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1976 Evinrude 135 acceleration problem

CTs boat ?

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I have a 1976 Evinrude 135 hp that often chokes out when I try to accelerate. It will kill if I don't back off. Once I back off the throttle it will chug along at 6 - 7 mph until it clears out and starts to accelerate on its own. Usually 10 to 20 seconds. Very frustrating.

I have put new plugs in it, the compression is great in all cylinders and the fuel is not old.

I think it may have something to do with the choke sticking.
 
Compression good,next step is an open air gap spark test before fuel diagnostics, have you visually checked choke operation? Have you tried pumping fuel primer bulb while this issue occurs? it's possible she's running lean, when old plugs were pulled,what were their condition,carbon fouled,tan in color,super white"steam cleaned"? A little more history on your setup would help. Is this a new problem? Ongoing issue? First time out? When was the last time carbs were removed,disassembled,and thoroughly soaked,and cleaned?
 
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Check for a sticky timer base / spark advance. If it sticks, the carbs will open before the spark advances and it will most likely conk out.
 
[h=1]1976 Evinrude 135 hp 135643G[/h]Thank you for your reply. I had it checked out by a mechanic 1.5 years ago. He said it was running strong, put new plugs in it and fired it right up, but when I took it to the lake the a month later the problem persisted. It has been doing it for a number of years now. Not sure on the condition of the plugs, but do know he changed them to a gap type from a flat head with a pin. Not sure if a carb job was done.
 
[h=1]1976 Evinrude 135 hp 135643G[/h]Thanks for your reply, but how do you check for a sticky base? Would doing a carb job help solve a sticky base problem?
 
Thanks for your reply. It seems to run just fine when I first start it up. The acceleration is just fine until I stop and turn off the motor and then restart within a few minutes. That is when it chugs down. Would running it for a while cause the spark to change because it gets hot?
 
Lots of possibilities/guesses. But to check for a sticky timer base, disconnect the throttle cable from the motor, then using your fingers where the cable was attached, move the lever fore and aft. The long lever sticking upward is what moves the timer base. That lever is moved by a spring, so it can lag if the spring can't overcome the stickyness.
 
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