Mall Model 7 Help Requested

[GMieske]

We just acquired a Mall 7 not a Mall 7H. Do I file the chain with a straight file? What weight oil do I put in the oil reservoir under the gas tank? Does this lube the chain or the gear box? Thank you!

[Andrew Mackey]

The transmission case lubes the gearset only. it takes a very lightweight grease, like that used in outboard lower end gears. The chain is manually lubed with SAE 30 motor oil. This info is taken directly from Mall operations manual, printed 2/1948
Andrew

[GMieske]

Thank you. Does it say how to sharpen the chain? Do I use a straight file?

[GADavis]

This is probably going to need a 1/4" file on that big of a chain. Probably a 1/2' pitch chain. lower the drags,( or commonly known as depth gauges now) at .035 to .050 for normal cutting. Some of the older Malls had left hand threaded flywheel nuts with a self pulling arrangement and had a nasty habit of ocassionally backfireing and sending the flywheel off through the woods and that really made the logger cuss. Was working in the saw business at the end of the 2 man saw era.

[Andrew Mackey]

First, what chain is on your saw?
My manual shows 2 different types, a Kerf style and a chisel style (similar to what modern saws use), as OEM mounted.

The kerf type looks like it says, instead of the modern style chain, it looks like just vertical straight blades bent slightly right and left. If this is the chain you have, the individual teeth are purposely made that way. There are actually 2 sets of teeth on this chain,There are right hand cutters (#28492), Left hand cutters(#28493), Right hand Rakers (#19782) and Left hand Rakers (#18783). The cutting teeth are mounted on the outside links of the chain, the rakers are mounted in the center. The manual also mentions that older chains also had straight rakers in the center link set. The cutter teeth do the actual cutting, and the rakers clear the shavings from the cut area, All teeth are sharpened by hand with a flat tapered file.
The cutter teeth (outside R & L)are filed at a 30 degree angle, with the leading (long ) edge toward the outside (away from the center of the chain) of the tooth. The filed surface must also angle from top to bottom 10 degrees, with the top being the long side (leading the base of the tooth). The tops of all teeth are also angled 10 degrees toward the rear, that is the front of the tooth is the high point. If your chain has straight rakers, they are filed in only 2 dimensions - front at the 10 degrees of rake,straight across and top at the 10 degrees of lead. Top is front high and forward.

The raker teeth (the ones mounted in the center) are filed in the same manor as the cutters, but at only 15 degrees of angle on the leading edge instead of the 30 the cutters use. If you look at the height of the teeth, the outside cutters are also 1/64th of an inch higher than the raker teeth.

The chisel style (looks like a modern chain) is also filed with a flat file. The angles for filing are 35 to 38 degrees from parallel to the chain, leading edge toward the outside, and 28 to 30 degrees from vertical, top leading the bottom. The guide edge which leads the cutting edge, should be 1/64th of an inch lower than the cutting edge itself, but if you are cutting softwoods like spruce and pine, the lead depth may be increased to up to 1/16". All guage guides must be of the same height in order to keep an individual tooth from gouging and possibly breaking the chain. DO NOT sharpen these chains with a rotary file or grinder - they are not meant to be sharpened this way, and if it is done, possible tooth breakage may result!

Your saw uses a 12:1 fuel/oil ratio, SEA 30 NON Detergent oil is recommended. DO NOT cut the oil ratio to 16:1, that ratio does not meet the engine lube requirements. Also, do not use the synthetid lubes, as they will not perform well in this low speed engine.

WARNING DO NOT RUN THIS ENGINE AT FULL THROTTLE WITH NO LOAD This engine has no governor, and the engine WILL break up catastrophicly if run in this way for any length of time. This warning is taken directly fron the Mall manual

The transmission is filled to the base of the fill plug opening, with a light weight grease such as used in marine outboard engine lower end gear sets. A good marine engine shop should have this grease, IT IS NOT HYPOID OIL!
The manual does not specify the amount needed, but the grease was sold in 13 ounce tubes.

Point gap: .018", Plug: Champion C-7 - gap.025" , Timing set at 30degrees BTC. Engine rated at 7HP@4800 RPM. NOTE THIS ENGINE HAS NO GOVERNOR!

Andrew