Tuesday, July 10, 2012

50 hp Evinrude idle rough, bogging and stalling

Boat Idles Rough,bogs and stalls

Boat Stalls and bogs on Accelerate

The issues:

  • It Idles rough.
  • It stalls and bogs when accelerate.
  • Carbs issue.
  • Intake Adjustment Screw
  • Where is Idle adjust screw
  • How to Set Primer System
All mentioned issues stated above will be discussed below,to its best possible way.

1994 evinrude 50 Idles rough?

In this case the compression test needs to be done.On each cylinder you should get approx 115 to 12p Psi.If any of the cylinder shows less Psi,then there lies the problem.Reverse the faulty cylinder to working cylinder ans working cylinder to faulty cylinder and see if the problem reverse.If yes,then you know the cylinder is faulty and replace the cylinder to get the compression right.

If the compression is tested fine and correct on each cylinder then there is a issue with carbs.
The carbs are dirty.
To clean the carbs soak the carbs about half an hour then blew out the jets with choke cleaner,thenput it back together.


When you accelerate the fuel flow runs to carbs.If carbs are serviced and not realigned properly the vehicle will bog down.
Also if the fuel line going to carb is not lined or fitted properly or the fuel line is getting pinched in between and causing low fuel to reach the carbs then it will bog down.


If the carbs were disassemble to service and not realigned properly to its exact position then carbs needs to be re-syncronized to its exact position.
Suppose if one carb throttle plate is open more than the other it will idle rough and cause bogging and stalling. Also these are bad about roller on carb splitting and falling off, the roller that throttle arm pushes against on carb should be the size of  2 pencil and if smaller, roller is missing. 

Where is intake adjust screw?

See the diagram of intake screw to loosen to adjust will be #28 as it is in cam #14

boat intake adjust

Which the Idle adjust screw on Evinrude?

The idle adjust screw is the one that attaches the arm to both carbs.
Before spinning the screw note down its actual position.So if idle gets wrong,you know its actual position,to bring it to normal idle state.

How to prime the system?

There is the little red arrow valve on the left side above the control arms toward the back of the engine.
That little red valve is the manual setting for the primer system. Turning it the other way has the same effect as pushing in on the key for the choke position. The small handle should be lined up with the solenoid. You will feel a small click when it goes back to the position it should be.

Some cases turning that valve will make the engine receive power.And all sorts out.
But if in case this works temporarily then you definitely have carbs issue.Re-synchronize the carbs.If you are not able to set it,then get it done at proper professionals.

Suppose if turning that red valve  momentarily fixed your problem, then after a little bit the engine floods out and fuel starts flowing out from front, then that tells you that the high speed jet is plugged or needle and seat are plugged up in one or both of the carbs. They should both be removed, cleaned and carb kits installed.

This details will help.

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