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SOS - Save Our Saw


nvisser's Avatar
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09-28-05, 07:29 AM   #1  
SOS - Save Our Saw

Time to cut some firewood before the snow flies here in Wyoming. I have a McColluch ProMac 610 chainsaw that does not want to stay running. It definitely has had some old gas run through it (and sitting in it). Last time I used it (a year ago) with some old gas, and I had to keep it revved by hand to keep it going. I know it was proably a bad idea to run the old gas. I have fresh gas in it now. I hope you can give me some advice on how to revive it without having to take it in for a repair.

I can fire it up, but then it either dies at idle, or when I try to give it gas it dies. I have removed the spark plug and cleaned it (did not appear "fouled" to me). The air filter is clean. I also turned the "idle" screw a quarter turn clockwise in hopes of giving it a little more juice at idle speed (to no avail). There are two other adjustment screws at the carb labeled "lo" and "hi" (but I don't know what to do with these, so I did not mess with them).

As you can probably guess I know practically nothing about small engine repair and I hope to avoid paying somebody to do it for me. So, what do you think? Can anybody give me a diagnosis, and some steps to try to fix it?

Thanks!

Nick

 
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goldstar's Avatar
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09-28-05, 05:14 PM   #2  
I'm not a pro but it sounds like the carb needs a good soaking in cleaner.
Bad news is, if I remember correctly, McCullough. is out of business and parts, if needed are hard to come by.

 
repair_guy's Avatar
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09-28-05, 06:47 PM   #3  
Yes I agree, your saws trouble is in the carburetor,which it has a walbro carb.on it.You might still be able to get that carb.rebulid kit at a local small engine shop.Other wise you should might better be thinking about buying another brand of saw because McCullough. is out of business and "IF" you can still get those WY carb.kits anymore,that's the only McCulloch part left that you can still get.

Poulan or homelite both makes good saws for the home owner.

 
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09-29-05, 12:21 AM   #4  
As far as I'm aware, homelite is gone now too.

Try this first....Back the screw marked high out a full turn and try to start the saw at full throttle. See if it will run. If it runs at full throttle, keep it running at full, but work the choke back and forth. Turn the choke on for a second, but take it back off before it dies. Do this a few times and see if it will idle. If not, back out the screw marked low 1/4 turn or so and repeat. You may be able to get this thing running without tearing into the carb, but it may take a little adjusting. Once (if) you get the carb cleared out, you may have to reset the high and low screws.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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09-29-05, 10:05 AM   #5  
deanw
Sounds like you have some varnish build up. If cleaning and mixture adjustment is not the answer, then I would suggest ordering a repair kit. The McColluch Pro Mac 610 should have a Walbro HDB-6A carb. This is now a HDB-6-1 and has a diaphragm/gasket kit part#D10-HDB available for under $10.00. MucColluch is now being manufactured by MTD and there are still quite a few parts for the older units out in the market. McColluch is now manufacturing electric power tools and mowers as well as power generators. Homelite is owned by TTI (Techtronic Industries) who also manufactures Ryobi and Ridgid woodworking tools. TTI has purchased the gas powered portion of Ryobi back from MTD and are putting out gas powered units being repaired by Homelite service dealers. Removing the metering diaphragm cover and diaphragm should reveal a clogged up main jet and inlet needle. Good luck!

Dean


Last edited by deanw; 10-19-05 at 02:11 PM.
 
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09-29-05, 12:36 PM   #6  
deanw mentioned a kit that begins with a "D". This is a diaphragm-only kit. I suggest buying the full kit which will begin with a "K". nvisser, since you have no experience with small engines, I suggest removing the carburetor and taking it to a reputable chainsaw repair shop and let them recon it for you. Hopefully, the shop you take it to uses a bath type cleaner such as Napa #6401 or similar. If you're a first timer at small engine repair, this is a tricky one to start out on...carburetor service, especially two-stroke carbs.

 
nvisser's Avatar
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09-30-05, 06:34 AM   #7  
Thanks guys! I got it running at it and seemed to work better after I used it a bit (and I worked the choke as suggested). I also backed off the hi screw. Maybe just running fresh gas through it helped clean the carb. Anyway, now it will idle for at least a 10 seconds and usually won't die if I throttle it. At least it starts easy!

I know that's pretty lame performance for a tool that I will be using a lot over the next weeks, but it has me going.

I will probably pull the carb and have a shop clean it. Then again, I might fiddle with it myself just for fun. What's the worst that can happen: I'm out ten bucks and my saw doesn't work. Thanks for the carb info and part numbers!!!!

One more thing: Can you give me the summary of what the hi/lo screws do to my carb, and what the principles are for adjusting them. Obviously they affect the mixture, but how? What behavior from the engine suggests that I turn which one (and which way)? Alternately, do you know of any sites that teach "Small Engine 101."

Thanks again!

 
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09-30-05, 12:25 PM   #8  
The low (L) circuit needle adjusts the amount of fuel delivered at no throttle and to a very minor extent during part-to-full throttle. The high (H) circuit needle adjusts fuel at part throttle to full throttle. You will want to make any adjustments to them once the engine is at operating temperature (3-4 minutes of part throttle acceleration). Generally, they will be in the vacinity of 1 1/8 turns out from seated. Generally that is. There are variables that affect these adjustments and would be too lengthy to discuss here. Most two-stroke-cycle engines are very finicky when it comes to their adjustments and if either are off by as much as 1/8 turn will send it in a tizzy. The majority of todays 2-stroke carbs are non-adjustable so that there is no possibility of misadjustment.

 
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10-02-05, 01:16 AM   #9  
Deanw,

Does that mean we will be seeing homelite branded products once again?


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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10-02-05, 02:38 PM   #10  
everyone posted what i would have posted,

id still clean the carb and check that fuel screen in the carb.

Ive worked on a few chain saws and the sw dust plays havoc with them after while.

I hate to say it, but i seen more people when sumething is not running right, right away start trying to adjust it,

most of the time, on those carbs, zuma, walboro and so forth, its not the adjustment out of wack, just a dirty carb or fuel filter,

Not always but 90% of the time.

Those carbs are on so many different small engines, leaf blowers, weed eaters, gas scooters, gas r/c (boats, planes)

Parts are pretty easy to get for them or find used.

We got a local repair shop, 2 houses down from me, and i bet he throws 2 or 3 a week away, just cuz when people see the labor rate, they just buy new.

All due to just needing a new carb kit or line or fuel filter. Sure you get the ones blown or failed coil. But on a $60 - $120 unit

and carb kits you can get for under $12.00, and if you can try and do it yourself, hay ya saved some money in getting a new one.

sporty

 
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10-03-05, 09:07 AM   #11  
deanw
Posted By: cheese Deanw,

Does that mean we will be seeing homelite branded products once again?

Well, not really. Homelite is manufacturing string trimmers and pressure washers under the Ryobi name as of jan 05. Any model number starting with an "RY" (for example: Ryobi "RY80030" 3000PSI pressure washer) will be a Homelite model. If warranty work needs to be done, it will need to be done by an authorized homelite service dealer. This has a bunch of my MTD service centers confused as well. The last of the old Ryobi models by MTD (handheld) have a serial number which start with a "41". So no, you will not see the name Homelite.


Last edited by deanw; 10-18-05 at 10:52 AM.
 
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10-05-05, 12:04 AM   #12  
Thanks Dean. I hate to see another name dissapear from the market, but at least the company still exists I guess. With all these companies being bought and sold and absorbed, I figure one day there will just be 2 or 3 companies that own everything...lol I don't even try to keep up with it anymore. I find out through the grapevine now.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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