Old Chainsaw - won't keep running
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From: Wyoming
Old Chainsaw - won't keep running
I am trying to get an old McCollough Eager Beaver running. I haven't used it since 1998, and was attempting to get it going last weekend. It's got a 2.3 cu.in. 2 stroke engine, and I put a new spark plug in it. It will start okay, but after about 10 seconds it will die. If I wait 10 minutes, it will start again, run for 10 seconds, and then die (even at WOT). Whadda ya think - clogged fuel line? Float? I've replaced the air filter too. I've never tore down the carb before, and it ran great from ~1992 - 1998.
Elder User
Joined: Nov 2005
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From: Buckeye Country
You gotta rebuild the carbs on saws every three years anyway. Get on it, and replace the fuel line while you're at it. Swish out the fuel tank as well; that saw's probably gummed up from head to toe. The off-season is what kills saws and that's why you've never seen this before.
Logistics Pro
Joined: Nov 2004
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From: Lancaster County PA
I'd check the easy stuff first.
It sounds like it gets fuel then runs out, so I'd change the fuel filter in the tank and put new fuel lines on it, in case one has a small crack in it.
If fuel is flowing through the carb for 10 seconds, it should keep flowing through the carb, IMO.
This is likely a diaphragm type carburetor and wont have a float. Rebuild kits are usually available to replace diaphragm and needles, etc.
It is not hard to do, just lay everything out in the order of disassembly so you can put things back in in the correct order.
It sounds like it gets fuel then runs out, so I'd change the fuel filter in the tank and put new fuel lines on it, in case one has a small crack in it.
If fuel is flowing through the carb for 10 seconds, it should keep flowing through the carb, IMO.
This is likely a diaphragm type carburetor and wont have a float. Rebuild kits are usually available to replace diaphragm and needles, etc.
It is not hard to do, just lay everything out in the order of disassembly so you can put things back in in the correct order.
Cargo Master
Joined: May 2003
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From: Earth
I have quite a few 2-stroke engines that I use, I've never heard of rebuilding the carbs every three years. What you should do is clean the carb. I have to do this on my snowmobiles at the start of every season. If it was used 8 years ago and then sat, I'm betting the carb is pretty gummed up. Also, you might check the screen on the exhaust. I had a weedwacker that would tend to clog up the screen on the exhaust and would choke itself out and quite. I would clean that and it would run fine after that. Also, make sure you are running fresh fuel in there that is mixed properly. Good luck!
Elder User
Joined: Nov 2005
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From: Buckeye Country
You can have a thousand two stroke engines and as long as you run 'em they'll be fine; it's when they set that they gunk up. IF I was taking the trouble to clean a carb, I'd sure rather drop in a new diaphragm and jets than have to go back and re-do it. Running too rich will clog your spark arrestor screen, as will mud-dauber hornets... It comes down to hours and post-season maintenance, a hundred hour saw is gonna need more attention than a weekend warrior saw
Last edited by TigerDan; Dec 23, 2006 at 03:49 PM. Reason: One of those weird repeat things...
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From: Wyoming
THe exhaust was the first thing I degunked when I was going over it. Thanks for the tips - I'll try to get into the fuel system. I didn't know it even had a fuel filter. Don't have one on my dirt bike - should I? It runs the same premix fuel.
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From: Buckeye Country
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Posting Guru
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From: Northern Massachusetts
main jet in the carb is clogged a ssuggested open up and clean the carb make sure you clean the varnish out of the main jet.
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Fleet Mechanic
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From: cape may county NJ
No ifs ands or buts about it a saw sitting that long will need the carb rebuilt and a new fuel filter.Some of the Macs are easy to work on. How old is the saw can you see the carb and get to it without much trouble and dose it have a primer
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From: In a hole
fill the carb with sea-foam deep creep, and let set for ten min.
start it and spray more sea foam in it till it stops, then fill it up agin.
i did this with a homelite super xl that had sat for 5 years and it cleard it up.
you may have to do this sevrail times.
start it and spray more sea foam in it till it stops, then fill it up agin.
i did this with a homelite super xl that had sat for 5 years and it cleard it up.
you may have to do this sevrail times.
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From: Wyoming
I messed with it again this weekend. I sprayed the carb with carb cleaner, then gave it a pull. It started up 1st pull and ran like a bat outta hell for about 30 seconds, then died again. Thought I had it made there for a moment.
Well, I got the fuel filter pulled out of the tank and blew it out backwards with air. It didn't look too bad. It wouldn't start again, even with the fuel filter off. I set it aside after looking for a way to get at the exterior of the carb - no obvious way to get the plastic housing off.
I haven't tweaked the H, L, and I screws yet. Actually, I've never turned them at all. Would backing them in and out a few times dislodge any gunk? What do they do? I'm guessing I is the idle speed needle valve, but what about H and L?
Well, I got the fuel filter pulled out of the tank and blew it out backwards with air. It didn't look too bad. It wouldn't start again, even with the fuel filter off. I set it aside after looking for a way to get at the exterior of the carb - no obvious way to get the plastic housing off.
I haven't tweaked the H, L, and I screws yet. Actually, I've never turned them at all. Would backing them in and out a few times dislodge any gunk? What do they do? I'm guessing I is the idle speed needle valve, but what about H and L?
Elder User
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From: Buckeye Country
Spike, yer gonna have to suck it up and rebuild the carb, man. There ain't a shortcut made that can make a saw that's been sitting that long run without doing some work! Try to find the manual on the 'net, tear it down, pull that carb apart and wash it in carb cleaner is all you can do to ensure it will start and run. Otherwise, take it to a shop.
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