Re: Could be lots of 2 strokes for sale here!
You are correct bruceb, it is definitely part of the issue.
I don't know much about marine test standards and limits, but with heavy-duty truck and bus engines we must run an initial emission test and then a 2000 hour, accelerated durability test with the first model of any significantly different engine technology. The 2000 hour test is pretty severe, it goes something like idle, then full RPM no load, then full RPM and full power, and then peak torque RPM, and then repeats; over and over for 2000 hours. Only break is for scheduled maintenance, oil changes, valve adjustment etc. This is supposed to simulate 190,000 miles, and the engineers sweat out the possibility of any failures that may void the test.
After the accelerated durability test is complete, the engine is retested with the same test cycle as the initial test. The difference (deterioration) between the 1st and 2nd emissions tests is tallied and called a deterioration factor (DF), this difference is then applied to any new model that is certified with the same basic technology i.e. 2 stroke carb, 2 stroke DI, 4 stroke carb, 4 stroke EFI would probably all require a separate DF. If I remember correctly, you end up with an individual DF for NOx, CO, Hydrocarbons and Particulates (PM) and this amount must be added to any future test results for each of those constituents.
A company may be able to go 10 years or more with the same DF(s) if it can be argued that the basic technology has not changed much. This testing is extremely expensive and must be performed by a certified independent facility, so there is a benefit to making a really good argument AND not making wholesale changes to technology. I am guessing there is something similar in the latest marine regs too . . .
keep me posted .will watch for the adds ......
