The Fordson Tractor Pages Forum

What is your opinion, Major specialists! I have heard that Major's engine starting wouldn't be allowed when decompressor is on? It can damage the valves and push rods when the piston hits the valves. Only an engine turning with crank would be possible?
Difficult to believe if timing and valve clearance are ok!

Hi
You can sometimes get away with it from what a few guys have told me over the years but have seen a few go wrong too. Brian will say never do it. I just bought a super major that was supposed to need a head gasket. It was running on 3 cylinders . on removal of the rocker cover it was found to have a bent push rod on one cylinder and a broken one on the next . on removal of the head it was found that one piston had 4 slots gouged out of the piston crown where it had been spraying hi pressure fuel and not burning it.
They had run it so long I need to change the piston/ and push rods/ I'am also hoping that the crank is not damaged when I get the oil pan off
Long story short the guy that had this one needed a kick in the privates and NO I WOULD NOT USE THE DECOMPRESSOR After finding this I 'am thinking i would lock the levers permanently or cut the end off on any I sell for acreage guys to use so they cant mess the motor up
I hope that answers your Question and ill post pictures of my wreck when I get chance
Regards Robert

The decompressor is only to be used for turning the engine by hand. That is what the Fordson Instruction books say!

Other types of decompressor open extra valves in the cylinders but the Fordson one works on the existing exhaust valves, holding them open. Push rods can jump out of position if the engine turns over too fast when the decompressor is used.

Been there, seen it done, replaced valves, rockers and push rods on engines owned by people who where unbelievers,

Many thanks Robert and Brian for competent answers!