Decarbed a '77 55hp Evinrude for the first time.....

[glengold]

I'm not sure if this is normal, I decarbed using the arisol Seafoam. Let the motor warm up and then started spraying the seafoam down the carb throats.

A quick spray into the bottom carb would cause the motor to sputter instantly, and produced a lot of smoke.

The top carb was a different story, I could spray for a long time before the motor would start to sputter.

Anyone else have a similar result?

Also, I'm not sure if the idle is set too high or my tach isn't set up correctly bc it will read close to 2 grand on the hose. The boat originally had a '97 50hp evinrude and I don't know if the setting on the tach is supposed to be the same.

 

[wilde1j]

Re: Decarbed a '77 55hp Evinrude for the first time.....

Idle should be set in gear, in the water ~ 650 to 700 RPM. Most motors will idle considerably higher on the hose, but 2K is likely too high.

Top carb may be running too lean, which could explain the difference. I would be inclined to disassemble and clean.

 

[5150abf]

Re: Decarbed a '77 55hp Evinrude for the first time.....

Start the engine and pull the top plug and see if it makes a difference, you may be running on one cylinder, you cna also squirt a small amount of gas into the carb, if the engine picks up you need a carb rebuild if it dies it is good.

And yes 2000 at idle is too high and you are risking your lower unit, the gears don't like to be jolted which is what you will do going into gear at that high of an rpm.

 

[glengold]

Re: Decarbed a '77 55hp Evinrude for the first time.....

Thanks for the replies, if I remember correctly it idles around a grand when in the water. What is the max RPM for shifting into gear? I'm going to remove the carbs today and see what I find with the top carb.....

What about the tach setting? I did a few searches and found a post saying a '77 2cyl 55hp Evinrude should be set to 10, and the '97 2cyl 50hp is set to 6.

 

[wilde1j]

Re: Decarbed a '77 55hp Evinrude for the first time.....

As I suggested above, idle should be set in gear and in the water. You can't reliably set it on the hose, but 1000 RPM is likely too high in neutral in the water.

 

[glengold]

Re: Decarbed a '77 55hp Evinrude for the first time.....

thanks, I'll have to wait till the weekend to check that. Any idea on the tach setting? I have a feeling it may be lying to me... since I didn't change any setting after swapping from a '97 50hp to a '77 55hp