I have a tohatsu m140a, 1989, it ran fast and hard last year, till I hit ground and ruined my lower unit, replaced that lower unit this month (july 2006) Went to run it and acts like it wants to go, for the first 1500-2000 rpms. It picks up speed and the engine revs, then suddenly around 2000-2500 it over revs shooting to 3500-4000 rpms and I loose all thrust and keep a cruising speed around 10-15 mph. I can back it back down to 1500-2000 rpm and run all day. I checked the water sensor, the oil level sensor and the overheat sensor as described in the shop manual trouble shooting, with no improvement on results. The last thing the book says to change is the CDI unit. Thats a $500 part for my motor and I wanted to get a second opinion before shelling out that money.
