88 Johnson throttle problems- Engine or control box? HAVE PICTURES! HELP!

[Paulrd27]

Hello Everyone,
Here is a couple pictures that I took today. Don't know much about boat motors so bare with me here.. I have an 88 Johnson 150 V6 that is having throttle issues. As soon as I turn the engine on the revs go really high. Then if I try to go into gear there is a big grinding noise. It's like the choke is all the way up when I start it. Here is a couple pictures of the engine and control box. In the first picture where I have put arrows, that silver link was off. So i reconnected it and still have the same problem. When I hold that black thing all the way back the revs go right down to normal. Also, on the control box, the thing where I have arrows pointing to stays up and doesn't clasp down. When I move it up and down I dont see anything happening on the motor. Is it on the motor, control box or links that I need to change?? I'm sorry, like I said I dont know much about boats.. :facepalm: but any information would be greatly appreciated!

 

[Paulrd27]

Re: 88 Johnson throttle problems- Engine or control box? HAVE PICTURES! HELP!

I can take more pictures?

 

[emdsapmgr]

Re: 88 Johnson throttle problems- Engine or control box? HAVE PICTURES! HELP!

A couple of things. 1. The link arm you mentioned that came off is the spark advance link. If it comes off, the throttle handle is no longer controlling the spark timing at the engine. It is very possible to have a surge of rpm's if this link arm become disconnected. When the engine runs at idle, that link arm should hold the timer base all the way at the rear, as you have shown in picture #1. The rubber at the end of that screw is max timing advance-for wide open throttle operation only. That screw is the one with the nut between the rubber tip and the engine casting gusset. 2. It appears you have a problem with the setup of the throttle cable linkage at the engine end. Perhaps just a simple cable mis-adjustment. I'd remove (unbolt) the throttle cable connection at the engine end. This will relax the engine spark advance arm on the powerhead. The spark advance arm is spring-loaded and should permit the idle screw (also with a rubber end) to move rearward and touch the powerhead. Picture #3. Once the engine linkage is in the idle position, you can observe the cable end you just diisconnected. Likely it now does not exactly meet the stud on the engine. Make sure the throttle handle on the control box is in the middle (neutral) position and the cold-start lever of the control box is in the full down position. You may have to turn the thumbscrew on the cable (in the lower cowling) to align it (move the cable end forward or backward) with the stud. When in neutral you want the rubber tip in picture #3 to be pressed against the block-that's the idle position. You may need to re-adjust the cable a few times to get the spark advance arm to be in the correct idle position.

 

[adriandavidpayne]

Re: 88 Johnson throttle problems- Engine or control box? HAVE PICTURES! HELP!

Here's what mine is doing, any ideas? Johnson GT 150 Timber Base Problem - YouTube