Decompression doing anything?

[Todd8665]

I've had my YM2210D for about two months now. I religiously pull the decompression lever each time I start the tractor, then push it back in once started. My problem is that I can't sense any difference in the engine (sound, idle, smoke color) when the lever is pulled vs. the lever being pushed in. I can open the hood and pull the decompression lever and see the linkage work all the way to the valve cover and everything there seems normal.

Question for anyone with a 2210 or similar 2 cylinder Yanmar. Can you tell when the decompression lever is pulled by the way your engine is running?? I there some other way for me to tell whether or not the decompression level is actually working - eg relieving the pressure. I suppose I could try and find some way to hand crank the engine, but im not sure if that would tell me much.

Thanks

 

[deepNdirt]

Welcome to TBN,

Does the engine actually startup while the decompression lever is open? Mine will not start, after it has turned over for about 5-10 seconds and when I release the lever it does puff some smoke and starts right up,
If yours starts when the lever is applied, then I'd say the decompression valve is remaining closed,
You should be noticing a big difference in the engine speed while turning over when open verses when closed,

 

[winston1]

The compression release holds the exhaust valves from completely closing, therefore no compression. There should be a very noticeable difference in ease and speed of engine turn over when pulled. Your engine should not crank or run when the release is pulled. There is a cam action on ref #39 on this drawing. Yanmar Tractor Parts: HEAD

 

[Todd8665]

Thanks for the reply deepiNdirt and Winston.

Sounds like my decompression is not working because my engine definitely runs with the lever pulled. From Winston's diagram I see a few pins/small bolts along that shaft. I'd imagine that if I lost one or more of them then that would negate any Cam action....

Sigh,,,I really don't want to pull the valve cover, but I have been wondering about my valve clearance too. My valve cover is similar to the diagram in that it also has the small inspection plates? (#44 on diagram). I pull them off and peek inside to see if I can see anything.

 

[clemsonfor]

the lever turns not pulls. i just dont think your linkages are connected. not nessisarily under the valve cover.

It should sound like wooomp wooomp wooomp when it has compression and like wa wa wa wa wa wa wa, when its open. Its a noticeable difference in cranking speed even with a fully charged battery.

Plus like they said its impossible to start it with the lever engaged, as there is no compression

 

[Todd8665]

clemsonfor,

Correct...on my tractor you pull the "knob/cable" which turns the lever at the valve cover. I can see/watch all this take place with the hood open - and/or I can move the lever at the valve cover by hand. Same results...

 

[Scotty Dive]

Just my 2 cents here. On my 2020D - 3cyl, I don't notice a great deal of difference with the decompression lever pulled when the outside temperatures are 60 or better. Mine will actually begin to start while its pulled. I do know that mine is working because once I pulled it while it was running and it eventually dies. Now in the winter when everything is cold and that oil doesn't want to flow - I can really notice the difference.

 

[normde2001]

Just my 2 cents here. On my 2020D - 3cyl, I don't notice a great deal of difference with the decompression lever pulled when the outside temperatures are 60 or better. Mine will actually begin to start while its pulled. I do know that mine is working because once I pulled it while it was running and it eventually dies. Now in the winter when everything is cold and that oil doesn't want to flow - I can really notice the difference.

It needs adjustment. Should not attempt to start, and should immediately lose compression when activated, ( although you should not activate when running).

 

[kenmac]

My 3110 will not start with decomp pulled

 

[Scotty Dive]

Same here. Mine won't start either but it wants to and as soon as I close the decomp it fires up - not as much in very cold weather though