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Older evinrude 9.9 issue

C

Curry

New member
Hello
i got given an older evinrude 9.9 and I have been trying to figure out a problem I am having. I was hoping to see what you guys think. So I'll get right to the issue. I jump in my boat and I start the engine. It doesn't have a problem starting or idiling. I put it in the forward position and I start to go. I go slowly up to mid throttle and it cruises right along just fine. I go a little bit more to full throttle and it goes for a bit no problem then all of a sudden it starts pulse almost like it is sucking air or something. It will do it for a bit till either it quits or I slow down the speed. I am concerned about this because I can't have it doing this around my cottage because there is some fast water and I really don't want that happening if I'm in the rapids.
Thanks for the help and I look foreword to seeing what people have to say. Thanks
 
Curry said:
Hello
older evinrude 9.9 ..... It doesn't have a problem starting or idiling. I put it in the forward position and I start to go. I go slowly up to mid throttle and it cruises right along just fine. I go a little bit more to full throttle and it goes for a bit no problem then all of a sudden it starts pulse almost like it is sucking air or something. It will do it for a bit till either it quits or I slow down the speed.
Click to expand...
What year of 9.9?
Boobie's right, try pumping the primer bulb when this happens. Does the primer bulb go flat when this happens?
Is there a vent screw on your fuel tank? Maybe you're forming a vacuum.
Can you see if there is a tell-tale stream of water coming out the starboard rear of the engine? I have a '79 and battled similar issues. Mine was getting too hot due to poor water flow. There are a couple of known issues on this engine that will cause water restriction.
 
I pumped the bulb and it just got hard again. I'm not sure of the year. I am getting a good stream of water coming out of the hole
 
Clean and rebuild the carburetor with a kit as needed.

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
 
joereeves said:
Clean and rebuild the carburetor with a kit as needed.

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
Click to expand...



i took the motor to a boat motor mechanic and got the carb done and set up. What else could it be. I replaced the fuel pump, I got the carb re done, I tried switching my tank and hose to see if it was that and it is still doing the same thing. Any thing else you guys can think of. I appreciate the input. It was sitting for a bit. But ya no idea. Could it be in the tiller?
 
I have got the carb re done from a mechanic and he got the settings all set for me. I put a new fuel pump in and I also tried switching tanks and fuel hose over and it's still doing the same thing. What else could it be. . I appreciate the input guys.
thanks
 
Curry said:
I'm not sure of the year.
Click to expand...

A plate should be attached to the outside portion of the port transom bracket that had the model and serial number on it.

Also the aluminum core plug on the powerhead (looks like a quarter sized freeze out plug) may have those numbers on it.

If those numbers exist... what are they?

What happens if you simply start the engine, let it warm up for a minute, then put it in gear and give it full throttle without playing with the throttle at various settings?
 
Last edited:
Hi Curry, as Joe pointed out, it is no doubt a carb issue.
The one thing to keep in mind with older Evinrude/Johnson 9.9 (1974 - 1979 at least) is that many of the past owners felt the need to transform these motors to a 15hp by changing the carb, and often neglected other details (there's more to a carb swap as you can read on Leeroy's rambling and elsewhere) making the motor act crappy and die on FOT.
Since you must take the carb out, make sure to check if it has the original 9.9 (restricted throat) or the 15hp (larger throat), and then take the appropriate steps.
You can clearly see the difference here (9.9 left / 15 right):

mhd4ja.jpg
 
K I will have to check that out. Unfortunately I'm not that mechanically inclined so I will have to get my father who is a mechanic to give me a hand. I will also get that number off of it tonight for you guys. It just seems to die out at full throttle, it has happened once at mid throttle.
thanks guys I will try to get that stuff checked out for you guys tonight.
 
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