68' johnson 20hp. Throttle doesnt open all the way up...

[Roy Wirebaugh]

The motor runs great, but the tiller handle doesnt open the throttle all the way. I cant move the timing plate anymore and the handle wont turn any further to get to open throttle. What can I do as far as any more adjustments or is something broke? Its a FD 22M.....Thanks, Roy

 

[Vic.S]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

Not sure if you mean just the throttle plate in the carb does not fully open.

If so is the roller on the cam follwer missing #22 HERE

Or if the whole throttle mechanism including the armature plate and throttle cam do not move fully.
If so perhaps the gearing beteen the two parts of the throttle shaft in the tiller handle has slipped a tooth. #92 and #107 (or even #90 and #83 ) HERE

 

[Roy Wirebaugh]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

The roller is there and I have tried to adjust the throttle shaft and its still a no go. Its the whole throttle that doesnt move fully. When I turn the handle to stop, the roller isnt even on the timing cam anymore. When I get to fast on the tiller, the roller is only half way down the timing cam. I cant move the plate any further. There isnt anymore holes to use..

 

[bonz_d]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

Look on the right hand side of the engine, there is a linkage rod that runs verticle to the block. At the bottom end of this rod is a nylon pin that fits into a gear from the tiller. I have been finding that pin worn or broken on a number of 18-35hp motors.

If the tangs are broken or worn it will not advance the throttle completely because of the slop.

 

[Chinewalker]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

Is it in gear when you're trying the throttle? It has a stop built in for restricting how high you can throttle up it in neutral. Also, as noted above, wear to the linkage at the shift handle and the lock-out arm can affect throttle advance.

 

[Roy Wirebaugh]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

I'll look at the nylon pin when I get back home. I wont be back in IL until tomorrow to check it.

 

[Roy Wirebaugh]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

This thing still isnt running and I could really use a picture of the linkages if anybody could post one for me. I have tried to find one and havent had any luck.....Thanks, Roy

 

[bktheking]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

Did you check the lockout? Big bar that runs from the shifter up to the magplate, when you shift into forward the bar moves out of the way of the magplate, you can check this with the motor off.

 

[bktheking]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

#33 is the bar i'm talking about

 

[bonz_d]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

Let's start over.

1. does the twist grip turn all the way? In Nuetral? In Forward?
Use the diagrams linked above by Vic S.

If it does not while in forward check parts 107 and 83 to see if it's out of time and you are running out of teeth on the gears.

If it does turn all the way then look at part 83 (gear). There will be a control lever coming out of the gear. That part is shown in the Powerhead group as part #24. Into that part is part #23, control lever pin. This is the part that I've been finding broken or worn out. Along with part #82 which is a nylon bushing.

Check those things and get back with your findings. Then we'll all go from there.

 

[Roy Wirebaugh]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

Everything checks out ok. The lockout is working correct and the bushing are fine. Is there any way that the flywheel could be rotated? The throttle has full rotation with the tiller handle but it starts way ahead of the throttle cam and stops half way to the end of it. I measured the distance and if I could get it to start on the plate it would run to the end.

 

[bonz_d]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

The timing plate should move before the throttle/carb should open is correct. Then should be completely advanced before the carb gets to wide open.

Sounds like the place to start is at the linkage, go between the linkage at the top of the control lever and work towards the carb. Look for anything that is binding, bent, looks missing.

Any way you could post some pictures of your linkage as it is now?

 

[Roy Wirebaugh]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

I'll try to get a picture posted up tomorrow.

 

[bktheking]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

What do you mean flywheel rotated? They only can go on one way because of the keyway.

I have a 69 20 hp in the garage, I just did a vid of the throttle rotation and setup, I'll post it in a few minutes

 

[bktheking]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

http://www.youtube.com/watch?v=Lpg1uTyYWXg

 

[bonz_d]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

Nice video, great job!

Roy I hope that helps you out. The plastic pin that he points out is the one I've been finding broken/worn. There are 2 tangs on that pin that fit into slots in that gear. Even if just one tang is broken I've found they wont work correctly.

 

[Roy Wirebaugh]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

Thank you so much for the video. I dont have all of the linkage for the throttle. I think that will fix my problem. Now I just need to find the parts....Thanks again, Roy

 

[Roy Wirebaugh]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

After pausing the video, I dont think this will fix my problem. When I turn the tiller back to stop, the roller is way off the throttle cam. It doesnt stop at the end of the cam like the video. This is why I was curious if the flywheel could be moved from where its supposed to be. I cant move the cam enough to get it on the roller. The linkages are different on the 68 and 69. I have the correct linkage according to the brp list, so Im back to where I started..

 

[bktheking]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

Then perhaps somebody had it apart and the gear's are no longer in sync. Did you look at the horizontal gear for the plastic piece I mentioned, is yours there or has it broke off, if they break off there will be a lot of play as mentioned.

 

[Roy Wirebaugh]

Re: 68' johnson 20hp. Throttle doesnt open all the way up...

The plastic piece is there.