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
That's exactly right...and another thing to check is the fuel filter in the tank itself. If they are starting to get plugged, it will starve for fuel and collapse the line.
He may need a new fuel line too. The toxic gas can turn it into mush and it will collapse very easily.
It's all new, from the tank ( drained and flushed) to the carb inlet.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
re: all new
did they change the fuel feed line inside the gas tank? A hole in that line will be covered duing the 1st portion of the tank and then when the level drops it will bleed air into the gas line.
OK, I didn't read your first post very well! How about checking to make sure the fuel line in the tank is not too long. Could it be hitting the bottom of the tank and then curling back up so it "runs out of gas" when the tank gets lower on fuel? Maybe they installed the wrong length fuel line at the repair shop.
If it's the original carb, the diaphragm could be stretched. After 40 some years, a carb rebuild might be in order.
Chainsaw carbs are very simple, but they have minute little passages that you might want to blow out. You could replace the diaphragm at the same time.
Are you sure the cap is venting properly?
I had one of those saws back then.
Might be the diaphram, I've had it open so many times, it may be toast. Just four screws and a Swiss army knife is all I need to rebuild the carb..LOL
Gonna drill a hole in the cap, even tho' I think its venting. Fuel line is short if anything, the bell where the filter /weight attaches was cracked, and I had to cut it off.
Thanks all..I'll get to the bottom of this yet, probably right after I get a new saw.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
Try the "ArboristSite.com"...under their equipment forum...chainsaws. A jolly crew over there...Friday...quittin time...
rustbucket
Sphere, I think that many two cycle carbs pump air into the tank to make up for the gas that gets used. These gas caps won't have any vents.
Two Cycle engines usually use the simplest carbs available.
I've yet to see one with an air pump.
In fact all three of my dirtbikes have gas cap vents.
You may be thinking about closed loop fuel injection systems
Of course you're right about the dirt bikes, used to race 'em when I was young. I should have narrowed it to chain saws. I know my stihl has a solid cap. The carbs are called pulse carbs, and it is the pulsing action on the diaphragm that draws in the fuel and sends air to the tank.
Not this one, it's prehistoric.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
What would be a good material to make a gas line out of, to counteract that ?I mean besides metal. Has to be something flexible for the application.Teflon ?
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I don't know. After replacing a couple, stihl seems to have come up with maybe a replacement that doesnt deteriorate as easily. The easy prevention was to be running it dry and not refilling till next use-yeah right.
In the stihl the inline filter is part and parcel to the gas line. I suppose you could cobble up a way to replace the line-patch in the filter and then line to the carb. All of that sits right in the tank.
Mines working well now, so I just don't think about it anymore.A Great Place for Information, Comraderie, and a Sucker Punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
I had a Stihl 041 for about 30 years. The fuel line deteriorated & cracked as described after about 2 or 3 years. Replaced it with some hypalon (sp?) tubing (the clear stuff from the hardware store). That worked fine for the next 27 years or so.
.....can a 2 cyl. vapor lock?
Yes, I had a Stihl 051 years ago that would do this. Turns out it had developed a small crack in the muffler that would open up and let the heat escape upwards when it got hot.
Very hard to see until I took the muffler off. It ended up semi-melting a plastic heat shroud above the muffler. Thats how I found the crack.
Same symptoms as yours although mine would not run a half a tank before it shut off. After it cooled off it would crank easily and run good again for a little while.
I got the muffler welded up and made a sheet metal shroud to replace the damaged plastic one and cut for years with that saw.
Maybe worth a look.
dug
Might not be the problem but its sounds just like my MIL John Deere mower. Her problem is the gas cap. It isn't allowing any air in so the engine drawing the fuel is literally creating a vacuum to the point that the plastic tank gets sucked in on itself. When it starts to stall out, shut it down and open the cap. If you hear it suck in air, then that could be the problem. Her mower needed a new cap and it was fine. Of course, a John Deere gas cap is a gold plated diamond encrusted affair that comes pretty dear but dems the breaks when you buy the best.
My Stil had a problem accelerating off idle so I took it in.
They explained that the rubber diaphram in the pumper carb gets stiff.
I think it is the part that pumps the gas so it is pretty big in the carb.
Try replacing it if they have a new one.
Friend of mine has a VW bug. Early 70's.
It would run for maybe 20 or 25 minutes. Then? Power dropped off and it died.
Went thru everything. Engine was rebuilt, took it back to that shop and got nothing.
Noone could figure it out.
Took to some old German trained mechanic in Allentown. He listened, looked at it, pulled off the gas cap and ran a drill bit thru the little vent hole...................Problem Solved.
The vent wouldn't let in enough air, and it took about 20 or so minutes for that little aircooled four to draw in enough fuel, to create enough of a vacuum so that the pump could no longer draw fuel against it.
That's why when he let it sit for 10 minutes or so it ran again. Had plenty of time to draw air in thru the half clogged vent and break the vacuum.
When I first read your post, I thought of a plugged vent in the fuel cap. There does need to be a one-way vent to get air into the tank as the fuel is drawn out (think finger on the end of a straw not allowing water to drain out). To check this problem, simply loosen the cap and try starting it again. It should run fine for at least a few minutes. I would advise against drilling a hole in the cap unless you are planning on replacing it. You don't want gas to leak out while you are cutting wood.
If the engine is cold, will it run with a half tank of fuel? I ask this to determine if the failure is heat related. If heat related, I suspect an ignition problem such as a bad coil. The windings get hot, expand and short out. After the coil cools for awhile it will run again. To check this, you need to check the spark when the engine dies. The easiest way to check this (if you don't have a spark tester and if it is possible with your model saw) is to unscrew the spark plug right after the engine quits, connect the wire to the plug, ground the plug base to a bare spot on the engine and crank the engine over. You should have a bright blue spark. If not, wait till the saw cools and try again. If you have spark then, replace the coil. Be careful when you do this test that there is not raw fuel on the saw. I once set a customer's saw and half my work bench on fire...
Another heat related possibility is advanced ignition timing. This can cause the engine (and thus the fuel system) to overheat. If the fuel get too hot it can "boil" causing a "vapor lock". If this is the case the saw, when cool, should run with any amount of fuel in the tank. So back to my earlier question, will the engine run with a half a tank of fuel when it is cold?
Keep me posted. As a small engine mechanic in a former life, I am always interested in finding a solution.
I had to geta new cap a ways back, when to Orig. vibrated off and got lost..now I wonder..it seems to coincide wit these issues. It was an old cap from a saw shop.
I'll delve, and hope it ain't ele. Cuz that means back to the shop.
If and when I get it ironed out, I'll share the details.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
Can't help with your problem. But the fact you may have intimate knowledge of how a raped ape runs intrigues me.
I'm curious how you came about this info and were you the perpitraitor of the act that induced the ape to run.
As Piffin or IMERC might be able to share with you, had you spent more time before the act, getting to know the ape and using one of Martys many famous foreplay techniques, (ask any librarian east of the Mississippi), she might have stayed with you afterwards. And you would not be at risk for breaking the law.
Just trying to be helpful this Holiday Season.