1974 6hp Johnson Outboard

[danol42]

Can anyone help please. Have a 74 6hp Johnson that will not run unless feeding fuel through the carb. The carb has been taken apart several times, completely cleaned and cannot find any problems with it. All ports are clear and free. Short of replacing it, which I haven't been able to find, not sure what else to do. Any help is appreciated.

 

[Willyclay]

Re: 1974 6hp Johnson Outboard

Welcome to the forum! The members here are great and the experts, which I am not, can help you solve any problem. My qualifications to respond to your post are that I have a 1973 Evinrude 6HP which is virtually identical to yours and have rebuilt several like it for other people. In addition, I have the factory service manual for my specific model so maybe I can help. First, a few questions for you: (1) Is this motor new to you? (2) Have you ever operated this motor previously? (3) When you say "feeding fuel through the carb", does that mean with a spray bottle?
(4) Was the carburetor soaked overnight in carb cleaner and all passages blown out with compressed air? (5) Have you verified that fuel is reaching the carb through the fuel pump? (6) What is the model number of your motor? (7) What are you trying to replace?

 

[luckynickles]

Re: 1974 6hp Johnson Outboard

Look to see when you run it if fuel filter is enptiing out when running or if no fuel filter if pump bowl stays resonably tight if not to both qhestions might be fuel pump

 

[danol42]

Re: 1974 6hp Johnson Outboard

Thanks for the replies.
This motor has been used for many years with no previous troubles. This problem started when taken out from winter storage. It has been stored the same way, same place for several winters. Yes if works fine spraying fuel into the carb. The carb has been soaked for a day and blown out with compressed air. The bowl fills with fuel with the motor running while "feeding it" so the pump works. I would just replace the carb if I could find one. Can't even find another carb to try on it to verify it is the carb although I am not sure what else it could be.

 

[Willyclay]

Re: 1974 6hp Johnson Outboard

Thanks for filling in some of the blanks! You did not mention whether or not using the choke would keep it running without spraying fuel into it. That said, it seems to me almost certainly to be a blockage in the low-speed/idle mixture circuit. When you cleaned the carb, you should have removed the low-speed needle. Did you notice if it has a sharp point on it and the tapered surface is undamaged? Also, when you re-assembled the carb after cleaning, did you use new gaskets from a carb kit? Specifically, did you install new needle valve packing/gaskets? You might want to check the FAQ's in this forum for Joe Reeves' thread on intial carb settings after a rebuild to verify where you are currently. Finally, I had a 1959 Johnson 35HP that started and ran great but would not idle. During the THIRD time through the carb, I found some really hard crud in the low-speed passage that three cleanings had not removed. I had to use a dental pick to get it out. After that, it ran great and idled for the remaining ten years I had it. Hang in there, you can whip it. It's usually something simple. Maybe another member will post in with a better suggestion! The link below should be for your carb which may help your efforts. Good luck!

http://www.marineengine.com/parts/j...6R74C&manufacturer=Johnson&section=Carburetor

EDIT: I just compared p/n's and our carburetors are identical. I can tell you from experience that fuel deposits/dirt/crud likes to hide in the passage under the expansion plug labeled #10 on the parts diagram. It has to be removed, passage cleaned and plug replaced with a new one that is included in a carb kit. Sealed also! Us old guys use clear fingernail polish.

 

[Monte1961]

Re: 1974 6hp Johnson Outboard

The only thing I would do other than what has been suggested, If there is a cork float in it, Get a new plastic one! The coating on can temporally plug carb and make you crazy! Don't ask how I know this! Good luck and post your results!

 

[dazk14]

Re: 1974 6hp Johnson Outboard

The float bowl has a couple passages and the low speed passage gets clogged and often missed - in the float bowl.

The low speed is pulled in a circuit that runs across the bottom and up the port side (as I recall) of the float bowl.

It is easily missed and can be seen along the port side gasket (to carb body) surface.

The gasket has a hole to allow flow up to the carb body - which is usually not clogged...unless the motor was stored on its side.

This fuel source drilling must be clear vertically and horizontally to the base/center of the bowl - which is plugged externally by a lead shot on the bottom.

Normally, the motor will rev up (if you can get it there), but fall flat below ~2k. You may have other issues if this is not your specific symptom.

Good luck!