Re: 1974 johnson stinger2 trouble( 70hp)
Leafs.... I'm assuming that you have the proper propeller installed on that engine to be compatible with your boat.<br /><br />With the boat on a trailer, look at the rig from the side. With the engine in the running position, the cavitation plate (the plate just above the prop) should be approximately 1" below the keel (bottom of the boat) at the transom, and it should be on a parallel with the keel. That is, the line of sight of the bottom of the boat should be the same as the cavitation plate with the plate being 1" lower.<br /><br />If the above is as it should be, it would be a good idea to check the engine out as follows.<br /><br />(General Engine Checks)<br /><br />First, check the compression. It should be approx 100+ psi and even on all cylinders. On some V/6 looper engines, the starter bendix will kick out if all of the spark plugs are removed. If this takes place, leave the spark plugs in, excepting the cylinder you're checking of course.<br /><br />NOTE..... If leaving the spark plugs in while you're checking the compression (V/6 Loopers), make sure that the ignition key is in the "OFF" position. You do not want that engine to start while you're doing that test. <br /><br />Next, with the s/plugs removed, check the spark. It should jump a 7/16" gap (1973 to present) with a strong blue flame on all cylinders. (The s/plugs must be removed in order to obtain the highest rpm available).<br /><br />Check the continuity of the ignition coils. Remove the primary orange wire from whatever it's connected to. It may be connected to a powerpack screw type terminal, a rubber plug connector, or it may simply plug onto a small boss terminal of the coil itself.<br /><br />Connect the black lead of a ohm meter to the spark plug boot terminal, then with the red ohm meter lead, touch the ground of the coil or the powerhead itself if the coil is still installed.<br /><br />Then touch (still with the red lead) the orange wire if it's attached to the coil, or if it's not attached, touch the primary stud of the coil. You should get a reading on both touches (contacts). If not, check the spring terminal inside the rubber boots of the spark plug wire. Poor or no continuity of a coil is one reason for s/plug fouling.<br /> <br />When removing the spark plugs, make a note of which s/plug came from what cylinder. They should all look alike, but if not, that difference should lead a mechanic in a certain direction.<br /><br />If the engine has been sitting for any length of time (a month or more), there's a very good possibility that the carburetor(s) are somewhat fouled/clogged/gummed. If so, they'll require removing, cleaning, and rebuilding.<br /> <br />Remove the carburetor face plate. Observe the carburetor(s) while you pump the fuel primer bulb. If fuel flows out of the carburetor(s), they will require removing, cleaning, and rebuilding.
