Re: 95 SportJet 120 OE109817 How to add TACH?
The installation manual says to run the purple wire on the instrument harness to power the tach, the black goes to the ground, and the gray goes to the sensing terminal on the tach. This makes sense because the gray wire does come directly off the regulator. As to the full throttle problem, it could be almost anything. All you can do is eliminate issues, until you find the most likely culprit. Trouble shooting the ignition system is going to point to coil, spark plug or spark advance problems.<br /><br />Look for (quoting manual) air leaks in the fuel line or fuel pump, restricted fuel filter, chipped, cracked or broken reed valves or a choke/throttle valve that operates improperly. Check ignition timing adjustment. Also a piston or cylinder that is galling, incorrect pistion clearance or a worn/sticky piston ring may be responsible. Look for loose bolts, defective gaskets or leaking mating surfaces on the cylinder head, cylinder or crankcase. Also check the crankshaft seals.
