Evinrude E-NATION, for those dedicated to water, power, fishing and fun
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Skipper
Posts: 5
Registered: ‎10-22-2019

two certified mechanics cant fix my 1980 75 hp Help !

Motor started bogging at half throttle, continued to get worse over time. Finally, wouldnt take gas at all in gear . Idle great rev. in neutral but lays an egg when put in gear. Sounds like running on 1 cylinder..No power....  Rebuilt carbs  (2 sets)  no help.  new gas lines, tank, new reed valves, new coils, great compression. mechanic says all electrical parts check out. ( Stator,timing assy. power pack.)  What could it be?   Short or grounding somewhere?  Mechanics have given up !  Help Please !   Mr Bill  43

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Admiral
Posts: 8,624
Registered: ‎07-14-2011

Re: two certified mechanics cant fix my 1980 75 hp Help !

Do a cylinder balance test to see which cylinder(s) are not putting out equal power at some rpm above idle.

 

You can use a clip-on timing light to check the spark on each one, a pressure gauge for the fuel delivery, and a pump can with 50:1 mix to squirt into each carb to see if there is a lack of fuel flow. Refer to a factory service manual for specifications and procedures.

 

 

 


"There is never just one thing wrong with a boat";
                    -- Travis McGee, main character in a book series by John D. McDonald 


 



***************

The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.

The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.


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Skipper
Posts: 5
Registered: ‎10-22-2019

Re: two certified mechanics cant fix my 1980 75 hp Help !

Will pass this on to mechanic. Thanks
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Captain
Posts: 716
Registered: ‎08-20-2017

Re: two certified mechanics cant fix my 1980 75 hp Help !

Mechanical basics. Compression, Spark, Fuel/air.
Compression is there or not and won't change.
Spark can break down/stop under load but can be verified by a timing light.
Fuel is harder to test but Bills advice of squirting some fuel in the carbs under load is an easy diagnostic steps.
Carburetors have an idle jet and a main jet. However there are two or three transition ports of increasing size which add fuel between the idle jet stage and the main jet stage. On all metal carburetors these are located under a pressed in metal Welch plug and are often overlooked when cleaning.
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Skipper
Posts: 5
Registered: ‎10-22-2019

Re: two certified mechanics cant fix my 1980 75 hp Help !

I am being told that the top carb spits out gas which tells me  bad reed valves. So they replaced the reed valves with good ones and it still spits gas and lays an egg when given throttle even in neutral.  Can it be something internal ? we got good fire, good gas and air.  So far we are stumped, mechanic says it should be running like a new one.....Any more input is appreciated ! 

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Admiral
Posts: 8,624
Registered: ‎07-14-2011

Re: two certified mechanics cant fix my 1980 75 hp Help !

 

 

Are these "certified mechanics" employed at an authorized Evinrude dealership, an independent repair shop, or at a different brand of outboard motor dealer?

Do they reference the official factory service manual?

 

 

 


"There is never just one thing wrong with a boat";
                    -- Travis McGee, main character in a book series by John D. McDonald 


 



***************

The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.

The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.


Highlighted
Skipper
Posts: 5
Registered: ‎10-22-2019

Re: two certified mechanics cant fix my 1980 75 hp Help !

Its a yamaha dealer marina, guy is a retired airforce engine guy with 30 years of outboards. He is VERY by the Evenrude manuals very old school and dont doubt him or you will catch hell. The other is a certified evenrude dealer that looks like Ernest T. Bass  but  these guys are friends so today they were suppose to get together and check things together. They are very frustrated and needing to stand back for a while , settle and work thru the process  again. This info comes from the service manager at the yamaha   marina.  They are trying to help me.     Any advice from an Admiral is appreciated. 

Highlighted
Admiral
Posts: 8,624
Registered: ‎07-14-2011

Re: two certified mechanics cant fix my 1980 75 hp Help !

An engine needs to draw in a correct fuel:air mixture that is adequately compressed and ignited at the proper time and the exhaust expelled for a motor to run satisfactorily.

 

If any of the requirements are missing or out of spec, the motor will give problems.

 

A good technician checks each of the systems for proper operation.

 

 

 

 

 

 


"There is never just one thing wrong with a boat";
                    -- Travis McGee, main character in a book series by John D. McDonald 


 



***************

The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.

The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.