Mac Timber Bear(?) Hard Starting Need Advice

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KATO

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Pulled out my Mac Timber, not 100% sure what model name it is but the sticker says MOD. 600134-24 , SER, 11-007608 . Have the OE manual but it's for 6 different models, anyway I thought It needed a coil (still might) but finally got it to run, problem is you can't always get it to start, especially when you want to use it. Got it many years ago at an Odd Lot store for a great price, it's a recon with a recon sticker w/ no model info on it just 3.4. Only used it once right after I purchased it, so I flushed out the gas tank with a few squirts of Gummout and fresh non-ethanol gas and used Stihl synthetic oil mix, carb and plug (gapped to 25) looked clean so I gave it a shot of start fluid and away me and my old arm muscle went. Took a long time, saw the spark on the plug so I figured the fuel was not getting to the chamber, then I read that the bar oil gets into the cylinder and fouls the plug. Sure enough, every time it wouldn't start and I cheched the plug it was oil fouled. So I continued to clean the plug and try again and again, I was almost going to quit when it started......thanked God, let it sit and tried again, it started fine. After it sat for several hours I tried again before I put it away and it started again. Now today, I wanted to use it and could not get it to start, so I went to HD and got the newer DJ8J with the fine center electrode and same results. After several plug cleanings and enough start fluid to make my wife look young again.....I quit and put an insurance claim in for a left arm. I'm pretty experienced at small engine repair so I would first go to a weak spark (or a beer).....any advice, am I doing something wrong?
 

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This looks like the Mac 605 and yes, they were notorious for the bar oil getting into the cylinder. I had one that would smoke a blue streak for nearly five minutes and fill the whole yard with smoke after it started. But, it always eventually started and ran, so I sold it to a guy who didn't mind that. For reasons I do not understand, my Mac 610 and 5700 do not do this. They start and run as expected.
 
That's another thing that it did, smoke like crazy. I double checked my oil ratio to see if I did it wrong, but I didn't. It ran great and never stalled while idling. Just would like to be able to start it on a regular basis.
 
Its not hard to break these down but im unsure how bar oil would get into the crankcase unless its thru the oiler pump? The oil reservoir bolts up to the back of the block..4 bolts there hold the cylinder to the base plate.

Sent from my LM-G820 using Tapatalk
 
If the diaphragm in the automatic oil pump fails then bar oil can get by into the crankcase since the automatic oil pump is operated by crankcase impulse pressure.

You may need to open the carburetor and give it a good cleaning and confirm that the metering and fuel pump diaphragms are clean and flexible.

Don't use starter fluid as it has no lubrication, put a little mixed fuel in the carburetor or in the plug hole if you prefer.

Mark
 
I don't think coil problems are common with the 600 series saws, but not impossible. I would look at the oil pump and carb/fuel line/fuel filter first.

I had similar smoking issues with my 610. I took off the oil pump and ran some kerosene through it to clean the internals. I manually ran the kero through the inlet port while working the manual then the auto pump. This stopped the smoking. Or just buy a new pump to put on it. You could also try pulling the spark plug, hold the saw plug hole down and pull the recoil several times to try and clear out some of the oil. This might help stop the plug from fouling so it will start.

Other hard starting issues could be the carb as Mark stated. Give it a good cleaning and maybe put a carb kit in it. A new fuel line and filter would also eliminate a possible issue.

Sent from my SM-S367VL using Tapatalk
 
It ran so well when it started that I would think that the oil on the plug is the major issue, not sure. From past experience, the spark looks a little weak but I'm also looking at it in bright sunlight. It was only used once after purchase so as far as a dirt carb or muffler is not my first priority and the fuel line looks ok, can't see much of it and there were no leaks, the fuel filter looks clean but I'm not sure if the "fuzzy" type element gets swollen? I used old bar oil that was clear and looked too thin, what the highest viscosity oil that can be used? I have some dino 80-90W gear oil that I was going to get rid of, maybe a heavier bar oil would get less into the chamber. I was going to buy whatever the best synthetic bar oil was but I'll hold off on that for now. The smoke didn't bother me but after I stopped it I noticed that the muffler was dripping with oil, that can't be good in the long run. The starting fluid I use says that it does have upper cylinder lube in it so I'm not too worried about it. Is the diaphram in the oil pump available and easy to get to? My problem right now is that I need the 20" bar to get rid of a downed tree.
 
