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Post by Urbanchainsawer on Aug 26, 2009 18:55:08 GMT -5
Gurus, This is a simple saw, so why is it giving me fits? Good spark, 125 PSI cold, correctly rebuilt HL141, good fuel lines. I cannot get it to consistently idle. I get a few pops on every pull, and sometimes a short idle at different adjustments. I even went as far as pulling the welch plug. It seems that I have tried every combination of hi lo and idle adjustments. Pulled the reed valve and it is tight. What am I missing? Do I have a crap carb like it sounds that CBFARMALL has on his 410 in the previous post? It is an elementary carb- what gives?
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Post by MCS on Aug 26, 2009 22:18:59 GMT -5
Will it run at high speed It could be a really bad crank seal. What is the history of the saw? With the needles each turned out 1 1/4 turns it should run.
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Post by polardoo on Aug 26, 2009 22:30:37 GMT -5
Piston scored? Points out of adjustment? Fouled plug? Old gas?
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Post by Urbanchainsawer on Aug 26, 2009 23:44:24 GMT -5
Will not run at high speed, much less with 1 1/4 turns out. The previous owner said that it ran great until he messed with the carb. Plug looks good. Maybe I need to pull the flwheel and check the points for gap. For some reason I did not even think about that. That s why I correspond with you guys!
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Post by MCS on Aug 27, 2009 10:07:51 GMT -5
The carburetor should be assembled in this order: Main Body Metering Diaphragm gasket Metering Diaphragm Diaphragm Cover Pump gasket Pump diaphragm Pump body cover.
Metering lever flush with bottom of chamber and do not alter spring tension. The fuel pump has to overcome this tension and this tension is very soft.
Make sure the holes in the gaskets and diaphragms match the holes in the the body and covers. Don't overlook the impulse hole from the crankcase to the pump.
Since you don't know what the last owner did when he messed with carburetor, you have to check everything.
If you squirt some fuel mix into the carb, it should run for a couple of seconds. Does it do this?
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Post by Urbanchainsawer on Aug 27, 2009 15:51:11 GMT -5
Like I had mentioned in an earlier post, it will at least pop on every pull and run for a few seconds at best. As for the carb rebuild, I'm positive that it is correct, including the lever adjustment.
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Post by sugarcreeksaws on Aug 27, 2009 16:55:48 GMT -5
Check the gas line. Sounds like it may be getting some air.
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Post by redsqwrl on Aug 27, 2009 19:34:33 GMT -5
Points.
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Post by Urbanchainsawer on Aug 31, 2009 17:21:08 GMT -5
Still no advancements. Points are good. Fuel lines are good. Same thing, a few pops on every pull, but no idle. I do like challenges but !! Condenser leaking???
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Post by polardoo on Aug 31, 2009 21:19:21 GMT -5
If you have a decent timing light, hook it up to a battery and the saw and watch your spark while cranking, maybe with a helper. That may tell you something.
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Post by MCS on Sept 1, 2009 15:10:43 GMT -5
Question Are you able to flood the engine with the choke on and cranking it a few times? If you are confident the carb is good then the ignition certainly become a suspect. Points are easy to check, the coil takes a little more and a meter, and the condenser can be tested to some extent with a ohm meter. Some digital meters offer a capacitance check and if you have one, the capacitor should measure about .2 microfarads. There are a couple of threads under Tips and Tricks that cover testing the ignition system. When you test for spark by cranking with the rope and the plug grounded you should see a spark with an easy pull, one that takes about a second to use all the rope.
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Post by mikem on Sept 6, 2009 12:26:25 GMT -5
Question Are you able to flood the engine with the choke on and cranking it a few times? If you are confident the carb is good then the ignition certainly become a suspect. Points are easy to check, the coil takes a little more and a meter, and the condenser can be tested to some extent with a ohm meter. Some digital meters offer a capacitance check and if you have one, the capacitor should measure about .2 microfarads. There are a couple of threads under Tips and Tricks that cover testing the ignition system. When you test for spark by cranking with the rope and the plug grounded you should see a spark with an easy pull, one that takes about a second to use all the rope. I find it is sometimes impossible to keep the plug adequately grounded against the saw, especially when pulling the saw over to test for spark. Tip: Take about 18" of good heavy 12 volt wire and solder a large aligator clip to one end and a small alligator clip to the other. Attach the large clip around the base of the plug and the other to any metal ground on the saw. I usually use a cooling fin. This will allow you to get the plug out where you can see the spark(if any) and makes it much easier to test.
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Post by Urbanchainsawer on Sept 6, 2009 14:41:08 GMT -5
Well, the C52 runs like a champ. I new that I had good spark from the beginning. Mikem, I definately use an alligator clip test wire to check spark. I knew I had 125 psi of cold compression. Carb was rebuilt correctly from experience. Points were gapped correctly and condenser read good mfds. So what was it? Sugarcreek Joe wins this one. Somewhere on the fuel lines between the filter and the carb was sucking a miniscule amount of air. Just enough to kill the saw after running for a second or two. I took 18" of brand new 1/4" id fuel line and connected it to the Tillotson 141b. Then I ran it directly thru the gas cap opening and into the gas. Adjusted the hi and lo at 1 1/4 turns out. Choked it and pulled three times to get the gas to the carb and get a pop. Pushed in the choke and pulled again. Not only did it run great, but I didn't even need to make further adjustments! I remedied the hose issue and now its ready to cut. It feels good when you finally figure this stuff out. Thanks to all of the great tips at HOH. I love this hobby!
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Post by MCS on Sept 6, 2009 19:11:21 GMT -5
In the original post you made the above comment and from that some assumptions get made. Fuel lines and fuel filters are the most common item that will affect these old saws and the only way to eliminate related problems it to actually replace them. Also, many times we never hear the "fix" so thanks for the update. What does it have for chain? 404 or 3/8th
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Post by Urbanchainsawer on Sept 6, 2009 19:22:46 GMT -5
Believe me, I would not have mentioned good fuel lines if I did not think that they were. In every respect, they appeared to to be good. Key word- APPEARED. More than one lesson learned here. You guys remind me to be thorough. There is not one person on here that has not had a stumper that turned in to a DUH! It has a freshly sharpened 3/8" chain on it. Thanks again.
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Post by 925fetish on Oct 3, 2009 11:24:54 GMT -5
i ha a c72 do the same thing to me after a carb rebuild and all it was is the fuel line was letting it suck air around the inlet simple things will get you zip tied it and years later im still riding it through oak trees
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