1975 25 hp Evinrude loud bogging sound at full throttle

Crosby77

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The engine runes perfectly smooth until full throttle which the engine makes a loud bogging sound and im forced to ease off the throttle. Does that mean the engine is running too lean or too rich? or could an adjustment be off somewhere in the carb or could the carb be dirty?
 

AlTn

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Re: 1975 25 hp Evinrude loud bogging sound at full throttle

use a spray bottle with fuel mix and spray it into the carb throat when it's bogging...if the motor picks it, it's too lean..it the bogging worsens, it's probably too rich or you have an ignition problem at wot and are possibly dropping a cylinder
 

Crosby77

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Re: 1975 25 hp Evinrude loud bogging sound at full throttle

How would i be able to tell if im dropping a cylinder and if so how could i prevent it
 

AlTn

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Re: 1975 25 hp Evinrude loud bogging sound at full throttle

pull the plugwire at wot, if no change that cylinder isn't working..if the rpm's drop or the engine quits, that cylinder is firing...obviously use something to pull the plugwire that will prevent your being shocked while doing this... a timing light will also show loss or weakening of spark at wot if you clip it to each wire in turn and observe the strobe...to prevent, you'll have to determine the cause and correct
 

Crosby77

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Re: 1975 25 hp Evinrude loud bogging sound at full throttle

I dont think its the cylinder thats bad. Is it possible that there is obstruction in the high speed jet? or gunk in the carb?
 

boobie

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Re: 1975 25 hp Evinrude loud bogging sound at full throttle

Try the spray bottle trick first.
 

Crosby77

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Re: 1975 25 hp Evinrude loud bogging sound at full throttle

Can this be done in a garbage pal or it has to be done on the water as im moving?
 

Daviet

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Re: 1975 25 hp Evinrude loud bogging sound at full throttle

It has to be done with the boat in the water so you can put a load on it.
 

Crosby77

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Re: 1975 25 hp Evinrude loud bogging sound at full throttle

Is there a specific spray i have to use?
 

Daviet

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Re: 1975 25 hp Evinrude loud bogging sound at full throttle

Use some of you oil/gas mixture out of your tank.
 

Crosby77

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Re: 1975 25 hp Evinrude loud bogging sound at full throttle

Ok so basically if i spray that in the carb when its bogging, if the bogging stops the engine is running too lean?
 

Daviet

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Re: 1975 25 hp Evinrude loud bogging sound at full throttle

Yes, with the boat in the water, throttle wide open, when it boggs down, squirt fuel mixture into carb. If the engine picks up then you have a carb problem. If it tries to flood out, you have an ign problem.
 

Crosby77

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Re: 1975 25 hp Evinrude loud bogging sound at full throttle

ok cool. Im assuming a ignition problem is more serious then a carb problem?
 

Daviet

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Re: 1975 25 hp Evinrude loud bogging sound at full throttle

Maybe, maybe not. You need to find the problem first and then we can help you fix it.
 
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