The listing for our new boat stated around 400 hours on the newer Yanmar 3YM20, but the hour meter was broken. I did a quick google search and found a post on the J/109 forum detailing how to fix the problem (https://j109.org/forum/viewtopic.php?f=4&t=205&p=724&hilit=Tachometer#p724). The root of the problem is the sealant in the LCD screen breaking down and shorting out the ribbon cable connecting the screen to the circuit board. The meter still runs, but the tach isn't able to display the info.
Disassembly of the VDO tach w/ hour meter was straight forward and it looked exactly like the article described. I ended up scraping the ribbon cable connecting the LCD to the circuit board away from the contacts. Crap! Now I was big trouble.
Thankfully, there's a company out there for people like me. AKSpeedo.com sells replacement LCD screens with new ribbon cables. I dropped in the new LCD, turned the switch, and the hour meter was showing 486.7. Slightly over the 400 hours in the add, but still very low hours for a 14 year old replacement engine.
Disassembly of the VDO tach w/ hour meter was straight forward and it looked exactly like the article described. I ended up scraping the ribbon cable connecting the LCD to the circuit board away from the contacts. Crap! Now I was big trouble.
Thankfully, there's a company out there for people like me. AKSpeedo.com sells replacement LCD screens with new ribbon cables. I dropped in the new LCD, turned the switch, and the hour meter was showing 486.7. Slightly over the 400 hours in the add, but still very low hours for a 14 year old replacement engine.