super major 5000 ,, decompession lever?

hello all . I went out and started the 5000 today, the battery was of course dead, I think I needs a VR,, IT hasnt been started in a while, it cranked but was hesitant to start, so I pulled the decompression lever up,, started cranking better, but didnt start, I put it back in the down position and it fired off [coinsidence?], down on the lever is off correct, ? I know I have to use it in the winter, but cant remember ..anyway I ran it for about 1/2 hour buzzing some slab wood up, I got a stationary buzzsaw that I got with a 2N I picked up, I run a belt off the pulley and away we go, I also have the woodchipper hooked up to this machine, still using it I have to tell my son, until we get to restore it, thats been 2 year excuse,actually we both like tractors in there work clothes,,, pat

On jap tractor.. for instance.. my yanmar.. it's 'expected' practice to pull the decomp, spint he engine up to get some oil circulated, and then drop it to start.

What does the sm do that makes this not also workable?

Soundguy

On the jap tractors.. you can snatch the decomp full to relieve the valvetrain with no chance of pistons and valves touching. I'm much more comfortable with that kind of engineering tolerance. ( did lucas design those decomp systems on the SM? ) (grin)

Soundguy

The Major 5000 needs a battery of around 128 AH. Most 12 volt batteries vary from 30 AH to around 90 AH so using two together connected + to +, - to - will give you what you need.

(AH = Ampere Hour the way the "ability to work" of a battery is measured, some manufactures nowadays use "cranking amps" over a given time).

It is a big NO-NO to use the decompressor to start in all the Fordson handbooks.

jmixigo wrote: "...the rockers are keyed to an eccentric with woodruff keys"

When I had the rocker assembly taken off from my Major I tried to figure out how the decompressor works. I didn"t dissasemble the assembly any further but I didn"t see any indication of woodruff keys because the rockers turn freely on the shaft. I concluded that the portion on the axle where an individual rocker is placed is slightly offset from the portions where the axle goes through the housing or the five "legs". So it has a resemblance to a crankshaft with very small throws (?). Or it may have a completely different structure but anyway it allows the following to happen: When the axle is turned by the decompressor lever the rockers are lowered a bit (like a piston following a crank) causing the valves to open slightly and this actually tightens the valve push rods not loosens them.

Is this right? I started to suspect myself because of what Majorman wrote. It seems that there is nobody that knows more about this subject than Majorman so I must be wrong. But this leads to another question. How does the decomp lever actually work? Could you shed some light to this matter, Majorman.

Sorry about the long post. I"m the kind of person who wants to know exactly how everything works and I have irritated some people in the past by making a lot of questions.