Please help - I have a 28 ft pontoon boat with a 1990 70HP Johnson Pro Series 3 Cylinder Two Stroke Engine.
Back Ground - In spring, I turned the throttle cable round knob to "lower the idle" and I also loosened the bolt stop (boat with spring) on the throttle cable linkage. My adjustments did lower the idle and also made my engine start really quick once warm where as before, I would have to crank and crank along with using ether to start. Bottom line is that I think my "adjustments" messed with the timing of the boat.
I spent 4 hours today trying to set the idle properly as well as set the inital timing to 4 atdc. I have an owner's manual for the johnson engine, but the instructions are so so since they state to set the idle wtih the screw at the top and horizontal below the flywheel where as mine has an adjustable cam linkage.
Ensuring the throttle plates are closed - I followed the procedure and made sure my throttle plates are fully closed.
Setting the initial timing - I disconnected the throttle linkage. I first tried adust using the adjustable cam linkage with the thumb screw since I do not have an adjustable screw below my flywheel but I realized that the cam bracket that this is connected to will move and it does not move my timing which is below the flywheel. The only way to adjust the timing by itself is the turn the screw with a spring as show in the picture below.
The next step I did was to set the throttle plates to the cam plate. I did this by moving the center carbs screw and locking it down when it was lined up with the mark on the cam plate.
After all my adjustments, the problem I have with the motor is that it will idle at 1200 rpm (not in gear), and will rev up just fine, but once you put it in gear, the motor will not rev up, it just falls on it's face and you have NO power. Any help would be greatly appreciated.
Again, my goal was to do the following; set the idle speed (I see no adjustment in this, no such thing as an "idle screw" like I am used to) and set the idle timing while in gear. Now I did the idle timing while in gear but attached to my dock. The manual says to "drive" the boat to check it but that would be a heck of a ride on the back of my toon since the motor is tucked under the rear deck.
Thanks again for any help you guys / women can offer.
SAS
Back Ground - In spring, I turned the throttle cable round knob to "lower the idle" and I also loosened the bolt stop (boat with spring) on the throttle cable linkage. My adjustments did lower the idle and also made my engine start really quick once warm where as before, I would have to crank and crank along with using ether to start. Bottom line is that I think my "adjustments" messed with the timing of the boat.
I spent 4 hours today trying to set the idle properly as well as set the inital timing to 4 atdc. I have an owner's manual for the johnson engine, but the instructions are so so since they state to set the idle wtih the screw at the top and horizontal below the flywheel where as mine has an adjustable cam linkage.
Ensuring the throttle plates are closed - I followed the procedure and made sure my throttle plates are fully closed.
Setting the initial timing - I disconnected the throttle linkage. I first tried adust using the adjustable cam linkage with the thumb screw since I do not have an adjustable screw below my flywheel but I realized that the cam bracket that this is connected to will move and it does not move my timing which is below the flywheel. The only way to adjust the timing by itself is the turn the screw with a spring as show in the picture below.
The next step I did was to set the throttle plates to the cam plate. I did this by moving the center carbs screw and locking it down when it was lined up with the mark on the cam plate.
After all my adjustments, the problem I have with the motor is that it will idle at 1200 rpm (not in gear), and will rev up just fine, but once you put it in gear, the motor will not rev up, it just falls on it's face and you have NO power. Any help would be greatly appreciated.
Again, my goal was to do the following; set the idle speed (I see no adjustment in this, no such thing as an "idle screw" like I am used to) and set the idle timing while in gear. Now I did the idle timing while in gear but attached to my dock. The manual says to "drive" the boat to check it but that would be a heck of a ride on the back of my toon since the motor is tucked under the rear deck.
Thanks again for any help you guys / women can offer.
SAS