Can anyone help me with a little problem? I have just returned to boat fishing after 12 years. I have a small 16ft boat with a max design speed of just over 18kph. It is fitted with a 15hp 2 cylinder 4 stroke Yamaha engine (1988/99) which is the max size recommended for the boat. Given average conditions and load etc. I can easily work out my boat's speed using my GPS. No real problem so far. What I would like to find out is
1) What is the max. rev range for the above engine?
2)What revs is it doing at its max design speed of around
18 kph? I have an old Tester/Tune up Analyzer which amongst other things has a Tachometer for 4,6 and eight cylinder engines.
3) Given that 4 cylinders is the lowest setting on my tester, assuming I can find the right wires, I believe that 2 cylinders will give me a reading twice what the tester shows on a 4cylinder setting.
4) Which wires does it need connecting to? When I used to do cars and bikes in the 60's they all had coils and the connections were earth (black meter wire) and live (red meter wire) to the non battery connection on the coil on neg earth vehicles. The reverse applied on the positive earth vehicles.
5) I do not have a wiring diagram and have looked for one on the Internet. Any help apart from buy a bigger boat and engine with a rev counter would be much appreciated.