1975 Johnson 25HP won't start

CatfishMN

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Re: 1975 Johnson 25HP won't start

Hi,

I am going to do the lower unit oil as well. Just wondering if this motor takes the 'Hi-Vis' lubricant. I don't have my manual with me and wanted to stop on the way home from work.

Thanks!
 

Camo Joe

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Re: 1975 Johnson 25HP won't start

Sorry CatfishMN.............I didn't get back to you .......I've been busy with lots of work.............just listen to the Commander..........Check fuel pump.....carb........etc............It will purr like a kitten when you get these things fixed.............good luck!
 

CatfishMN

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Re: 1975 Johnson 25HP won't start

Well, I did the carb kit, soaked and cleaned the carb, blew out the tougher areas with air, put in new seals, etc. and reassembled and reattached. It still won't start.

Here is my starting procedure:

1. Make sure motor is in neutral
2. Pump ball until tense
3. Move throttle to 'start'
4. Pull out choke
5. Pull cord

I get nothing at all. Any ideas as to what to do next?

- fuel pump works
- spark plugs get spark
- motor started right up when I bought it a few weeks ago

I am at a complete loss here.
 

bktheking

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Re: 1975 Johnson 25HP won't start

Did you set the idle needle properly when reassembling?
 

CatfishMN

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Re: 1975 Johnson 25HP won't start

How do I tell that? It wasn't part of the instructions that came with the carb kit. Did I miss something?

Also, it won't even turn over. All I get is the rope pulling.
 

bktheking

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Re: 1975 Johnson 25HP won't start

The motor won't turn over, did you have the recoil off? Turn the idle needle in all the way (just till it seats) and back it out a turn and half and try it. You must have had the idle needle out to clean the carb, no?
 

CatfishMN

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Re: 1975 Johnson 25HP won't start

Hi BK, OK, yeah I had the needle out and I turned it in until tight, and then back out a full turn before reconnecting it to the 'slow speed' knob.

I am getting recoil with the starting rope, it just doesn't sound like it is trying to turn over is what I meant.

I don't know where to go from here with it.
 

bktheking

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Re: 1975 Johnson 25HP won't start

Pull the carb box off, open the choke, spray 50:1 into the carb and close the choke and try and start it.
 

CatfishMN

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Re: 1975 Johnson 25HP won't start

Pull the carb box off, open the choke, spray 50:1 into the carb and close the choke and try and start it.

Do you mean the front plate, including the needle?

Thanks again.
 

bktheking

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Re: 1975 Johnson 25HP won't start

No leave the needle in, yes just the plate/box whatever is in front. Sounds like the carb might be an issue still. Did you have the welch plugs out of the carb when you cleaned it? They can be a real bugger to get perfect, I've cleaned carbs 3+ times in order to get them right, heck I cleaned my KH7 carb installed a full kit and it ran like ***** until last night when I found a micro sized pebble in the air orifice tube.
 

CatfishMN

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Re: 1975 Johnson 25HP won't start

I'll give it a shot in the morning. Also, gas was running out of the carb again. Does this mean it was flooded?
 

bktheking

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Re: 1975 Johnson 25HP won't start

It means you didn't install the kit properly. Carbs are like a toilet, water rises in the tank on a toilet and the float rises causing the water valve to shut the water off. Same thing , gas goes into the float bowl, float rises causing the needle to contact the seat. Was it running out the carb throat? Typically either the float is the wrong way around, you forgot the clip that goes from the float to the needle or the float height is wrong.


Now this is a true fact if gas was running out of the carb while pumping the bulb.

If it only did it while trying to start then that was the choke pulling fuel.

Can you answer the above statements?
 

CatfishMN

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Re: 1975 Johnson 25HP won't start

I'll check both again in the morning. The kit said to put the carb at 3/4" when upside down and hanging and I thought I got pretty close to that.

Could the angle of the motor itself have any effect on this? Like how it is mounted? Right now I have it tilted a bit forward on the stand to accommodate the water tank.
 

bktheking

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Re: 1975 Johnson 25HP won't start

Could be a finicky motor, try starting it level. There may be something else going on here. Has the compression been verified?
 

CatfishMN

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Re: 1975 Johnson 25HP won't start - UPDATED

Re: 1975 Johnson 25HP won't start - UPDATED

Hi everyone. Just thought I'd post an update to this thread. After much hair pulling and frustration, I figured out the problem.

Turns out there was a piece missing on the choke linkage so when the choke was pulled out, the front and back plates were not moving in tandem. I rigged it up with a piece of wire to give it a try, and she started on the 2nd pull and ran pretty well after that. I guess sometimes you just gotta step back and take a second look at it.

I really gotta thank BK for all his help and patience on this one. Thanks man!
 
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