1985 90hp Johnson help...update

[tyndyn]

Okay folks. I earlier posted about a 1985 Johnson that wasn't going more than maybe 10mph. I did a compression test.....120 on 3 112 on 1. I replaced the plugs. I syphoned the old fuel out and put new in. I went back out to the lake. It was still doing the same thing. The engine started right up. It sounded great. But it just didn't seem to get up to full power, and I was probably going around 5-10mph. I found out that the Tach and Speedometer don't work. After dinking around for a couple of hours, I was heading back to the ramp. I adjusted that throttle control....the one that is supposed to control how hard it is to push the throttle. I decided for one more try and I went full throttle....nothing, it did the same thing. Out of frustration, I really pushed the throttle down, to the point that I thought I might break it. The boat picked up speed. It probably took at least 10 seconds or more, but it finally opened up. I am guessing I was going around 40mph. Smooth as heck. As soon as I was going full throttle I did not here one more beep from the overheat alarm all day. After stopping and starting a few times I found that it would only open up if I really cranked down HARD on the throttle, and it always took a looooong time to get going, but once there is was great.<br /><br />Any suggestions? Maybe I can just adjust the throttle cable?<br /><br />Thanks<br />Tyndyn

 

[OBJ]

Re: 1985 90hp Johnson help...update

Pull the cover and watch the linkage and throttle arm as a helper pushes the control to WOT. (you can do this with the engine not running...be sure to spin the prop when it shifts into forward.)<br /><br />As the throttle advances to WOT, you should see the cam engage the roller on the carb linkage and open the carb throttle plates all the way open. If it does not and the control has to be forced more to the open position to do this, the problem either lays in the control cable or the control itself. Or......<br /><br />Check the throttle arm on the engine and linkage by disconnecting the throttle cable and manually going to WOT position. Make sure there is no binding or tight spots during the travel.<br /><br />EDIT: Is the control stiff and hard to push forward? Any binding?

 

[McGR]

Re: 1985 90hp Johnson help...update

You probably also want to check that the timer base is advancing freely. If the bushing/bearing that it rides on is sticky it may be slowing down the amount of time it takes the ignition to reach full advance. Basically, when you "put the pedal to the metal" the throttle plates should be completly open and the timing advanced to the stop.

 

[tyndyn]

Re: 1985 90hp Johnson help...update

The control has almost no resistance until pushed a quarter forward. It then gets harder and harder to push. Also there is almost no acceleration until the final 10 percent or of throttle travel. I will try what you suggested as soon as I can.

 

[tyndyn]

Re: 1985 90hp Johnson help...update

I replaced the throttle cable, the old one was nasty. Went back out to the lake. The new throttle cable actually is a big difference from the old ones, but I still have the problem. When I go full throttle, it accelerates to a certain point, and then levels out. It is not really accellerating enough to get up on plane. Over the course of a minute or more it will eventually go wot. At times it will not go wot for many many minutes, and if I stop the boat for awhile and then go it will eventually go wot again. If my tack was working I could give some rpm info. I guess my next step is going to be to look in my book and find out about the timer base, and fix my tach.<br /><br />I appreciate everyones help<br />Ken