1981 9.9 Throttle questions.

[soup1279]

Howdy,

I recently upgraded my 1984 4HP 2 stroke to a 1981 9.9HP 2 stroke model E10RCID. It looks like it's been well maintained and works well as in starts up every time and idles smoothly.

I have some questions regarding the throttle. It seems like I have no real middle ground on the throttle or it's very hard to find it. It putts around nicely but when I want to throttle it up it seems like it goes slow slow slow slow slow ok FAST!

I'll try to explain this the best I can. Please forgive me if I'm not explaining myself correctly.

When turning the throttle handle to give it a bit more go it seems like the slow/idle setting takes up 60% or more of the throttle movement. As in I have to turn the handle a great deal to get it to go more than idle speed. I'll have a very small area of ok speed which is right near the end of the throttle movement then it gets into almost WOT at which point is at the very end of the throttle and it gets very hard to turn.

Is this normal or should the increases in power be gradual with the turning of the handle (which I think it should be)

If this is not normal is there an adjustment of some sort that needs to be made to the throttle?

The other thing I noticed is that after I have it at WOT for a little bit to get up river and slow down back to idle it'll pop a couple of times almost like a back fire but not nearly as loud. It'll only do it one or two times and only after having it at WOT

Any help would be greatly appreciated.
Thanks,
Anthony

 

[OptsyEagle]

Re: 1981 9.9 Throttle questions.

The first thing I would want to observe is the thottle cam movement and position in relation to your carburetor cam follower.

You don't need to start your motor for this. If you look at the throttle movement you will notice that as you turn the throttle, a cam plate touches the cam follower (plastic little round piece connected to your carburetor throttle butterfly). That cam plate is what is controlling your carb and throttle level. First, does the plate contact the cam follower when the arrow is in the middle of the little plastic round piece (cam follower). It should be in the middle of that piece just as it touches the cam. This synchonizes your carb to your timing plate.

In my observation, I would want to see if this jump in throttle is mechanical and coming from a jump in the follower cam movement. If not then it is more internal, either in your carb or in your ignition (spark). Let us know what you see.

 

[soup1279]

Re: 1981 9.9 Throttle questions.

Thanks, I'll check it when I get home tonight.

 

[Rick.]

Re: 1981 9.9 Throttle questions.

Certainly agree with above. Good reasoning. I would only add the gear throttle mechanism or these older 9.9 and 15's is horrible and there is a world of play in each of the linkages and added all together well it's just a bad deal. Not that I don't love these old motors, I do but I'm sure part of your problem is with the loosy goosy mess I am talking about. After a while you learn to deal with it or you can tighten it up a bit with home made washers and such. Have a look at this link for a very informative 9.9 and 15 repair tutorial. A must read. Best of luck. Rick.
http://www.sschapterpsa.com/ramblings/Ramblings.html

 

[soup1279]

Re: 1981 9.9 Throttle questions.

The first thing I would want to observe is the thottle cam movement and position in relation to your carburetor cam follower.

You don't need to start your motor for this. If you look at the throttle movement you will notice that as you turn the throttle, a cam plate touches the cam follower (plastic little round piece connected to your carburetor throttle butterfly). That cam plate is what is controlling your carb and throttle level. First, does the plate contact the cam follower when the arrow is in the middle of the little plastic round piece (cam follower). It should be in the middle of that piece just as it touches the cam. This synchonizes your carb to your timing plate.

In my observation, I would want to see if this jump in throttle is mechanical and coming from a jump in the follower cam movement. If not then it is more internal, either in your carb or in your ignition (spark). Let us know what you see.

Thanks, everything seems to be as you say it should be. I did notice something I hadn't noticed before. This motor was painted as it was from a duck hunting boat. I didn't realize there were levels on the throttle. I could never see them before it says Slow Shift Start and Fast. The area of sluggish response is between start and slow while the area that seems to have little middle ground is on the fast side.

When I get to the fast side there is a definitive click like it crossed a barrier. It could also be seen when checking the information you mentioned above. It gets to the point where the slow section ends and you need a little more force to get it to click over to the fast side. Each side of the "click" turns smoothly. So that part seems to be ok.


I hope I made sense and am not just rambling....

 

[OptsyEagle]

Re: 1981 9.9 Throttle questions.

So are you saying that you can feel the jump of the throttle even when you are just turning it without the motor running? That would indicate something mechanical in the throttle mechanisms.

Does this jump make the carb butterfly jump open as well? The cam follower would probably be moving with it as well and if that was the case you should be able to see what would be causing it.

Just so you know the throttle mechanism. The throttle twist grip rotates a plate under the armature plate called the timing plate. This timing plate makes adjustments to the spark timing to fire at the proper time depending on the throttle level. They do this by having throttle cam move the cam follower which opens and closes the throttle butterfy of your carburetor. It is usually a pretty smooth movement perhaps something is catching or broken.

 

[soup1279]

Re: 1981 9.9 Throttle questions.

Yes, all this was done with the motor off. Just popped the hood and watched the parts.

When watching the mechanics you can see it. I'll try to explain it.

As I turn the throttle (from slow to fast) the movement of all parts is smooth until it gets to the "Fast" position on the throttle. When that happens you can feel some sort of stoppage. In order to get past this stoppage you have to apply more turning force to the throttle. At the point when it "breaks" the mechanics jump forward and you can hear a definitive click. At this point the butterfly valve goes from normal operation to almost all open because of the force needed to get it past the stoppage. Now after I get past the click I can move the throttle back and forth to WOT and back to the stoppage area very smoothly.

The scenario repeats when trying to go from Fast to Slow on the throttle as well. Same stoppage, same click just moving the other direction.

I'll try and take a look at it tomorrow night after work. I ran out of time this evening to really mess with it.