Running a 25hp 1975 Johnson

[rlowhorn]

I just perchased a 25 hp Johnson outboard. Been having trouble getting it to start when the boat is in the water. The boat is a 14 foot aluminun. The motor run great at home in water, but when I put the boat in the water cannot get it to start. The motor sets deep in the water, is this a problem. This is my first motor and I think the problem may just be me not knowing how to start this motor. Please help, a motor running at home is not much fun. No fish here.

 

[sundede]

Re: Running a 25hp 1975 Johnson

I just perchased a 25 hp Johnson outboard. Been having trouble getting it to start when the boat is in the water. The boat is a 14 foot aluminun. The motor run great at home in water, but when I put the boat in the water cannot get it to start. The motor sets deep in the water, is this a problem. This is my first motor and I think the problem may just be me not knowing how to start this motor. Please help, a motor running at home is not much fun. No fish here.

 

[sundede]

Re: Running a 25hp 1975 Johnson

Your motor is similar to mine. Remember you need air fuel & spark.On mine I found that It would start but die. I left for the lake too soon. I have found the Impeller housing was incorrectly installed & the Coils although gave spark the insulation had failed. It was sparking but I felt that it would not if warm or under load. Use what you know to identify the reason it won't start. You may have flooded it. There seems to be no reason that it would not start just cause of the location. I hope you get it going.plugs? Fuel condition? Fuel/ air ratio? altitude may affect this..others may be able to help more than I can..

 

[tashasdaddy]

Re: Running a 25hp 1975 Johnson

if you are running on muffs at home, the engine has no back pressure on the exhaust. set your carbs a little higher, and it should start ing the water. fine tune carb adjustments on the water, not on muffs.

 

[rlowhorn]

Re: Running a 25hp 1975 Johnson

What do you mean by "on muffs?" At home what I have is the lower housing submereged in a garbage can deep enough that it will pump water. Is that what you mean. I understand that in this condition there is no back pressure, so I can understand why the carb would need to be adjusted to that. I do not know a lot about the carb. on this motor, but assume you are talking about the only adjustment. The fine adjustment at the top.

 

[rlowhorn]

Re: Running a 25hp 1975 Johnson

Sundede, when you say air, fuel , spark; the fuel line from the tank has one hose, but two attaching plugs. I am using a plastic tank from Walmart with a motor attachment that was labelled for Johnson motors. The old tank that my father used had a double hose. I assumed the new attachment gave air in a different way and replaced the double hose. Am I correct?

 

[rlowhorn]

Re: Running a 25hp 1975 Johnson

Also, do you know where I could get parts for this motor. The shifting arm is gone.

 

[Pony]

Re: Running a 25hp 1975 Johnson

The fuel line shouldnt have anything to do with air. The double hose tanks are for older motors that used a vacumm to push fuel through the motor. You motor has a fuel pump so you only need one hose. I am not sure what you mean by "two attaching plugs", but the fuel line should connect to the tank and motor and thats it. Maybe you are wrong on the year.....What is your model number???

What is you starting procedure like? You may be flooding the motor, or not getting any fuel to it.

Pump the primer bulb until full, then choke or prime the motor to get fuel into the carberator, Make sure throttle is in the start position and the motor is in neurtal. Make sure the kill switch isnt detached (or you will get no spark). Pull the rope a few times. If it doesnt start then stop choking the motor and pull again............or if the motor does start stop choking it so that you don't flood it. After the initial starting you really should just have to pull the rope a time or two at most without doing anything else besides having the engine in nuetral and the throttle in start. All this assuming you have rope start.