85 Johnson 25 Hp Carb No Top End

[ABES]

Idles a starts fine but when i give it gas about 1/4 throttle won't take it boggs down and sometimes dies out when in gear, but out of gear it takes gas at 1/4 throttle,its just when i put a load on it in gear also notice from exhaust dark oil and gas/sludge,is that normal? not burning fuel right i think high end jet cloged,mix is 50 to 1 motor has 100 to 1 but was told to go with 50 to 1 NEED HELP !! ANY SUGGESTIONS I want to get somemore fishing in this fall thanks..

 

[Daviet]

Re: 85 Johnson 25 Hp Carb No Top End

Start by checking compression, spark and fuel delivery. It sounds like it may be running on one cylinder. What is the condition of spark plugs? Has motor been sitting for awhile? Running 100/1 is double the oil ratio, start using 50/1, could have caused carb problem.

 

[kbait]

Re: 85 Johnson 25 Hp Carb No Top End

100/1 is actually half of the oil as 50/1. Run 50/1. Some of those motor years indicated 100/1, but backed out later. I worked on one that had those symptoms, and after confirming spark, and using new plugs, had the same problem.. I reset the float so it was exactly even with the carb body when inverted (see a billion posts about johnson/evinrude carb rebuild/cleaning), and it worked fine. Also, before you hook the fuel line from the pump back up to the carb, hook up your fuel tank and give the bulb a squeeze or two to confirm that the fuel will come out of the line to the carb easily. If not, make sure the fuel pump screen (just beneath the black plastic 'cap' that you remove with a coin on the screw in the center) is clean. DON'T pull the whole fuel pump apart unless you're ready to swear and throw beer! Lot's of little parts in there! Good luck!

 

[ABES]

Re: 85 Johnson 25 Hp Carb No Top End

Thanks Guys, But Is That Normal For Unburned Gas/ Oil Sludge Comming Out Of Exhaust? It Was Smoking At Frist Then After It Ran For 5 Min Or So It Stoped,i Just Bought The Motor The Guy Didnot Use It Much And You Can Tell Real Clean But Ran It Once In A Wile Just To Run It,and It Did Run Good Out Of The Water...if There Is No Water Around For A Water Test You Take A Chance And End Up Putting More Money In It, Then You Have More IN IT Than The Motor Worth,, I Hope Thats All It Is A Carb Rebuilt..

 

[crxess]

Re: 85 Johnson 25 Hp Carb No Top End

Your description indicates one cylinder is not firing under load or Possibly fuel starvation.

Rebuild Carb
Compression test - numbers close on both cylinders
test On water.

If still cutting out-
Under load pull 1 plug wire and not change in motor
re-connect and pull other plug wire.
If one cylinder makes no change - Bad plug/plug wire/coil/etc. on that side.