I just bought a 9.8 hp Tohatsu 2012. I have a Tiny Tach that I would like to use for the break in. My question is, should I set it for 180,360, or 720 degrees. Any info on how to set this up would be appreciated.
Don't know if 4 strokes fires 2 sparks per revolution as 2 strokes does, begin with 180 and if doesn't read right set it at 360. At idle and neutral your tach should read a minimum of 900 + rpm.
The MFS9.8A3 fires through a siamese coil... so each cylinder fires at the same time... so there is an "extra, wasted" spark on exhaust. Each plug fires every 360 degrees, even though there is only one power stroke per 720 degrees per cylinder. Set the tach as though you had a 2-cylinder 2-stroke.
Fwiw, i soke to tt manufacturer in usa because i was getting erratic readings on my 30 tohatsu , they recommend setting the tach to 180 and parralelling the redwire and connecting to both plug wires. Not sue if that is right but just to keep in mind this is what the tech told me. Actually because it is a siamese coil probably it should be set to 360 and still connected to both plugs as they both fire together anyway. Does that make sense - i think i just confused myself.
Thanks guys. I set it on 360 degrees with 3 wraps around one plug wire and it works great. I called TINYTACH and Steve told me to wrap it around both plug wires as they fire at the same time. I couldn't do that because I used it on another engine and had cut the wire too short to wrap enough times around both wires. Anyway it works great the way it is. Thanks for your help.
ive got mine set to 180, when I had it on 360 it was saying my idle was 2200 which isn't right when i put it to 180 it was 1000-1100. so how can a dual fire coil be set to 360.
No. The 4-strokes fire the same as the 2-strokes, with an "extra" spark on exhaust. Siamese coil, ya know. So set it the same on a 2-cylinder 4-stroke as you would a 2-cylinder 2-stroke.
No. The 4-strokes fire the same as the 2-strokes, with an "extra" spark on exhaust. Siamese coil, ya know. So set it the same on a 2-cylinder 4-stroke as you would a 2-cylinder 2-stroke.
well mine fires on tdc and bdc every stroke (so 2 times each cylinder every 360 degrees or one whole revolution) so I set it at 180 not 360, when i had it at 360 it said the idle was way to high.
