OMC throttle control not working

[cerikson3698]

I have a 84 70 hp rude with OMC controls. I believe my problem is with the controls but not sure. When the throttle is all the way down we only go about 5 mph when we used to do about 30. The throttle will click into idle but not go into idle, then when we pull it back more it just jumps straight into reverse. Sometimes it will idle really really fast and then when we put it in gear it will give a hard jolt but then like I said will only go about 5mph. We can temp fix the problem by pushing the throttle back and forth from froward to reverse. But it always comes back. Do I need to replace the entire control unit and if so would a mercury one be compatable. This is the one I am thinking of purchasing if I need to buy a new one, but not sure if it will work.
Controls


Thanks

 

[cerikson3698]

Re: OMC throttle control not working

clarification to temp fix the prob we push the throtle back and forth when the engine is not started. I also think my last link did not work so I will try it again.

Controls

 

[ezeke]

Re: OMC throttle control not working

You may have a broken cable. Have someone move the throttle arm while you watch the engine to see if the throttle plates are opening.

If the problem is the cable, get the number off the cable at around two feet from the end of the shield and replace it.

 

[jtexas]

Re: OMC throttle control not working

First, a warning. Don't shift it into gear if its idling at over 1500 RPMs, at the risk of an expensive gearcase rebuild.

If you really want a new control box, you'll need to get OMC compatible with your model. But the old one can be fixed. If the problem is in the control box.

You need to narrow it down to inside the box, or at the other end of the cables.

The gearshift lockout - a lever or button on the bottom of the handle at the top of the shift/throttle control, that you squeeze when it's in neutral if you want to shift into gear - is that still there and working?

Take the cowl off and observe the starboard side of the engine while somebody operates the throttle control. the gearshift cable should move first, then the throttle lever starts moving - first the timer base at the top and then the throttle cam.

 

[cerikson3698]

Re: OMC throttle control not working

Thanks I will try looking at that in the morn when I have some light. The gearshift lockout is there and seems to be working fine. If we have it in gear and I pull it back into neutral I can feel and hear that button lock into neutral but the engine wont always shift with it. If we pull it back further it just skips neutral and goes straight into reverse. Thanks a bunch guys, and thanks for that diagram texas that will be a good thing to have around not knowing much about motors.

 

[cerikson3698]

Re: OMC throttle control not working

and If I did need to replace my control box where would I go to look for one that is compatable to my 70 hp evinrude outboard

 

[Randybeall]

Re: OMC throttle control not working

Before you jump to replace the control box, there are repair parts available for most controls. I had to replace the plastic gear in mine, no big deal. No manual for it but the unit is very simple, just look for the wear on the gears which will let them slip over one another. Usually caused by stiff cables, may be time to replace both throttle and gearshift cable also.
lots of luck for a simple fix.

 

[jtexas]

Re: OMC throttle control not working

Randy's right about repairability of the control box, but note that it's in the factory service manual and also in seloc aftermarket manual (I highly recommend the factory manual). If that in fact turns out to be what's wrong.

 

[Gary H NC]

Re: OMC throttle control not working

If the control itself turns out to be the problem there is a bunch of them on Ebay.

 

[cerikson3698]

Re: OMC throttle control not working

hey guys thanks so much for your advice. I went down to check out if the cables where working correctly. I started up the motor and it idles out of control. I dont want to shift it into gear cause of the waring that texas gave me. Are the cables supposed to move even if the motor is not running the gearshift cable moves but notheing else. Does the motor have to be running to tell or have I just identified my problem, and if you need to put it in gear to check the cables is there any way I can get the motor to idle at the correct rpms. thanks so much guys

 

[Gary H NC]

Re: OMC throttle control not working

Sounds like the throttle cable is broken.
The cam in the picture above with the yellow circle can be turned to slow the motor down to idle.Unhook the throttle cable at the engine first.

 

[cerikson3698]

Re: OMC throttle control not working

where does the throttle cable hook into the engine and once that is disconected do I just order a new one and basically plug that one in and I am all set or am I looking at a project. Is there anything else I can do to make sure it is the cable. I dont know much about motors but want to learn so I can fix this thing myself without spending tons of money on labor. thanks

 

[ezeke]

Re: OMC throttle control not working

The throttle cable begins to work after the throttle arm is moved forward to about thrty degrees from the perpendicular. If you are watching the area of the engine shown in the picture, the throttle lever will move with the cable, or not if the cable is broken.

 

[cerikson3698]

Re: OMC throttle control not working

will the throttle cable move even if the motor is not running? Cause all I see moving when I move the throttle forward (while the motor is not running) is the gear shift cable and nothing else so I guess that means it is broken but still not sure if I need to have the engine running while I do this. Thanks

 

[ezeke]

Re: OMC throttle control not working

When you move the throttle arm forward, it does nothing for the first thirty degrees while the gears fully engage. After that, moving the arm at the control fully forward should open the throttle plates on the carbs to wide open (horizontal) A/K/A WOT.

You may need to move the flywheel to get the gears to engage so that you can get past the 30 degree mark. You certainly do not want to run the engine up with no load, so keep it turned off.

 

[cerikson3698]

Re: OMC throttle control not working

ok so my engine is turned off and I can put the throttle all the way past that 30 degree mark. all I see is the gear shift cable moving and the cam does nothing and I see no other movement so I guess I have a broken throttle cable.

 

[Gary H NC]

Re: OMC throttle control not working

Yes,you should see both of them move.You may want to replace the shift cable while you are at it.They both wear about the same.

 

[ezeke]

Re: OMC throttle control not working

The cables have the part numbers that fit your boat, control and motor stamped on thrm, usually within two feet of the ends. Most cable companies now belong to Teleflex, and iboats is a major dealer in the cables.

I got a better deal on them right here in my own town at Nauset Marine, without the shipping charges and with instructions to bring them back if they did not fit. Once you get the numbers you might want to check locally too.

 

[cerikson3698]

Re: OMC throttle control not working

Thanks so much guys I will search out a new throttle cable and will prob do the shift calbe while I am at it.

 

[jtexas]

Re: OMC throttle control not working

Before ordering parts, I suggest opening the control box; you might need something else in addition to, or maybe instead of cables. Also, did you find where the cables attach to the engine? You'll want to see if there's any broken parts in there, too.

Your control box has a hi-idle lever, lifting it should advance the throttle lever (on the engine) without engaging the gears. Might want to check that out.