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1976 25 HP Evinrude dies when giving any more throttle than at idle

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code1p36

Regular Contributor
I have a 1976 25 HP electric start or pull start Evinrude that starts up great and runs good at idle and soon as you give it any gas it immediately dies. It is an electric start model but not using any of the controls. Carb is clean, choke is working properly and slow speed needle looks like it is at the correct setting but I am wondering if any of the electric controls could have anything to do with it. I don't have any of the controls or wiring. Any help is appreciated.
 
Re: 25 HP Evinrude dies when giving any more throttle than at idle

Did you make sure that the high speed jet located in the bottom center portion of the float chamber is clean?
 
Re: 25 HP Evinrude dies when giving any more throttle than at idle

Is that the brass tube with several holes in it? If so yes, I made sure that was clean. I try to very slowly throttle it up past idle and it dies right away.
 
Re: 25 HP Evinrude dies when giving any more throttle than at idle

After reading several other forums I notice that people are stating that the throttle roller should be contacting the cam between the points. I just checked my motor and the roller is almost a 1/4" away from where the roller is to where those two etches are at on the cam. It takes quite a bit more throttle before the cam even touches the roller. Do you think that could be my problem? It looks like I need to simply adjust the linkage if that is the case but I want to make sure I am looking at the correct marks because there is another set of marks on the flywheel it looks like which is further up the throttle.
 
Re: 25 HP Evinrude dies when giving any more throttle than at idle

Remove the plug in front of the carb bowl.
Then use a long screw-driver, or better the OMC jet tool, and remove the main jet at the bottom.
The optimum would perhaps be to get a carb kit and rebuild/change all gaskets.
Buy a spray can of carb cleaner and blow through all passages.
An OEM workshop manual is always handy and may save some expensive mistakes!
 
Re: 25 HP Evinrude dies when giving any more throttle than at idle

Maybe also check the synchronization between the carburetor and the timing advance, since in order to function properly,
the two must be "in-sync". Good luck!
 
Re: 25 HP Evinrude dies when giving any more throttle than at idle

RicS1953, how do you check the synchronization? Is it safe to say the roller should start touching the cam where the two marks are at? If that is the case it would be very easy but before I do that I want to make sure that is the correct thing to do. Thanks.
 
Re: 25 HP Evinrude dies when giving any more throttle than at idle

Yes, you're right on it- just loosen the throttle linkage screw on the starboard side and move the roller to make contact with the cam.
 
Re: 25 HP Evinrude dies when giving any more throttle than at idle

code1p36 said:
Is that the brass tube with several holes in it? If so yes, I made sure that was clean. I try to very slowly throttle it up past idle and it dies right away.
Click to expand...

No, that is a high speed nozzle.

There is a screw/bolt at the bottom front portion of the float chamber. In back of that screw/bolt, in the center portion of the float chamber is the brass high speed jet which must be perfectly clean. If even slightly clogged, that will result in the problem you're encountering.
 
Re: 25 HP Evinrude dies when giving any more throttle than at idle

Joe and RicS1953, you guys nailed it, thanks! I removed the carb and cleaned out that area really well as well as the rest of the carb again and it does not die when I give it throttle, it runs pretty good now. When I looked at the roller and cam last night the choke must have been on because the roller touches the cam in the right area now and is farther away with the choke on. Thank you everyone for the help and I can't say enough good things about these forums, I have learned a ton!
 
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