old Mac help ???

[mackdallen]

All of the 740/840 saws were stamped with both numbers, as they both used the same engine block. Only the 795 895, and 797 saws were equipped with DSP, does yours have it?
This information and much more good stuff can be found in the Mac sticky.

dsp = ?

 

[ethar]

Decompression release valve

 

[mackdallen]

no, no decompression valve. i prefer snaping starter ropes anyways

 

[heimannm]

At 99 cc a 740 in good condition will pull a longer bar like 28 or 32" pretty nicely, all depends on the kind ot wood you intend to cut. Very little anti-vibe on that saw so hours in a milling operation could get you white knuckles. There are a lot of longer bar options for a saw like that as all the large frame McCulloch saws used the same bar pattern, check e-bay and you can find many choices including NOS bars up to 38".

A lot of guys like to run 3/8 chain including LP for milling,thinner kerf means less work and less waste but you will find limited options for longer 3/8 sprocket nose bars in the large mount, that much torque means .404 chain is better.

DSP actually stands for De Stroking Port, the manually operated poppet valve on the 795 and 797 saws as well as other models like the CP 70 and CP125, DSP 3-10 etc. was a McCulloch exclusive.

My 740 is one saw in particular that likes to bite when starting, take a firm grip on the starter and pull like you mean it.

Mark

 

[heimannm]

I can't seem to edit from the Kindle, I should have added that the 740 and 790 did not have the DSP, 795 and 797 did. All but the 797 were available as direct drive (7XX) or gear drive (8XX).

I also have an 840 with a 48" bar, that one is slow in the cut but virtually impossible to stall. I would stick with a 28" bar on a 740 for the kind of wood I cut.

Mark

 

[Warped5]

opcorn:

 

[raycarr]

Where is that old guy with the little yellow truck?