70 HP JOHNSON IDLES TOO FAST

[musky hunter]

I have a 1990 70 HP Johnson that idles way too fast when in neutral, I have tried to back the carbs off but they are at the lowest setting already and the timing seems to be ok the boat runs mint at all speeds, starts perfect etc But can be tough to get into gear at this high idle speed.. Help Me someone

 

[DJ]

Re: 70 HP JOHNSON IDLES TOO FAST

musky,<br /><br />Take a good look at your control cables. Is one binding?<br /><br />The only other explanation is an air leak on the intake side of the carb's. I'll bet it's a cable problem.

 

[ob]

Re: 70 HP JOHNSON IDLES TOO FAST

djohns19 is dead on.If it's not the cable binding ,the cable trunion may be in need of adjustment.

 

[musky hunter]

Re: 70 HP JOHNSON IDLES TOO FAST

djohns what is the intake side of the carbs<br /><br /> and which are the trunions the dials on the cables at the bottom of the motor..<br /> Sorry guys I am new to this..

 

[ob]

Re: 70 HP JOHNSON IDLES TOO FAST

Muskyhunter ,Remove the engine cover.The trunion nut is the round ribbed edge adjuster on the starboard side near the bottom.There are two .The upper one adjusts the throttle cable and the lower one is the shift cable.Your engine has an idle adjustment screw on the starboard side.This is the unpainted screw with a spring behind it that stops against the throttle lever.Counter clockwise should decrease rpms.

 

[musky hunter]

Re: 70 HP JOHNSON IDLES TOO FAST

OB how much should I decrease tension on the trunion screw dial? And also does each carb have its own idle adjustment screw in the same location on each carb. I played around in the water today with the tension on the trunions and the idle decreased a litle bit, but the tension on the fast idle lever will increase to the point of popping up about 1 inch or so, how tight do I make the trunions, and is there a way to lube the shift lever itself, it seems to get tight and difficult to move. Thanks for your patience

 

[DJ]

Re: 70 HP JOHNSON IDLES TOO FAST

musky,<br /><br />If the warm up lever handle wants to "pop up". The "tension wheel" is too tight. Keep backing it off.<br /><br />The carbs. work together. They have a gang linkage that synchronizes them.

 

[ob]

Re: 70 HP JOHNSON IDLES TOO FAST

Musky , Only one idle speed screw for all carbs.<br /><br />If you are in question as to the tension on the trunion adjusters,place the engine controls in neutral.Disconnect the throttle cable from the throttle lever.Also remove the shift cable pin and disconnect it from the shift arm linkage.Once shift cable pin is removed insure the shift arm is in the neutral position and note the alignment of the shift cable pin hole to the hole in the shift arm link.Adjust trunion screw until this hole is perfectly aligned.Insert cable pin.<br /> <br /> To adjust the throttle cable once removed,insure that the carb linkage roller is in line on center with the scribe line on the fiber throttle cam and just touching.Adjust the trunion in the same method until throttle cable end hole is aligned with throttle lever hole or stud and reconnect.<br /><br />This should place your cables in an unbinding position.Fine adjustments may be necessary.While the cables are disconnected actuate controls through a wide throttle range and insure freedom of movement with both cables before the above procedure is performed.If there is any detectable binding of movement ,one or both of the cables are in need of lube or replacement or the problem lies within your throttle control box.