1983 Evinrude 50HP - Carb to Which Cylinder?

[phipps]

This may sound silly, but which carb goes to which cylinder? I would assume the top goes to the top cylinder and the bottom to the bottom cylinder.

If I put my hand over the top carb the motor dies. If I put it over the bottom one it slows down but doesn't die.

Now if I go and pull the top plug wire it keeps running, but if I pull the bottom it dies.

Seems odd to me. That's why I was wondering if the carbs are actually feeding the opposite cylinder.

 

[Daviet]

Re: 1983 Evinrude 50HP - Carb to Which Cylinder?

Top to top, bottom to bottom.
Are you having an idle problem? Have you checked compression on both cylinders? Have good spark on both cylinders?

 

[phipps]

Re: 1983 Evinrude 50HP - Carb to Which Cylinder?

The motor starts right up and idles great. It won't top out higher than about 3800rpm at WOT but I'm pretty sure that's a prop issue. The compression is 120 on both cylinders. I have good spark across 1/2" on both cylinders.

A couple weeks ago I had the boat out and it wasn't running right at slow speeds (after running great and then sitting for a few minutes) so I pulled the bottom plug wire and motor died immediately. I pulled the top plug wire and it kept running, although slower, and the coil was arcing against the block. I brought the boat home and have a new coil on the way.

I rebuilt the carbs and replaced all the fuel lines a few weeks ago so I decided to give the motor a good looking over and noticed the small section of fuel line running to the top carb was kinked so I replaced both 90deg sections of hose with 90deg fittings to avoid kinking. I did that today and thought I'd see how the motor reacted to covering the carbs. That's when I noticed the top seems to have more vacuum and kills the motor if covered. I just thought that seemed odd when pulling the plug wire to the top cylinder doesn't kill the motor.

Hopefully the new coil gets here in the next day or so and I'll see what happens.

I may be "creating" an issue where there isn't one. Would it be "normal" for one cylinder to work harder than the other?

 

[Daviet]

Re: 1983 Evinrude 50HP - Carb to Which Cylinder?

In a perfect world both cylinders would be the same.
When you cleaned your carbs did you remove the orifice in the bottom of the bowel and make sure they were not restricted or plugged?

 

[phipps]

Re: 1983 Evinrude 50HP - Carb to Which Cylinder?

In a perfect world both cylinders would be the same.
When you cleaned your carbs did you remove the orifice in the bottom of the bowel and make sure they were not restricted or plugged?

Yes, I pulled all the jets and cleaned them with carb cleaner and air.

 

[boobie]

Re: 1983 Evinrude 50HP - Carb to Which Cylinder?

Sounds like probs on the top cyl.