9.9 Evinrude Issues

I purchased a 1979 Evinrude 9.9 2-stroke outboard, model 10924B, serial#06656 this summer. I replaced the plugs, changed the gear oil, ran it with new fuel. Started on the second pull, accelerates and planes nicely. That was earlier in the summer.

Now, out of the blue, something odd is happening...I started it right up a few weeks ago - but it wouldn't accelerate. I turn the throttle and it just either bogs out or stays at a very low speed, RPM. I put in new plugs (the newer Champion version of what the outboard recommends, as they do not make the older ones) and it has plenty of oil/gas, etc. I had a compression test done and it all checked out fine.

Additionally, I cleaned the carb (which was dirty), replaced the fuel pump (since the diaphragms were all torn) and still am having the issue. When I run it forward or in neutral in the tank, it seems to run fine. It's just when I get it out on the water, I put it into forward, accelerate, and it won't - it might for 2 or 3 seconds then just bog down to about quarter speed, then accelerate, then bog down again.

What would caused this motor to all of the sudden just not be able to accelerate and get gas? The gas bulb is firm when running and the lines/hoses are all secure. Thoughts??? Am I losing my mind? Could it be the gas tank, the line? No idea guys, no idea.

I've included a link of a youtube video showing you the issue...towards the end of the video when I am going real slow the throttle is actually gunned all the way.

http://youtu.be/mSVgryG4FdE

Thanks for any help!

Re: 9.9 Evinrude Issues

check spark on both cyls, they run pretty good in a barrel on one cyl, start great too. you might even have a coil breaking down when it gets warm. a carb kit, and complete cleaning.....welch plugs out, soak, clean all orifices and reassemble is a good general maintenance plan also. ( do you use ethanol added fuel?....it has caused issues with fuel lines. but check one thing at a time)

Re: 9.9 Evinrude Issues

nwcove said:

check spark on both cyls, they run pretty good in a barrel on one cyl, start great too. you might even have a coil breaking down when it gets warm. a carb kit, and complete cleaning.....welch plugs out, soak, clean all orifices and reassemble is a good general maintenance plan also. ( do you use ethanol added fuel?....it has caused issues with fuel lines. but check one thing at a time)

Click to expand...

I have used ethanol...which makes me wonder if that could the cause, since it was running perfectly then out of the blue was running crappy...Maybe the previous owner used fuel conditioner...I have not, but could ethanol cause it to run that poorly?

Re: 9.9 Evinrude Issues

Check your twist grip throttle gear teeth engagement. I will bet that somewhere along the line, you raised the tiller handle AND changed the throttle setting while it was up. This will usually allow the gear cogs to become mismatched. These gears have to be meshed properly or you can not get proper throttle timing. This model is designed to disengage IF the tiller handle is raised, apparently so that IF you attach remote controls, with the handle up & back you are not also twisting the twist grip (lessening the reistance).

Look at the gears, both have one space that is double of the single teeth. These double spaces need to mesh together.

Re: 9.9 Evinrude Issues

I did raise the throttle handle all the way back right before I was having troubles...I actually put some new grease on the teeth fittings...I wonder if it could be something as simple as that...

Re: 9.9 Evinrude Issues

Check out what the machinist has indicated. I am a little sceptical because you say that it bogs down, then accelerates and then bogs down again. This is typical of a cylinder cutting in and cutting out. An intermittant cylinder is usually a function of some ignition (spark) problem.

What are the new spark plugs that you are using?