Re: Need help 1990 70hp Johnson Pro Series 2 stroke
Scott..... Never race the engine when in neutral. That could set up a runaway engine (seen iti happen) whereas the rpms will continue to increase even if you throw the therottle in the idle position. By the time you figure out how to stop it...... connecting rods will be flying out the side of the engine.
If in gear, the engine will only tuen up (tops) 4000 rpm, either the tachometer is set wrong (should be set on #6), the timing is set wrong, the carburetor butterflies are not opening fully, the prop has excessive pitch, OR something is wrong internally (powerhead).
Cutting back (dropping 2000 rpm) may be that your engine has the S.L.O.W. feature (drops the rpm automatically if the engine gets hot) and that a overheat problem exists, OR a cylinder is losing ignition (spark).
Here's a detailed method of converting to premix.
(VRO Pump Conversion To Straight Fuel Pump)
(J. Reeves)
You can convert the VRO pump into a straight fuel pump, eliminating the oil tank and VRO pump warning system, but retain the overheat warning setup (and fuel restriction warning if so equipped) by doing the following:
1 - Cut and plug the oil line at the engine so that the oil side of the VRO pump will not draw air into its system. Trace the wires from the back of the VRO to its rubber plug (electrical plug) and disconnect it.
2 - Trace the two wires from the oil tank to the engine, disconnect those two wires, then remove them and the oil tank.
3 - Mix the 50/1 oil in the proper amount with whatever quantity fuel you have. Disconnect the fuel line at the engine. Pump the fuel primer bulb until fuel exits that hose with the tint of whatever oil you used. Reconnect the fuel hose.
That's it. If you want to test the heat warning system to ease your mind, have the key in the on position, then ground out the tan heat sensor wire that you'll find protruding from the cylinder head. The warning horn should sound off.
Also, I would like to remove my VRO pump and simply run pre-mixed 50:1 in the gas tank. Is there a simple way of doing this / a write up on what I need to plug / address when I remove the VRO.
Also, I changed the factory fuel lines since the hoses looked really old but now my straight hoses are not routed very well, seem to kink easy. If I get rid of the VRO, I will have more room to route my hoses correctly, any help would be appreciated