Valve guide seal replacement???

[lowveld]

My circa 1977 YM1300D has plenty of power and starts just fine (about 760 hours--I don't know if meter is correct). However, I get quite a large amounty of blue-white smoke for a few seconds when I pull the throttle lever say from 1,000 rpm to 1,800 rpm--not much of same smoke when idleing, but some. I do not ever get any black smoke--is that an issue?

I have changed valve guide seals on gasoline engines without removing the cylinder hear using compressed air to hold the valves up. I assume that on a Yanmar diesel engine that the procedure would be to have the piston at top dead center and compress the valve spring allowing the valve face to contact the top of the piston. Is this the correct procedure? Also what type of valve spring compressor is most often used to accomplish this procedure on a Yanmar engine, and where do I obtain it; or is better to make a spring compressor tool?

What is a proper range of cylinder compression (in psi) for a Yanmar engine of this age and hours?

I have only owned this 1300D for a few months and have "brought it up to par" by rebuilding the brakes, replacing steering shaft bushing, replacing all the fluids, adjusting steering box, replacing U-joints (quite a bit of milling and cutting in my mini-machine shop) and replacing front axle O-rings and seals along with king-pin bushings. All in all it is a good tractor for its age.

Sincerest Best Regards;

 

[ProdaddyTX]

Some smoke on rapid thottle increase is normal...it's so subjective..."quite a lot" can mean a lot of different things, so I don't want to tell you all is well if it's smoking like a 4 alarm apartment fire.
I don't have compression data for that engine in front of me, but the 3 cyl in a YM1610 calls for "Specified Pressure" at 1000 ft elevation of 568-639 psi, with a lower limit of 426 psi. In other words, below 426 you'll experience hard starting and should overhaul. Reduce these number by 3.6% for every additional 1000' in elevation.
Hope that helps.