MAC 610 Maximum High Speed Fuel Adj Setting?

[tbrickner]

Hi Folks,

I wanted to find out if anybody knows the max high speed fuel adjustment RPM setting for an old MAC 610.

The old manual I have says the

Idle speed should be between 1800 to 2000 RPM
Clutch Engagement Speed between 2800 to 3000 RPM
Does any body know the max no load High adjustement? Is it 6000 RPM or higher?

I would like to tack this to make sure I am not running the saw  at too high an RPM or too lean.

I believe the settings should be similar to the MAC Eager Beaver 3.7 or 650 if anyone knows these numbers.

Any comments would be helpful.

Thanks,
Tom

[ladylake]

 
Just guessing I think the no load rpm would be arond 11500 to 12000 on that saw, when cutting around 8000 to 9000 . I'd  just adjust the high so it pulls the best in the cut, then you won't be to lean as they bog easy when too lean.  I ran a 610 for 15 years, it had good power but was heavy.  Steve

[Al_Smith]

Just turn it to where it 4 strokes a tad then leans out and hits power in the log .That's the best you can do .Whatever it is ,is .

A little tip on a Pm 610 ,keep an eye on the screen ,the do plug up . As they get a little age the oilers suck a little bar oil into the crankcase and jamb the muffler tight so keep an eye on it or just remove it if you are so inclined .

[ladylake]

 As Al said watch the muffler screen, they plug up easy . I threw mine out after a couple of months.  Maybe why they had good power, after the screen is gone there's no muffler.   Steve

[Al_Smith]

Oh let me tell you ,a horizontal cylinder Mac  with a gutted muffler will wake the dead . :D I've got a 650 gear drive made in 1966 that will make dogs howl .

[tbrickner]

Thanks Guys for the informaiton.  This site is great1

A few questions if you all don't mind.

1. I am bogging down a little bit and just got a tacometer to see where I am running at on the high end.  I am currently running some husqvarna XP 2 cycle at a 40:1 mix.  I am going to change the mix to 50:1 and see if it a problem with running too lean.  I do get a lot of smoke when I am running it currently at 40:1 mix and it does seem to bog down a lot for a 60 cc saw.  I guess I will check the screen on the muffler also. Thanks for this tip!

Is it horribly loud without the screen on the muffler? 
If I do have a plugged screen should I just take it out? 
Will this give the saw more power like porting a new saw?

2. What oil mix and type of oil do you recommend for this unit?  Will the husqvarna 50:1 work well or any other type of 2 cycle oil?  I am currently using a 93 octain gas mixed with the husqvarna oil at 40:1 which may be leaning out the gas but I can't be sure till i check it with my tachometer and run it through some wood.

Thanks again for all your help.
Tom

[Rocky_J]

Only the most elite and anal-retentive would be able to discern a difference between running 40-1 vs 50-1. It really doesn't matter, run whichever one makes you happy. There isn't enough difference to affect that saw. It's an average saw, you aren't running a hyped up, ultra ported race saw.

Removing a plugged screen will certainly allow the saw to run stronger and cooler, but it won't be 'ported' by a long shot. It will just run the way it's supposed to run (assuming everything else works correctly).

Your Husky XP mix oil is fine. Don't fix what ain't broke. 

[Al_Smith]

 If that old Mac is smoking like it's burning pine knots ,it's not the mix ratio .

That saw uses a diaphragm type impulse operated oil pump . As I said before they get old and stiff and suck bar oil into the crankcase . You can normally find a new pump on E-bay for 20 bucks or less .

The older 10 series saws use a grating over the muffler outlet .For some reason they used a fine screen on the 610 ,Timber bear etc .

[taw6243]

I've got a new free bar for you if you want it. I used to own a pm610.
   231 788 3237

[tbrickner]

Thanks for your help folks!

I just worked on my saw today and cut some 16" diameter oak with it.

The previous owner must have had the same probem with the screen since it was missing the origninal chamber assemly muffler and the screen muffler was replaced with a wide screen.  So I ended up not having a problem with the muffler.

I did find out that I was running a little too rich.  I used my new Fast-Tach tachometer which was well worth the money and found the following:

1. idle ran well at about (2500 to 2700 RPM)
2. Low end (3200-3500 RPM)
3. High end (10500 to 11000RPM)
4. Running with load (6800 to 7800 RPM)

With these adjustment the saw did pull a little better with a 20" bar. 

I also wanted to find out if anyone has measured the temperature of the engine after running it for a while.  I have an infrared thermometer that I  shot at the engine and got somewhere between 190 to 250 deg F. 

Has anyone taken an engine temperature measurment and do my results indicate the saw is running hot, just right, or too cool?



P.S. Thanks also for the offer of the free bar.  I just purchased the 20" bar a month ago so I am good.  Maybe somone else could use it.

Thanks again for all the help.
Tom

[Al_Smith]

Some points of interest on a PM 610 that might be usefull .

Periodically go over all the bolts because this saw will shake them loose . After a hard run give it about 20 seconds or so of cool down period before you shut it off .These things have a tendency to overheat the ignition modul making it inoperative untill it cools down . Once overheated they won't start for love nor money .That one comes from the voice of experiance.

Like any saw they need periodically blown free of chips .On this design they can get packed pretty tight under the cylnder .