So it sat for a few days without a plug in it and with some starting fluid it started on the 3rd. pull. I couple of things that I noticed, it barely used any oil after an hour and a half of use, looks like what it did use was from me pumping it. The chain seems pretty dull now. If you pull the chain brake kickback handle back the RPM's increase, it starts better/faster if the air filter cover is off, when you just start snugging the plastic nut down the engine sounds like it wants to stall. If you get it running good that only affects it a little. Is it easy to check the diaphram on the oil pump?
 
View attachment 845486
Take a look here for bar oiler adjustment in the owner's manual. Your first post indicates that you have the manual.

No page like that in my manual, no bar oiler adjustment in there either. My "8" section only goes up to 2. and the figures are labeled like "6-1C" not just a number. If the pump is similar the way to turn the screw should be the same, how much of a turn counterclockwise should I start with?
 
The chain brake is off right? It should be snapped all the way back.

Sent from my LM-G820 using Tapatalk
 
Thanks for that manual, it helps, I'll adjust it right now... My manual that's in the OP is different, it has "Timber Bear" "Pro-Mac" 605,610 "Super Pro-Mac" 610 and Power Mac 605-20. My Model # 600134-24 is which of those model names? Some of the photos have a yellow body, some are black w/ yellow covers, I guess what year the model is matters too. Thanks, again.

Adjusted it, works great......left the Tractor Supply bar oil in it, my 80-90W gear oil felt thinner and not tacky at all. It even started this time with Tru-Fuel in it, didn't before, the E3.16 plug started faster than the old DJ8J and the newer fine electrode DJ8J.
 
So it sat for a few days without a plug in it and with some starting fluid it started on the 3rd. pull. I couple of things that I noticed, it barely used any oil after an hour and a half of use, looks like what it did use was from me pumping it. The chain seems pretty dull now. If you pull the chain brake kickback handle back the RPM's increase, it starts better/faster if the air filter cover is off, when you just start snugging the plastic nut down the engine sounds like it wants to stall. If you get it running good that only affects it a little. Is it easy to check the diaphram on the oil pump?
I wouldn't worry about replacing your oil pump diaphragm. If the auto oiler works it should be fine.

Wherever the bar oil is coming from it leaks very slowly. It would take my 600 series saw many months to accumulate enough oil to heavily smoke. Try to start it every so often to clear it out.

Sent from my SM-S367VL using Tapatalk
 
Has anyone tried replacing the "sealing washers" used with the bolts that mount the crank cap, found inside the oil tank, to stop the excessive smoking condition? I wonder if a slow leak here could find its way into the crankcase. I find it hard to believe a newer oil pump could be causing this condition.

Sent from my SM-S367VL using Tapatalk
 
Good question... I snugged down the screws on the top of the pump thinking the same.
I used the saw for about 1-1/2 to 2hrs. and it smoked the whole time, with no breeze either.
 
I also ran into this last weekend with a PM-610 that I got somewhat recently. I did just a little work to it, it ran when I got it. just a new plug (RDJ6? I forget, I got a bunch of different ones to try) and cleaning the whole saw (including the muffler - piston looks great and it makes good compression). Removed the spark arrestor screen, was pretty clogged. But it starts great, however still burbles at full tilt boogie in the cut. It feels too easy to pull start though... that Q-port design must be it. Tried adjusting the H screw in the wood and it didn't clear out. It smoked like hell the whole time. Ran new non-ethanol 91 fuel + stihl HP ultra synthetic at 40:1.

Bar oil seemed to be running fine. I'd give it a pump here and there. But I certainly didn't notice any bar oil starvation going on. Albeit I didn't get to cut too much.

But now I'm wondering if it's bar oil getting in the chamber, because yeah.... it surely kept the bugs away but felt like too much.
 
OBTW, KATO,

yes what you have is a Timber Bear, 55cc engine saw. I have one of those too.... still finishing a few things on it but compresson is good so it should be a runner.Mine is a 60013416

but yours being a Reconditioned one, they may have added the dash number or whatever. Looks clean !

Edit..... it may be an Eager Beaver 3.4 ---- I'm still trying to figure out all these Mac names and numbers!
 
Good question... I snugged down the screws on the top of the pump thinking the same.
I used the saw for about 1-1/2 to 2hrs. and it smoked the whole time, with no breeze either.
 
So now with the Tru-Fuel it didn't run the same, bogs down...when I even start to tighten the plastic air cleaner nut it starts to stall, not sure if it's the pulling on the stud, the sealing of the filter or something else, if I take it off and spray starting fluid directly on the filter it starts the fastest. The auto oiler is still not putting out enough oil, I'll keep adjusting it.
 
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