For those who want to experiment with variable timing: There are several sellers present on Ebay selling plungers pump for the Yanmar clones.
These are replacement pumps that probably could be machined in an effort to make a variable injection timing pump.
Model number "186" is the search word for these motors (i.e. the 406ccm). Further Internet searches also name the pump as "Element Pump" or "M117".
Prices on Ebay are $88-$93. But delivered from China the price is as low as $3-$7 each when sold as lots, at the moment no minimum numbers mentioned.
Interestingly, I've noticed that the pumps and injectors listed reportedly fit the L100V engine, which is the Tier II compliant version from Yanmar. It has been bumped to 435 cc's but derated to 9.1 HP. Makes me wonder what they have done to the injection system to get it EPA compliant.
It should be noted that they're listed as "fitting" the L100V engine, but are the same part number as the pump sold for the 186 engine. Thus, it may only "fit" the L100V engine while being the "old" 186 pump. Perhaps a quick email to the seller would clear this up.
I would gather the LA100V would have a marked decrease in fuel delivery, it seems compression etc is the same.
It would be interesting to see the two delivery pumps and injectors dismantled to see if their is any marked difference in plunger sizes and nozzle design. Id think not, but may be wrong
I'd guess that the lower emission engine would have the timing set a bit more retarded to reduce NOx levels. This would also reduce power/fuel economy.
I can get yanmar injection pumps
Yanmar air cooled
Single cylinder
Engine type: YDLL , YPFE-M
Plunger Element O.D 6mm.
Delivery valve O.D 4.1mm
and
Yanmar air cooled
Single cylinder
Engine type: YDLL . YPFE-M
