1980 Johnson 25hp... weird issue

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blankenship_kevin

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I was having a few issues with my 1980 Johnson 25hp. It was very cold natured and was having issues idling among other things. I decided to pull the carb off and clean it and put a new carb kit in it. It is factory electric start so in order to remove the carburetor I had to remove the starter. Now, after getting it all back together it will not even try to fire. I know it is getting fuel because I can smell it in the cylinders when I remove the plugs. I also know that it is getting spark cuz I tested that by ground them to the block. Is there anything that anyone can think of to try? I wanted to rule out a fuel issue so I sprayed a little bit of starting fluid in the cylinders and it still did not fire off. I am baffled!
 
oldcatamount

oldcatamount

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Re: 1980 Johnson 25hp... weird issue

Try to start it, then pull out the spark plugs and look at the electrodes. You should see wet fuel/oil on the plugs themselves. Just sniffing may be a bit misleading. Also be sure your kill switch is on.
 
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blankenship_kevin

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Re: 1980 Johnson 25hp... weird issue

oldcatamount said:
Try to start it, then pull out the spark plugs and look at the electrodes. You should see wet fuel/oil on the plugs themselves. Just sniffing may be a bit misleading. Also be sure your kill switch is on.
Click to expand...

Yes, there was fuel on the electrodes themselves. I will look into the kill switch. As of now, the kill switch itself is broken and doesnt have the ability to kill the motor but it may be grounded further up in the wiring.
 
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AlTn

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Re: 1980 Johnson 25hp... weird issue

if grounded, it grounds the power pack and no fire...plug wires possibly get reversed?
 
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AlTn

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Re: 1980 Johnson 25hp... weird issue

yep...but at the wrong time...firing order is 1-2..or..top-bottom
 
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blankenship_kevin

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Re: 1980 Johnson 25hp... weird issue

Ok, thank you! I am going to investigate into it a little further. I also had a suggestion from a mechanic at a local boat shop that something is goofed up in the carb causing it to flood. I can assume that even after spraying starting fluid into the cylinders if it is flooding itself that the fluid won't ignite either.
 
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Xcusme

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Re: 1980 Johnson 25hp... weird issue

Note:
Avoid Starting Spray.....it had ZERO lubrication. For starting purposes, just spray gas/oil mix (your normal fuel) into the carb throat..
Good Luck....
 
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AlTn

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Re: 1980 Johnson 25hp... weird issue

get yourself an open air gap spark tester ,< about any auto parts place has them >, and set it to 7/16" the spark must be able to jump this gap for you to rule out ignition problems on cold start..other issues concerning spark may arise when the engine is hot, but that's another post...if spark is good you should be able to start the engine with a little fuel mix in each plug hole. The real deal is compression,spark,fuel...might amounts at the right time. Have you ever tested or had tested for compression?..recall the numbers?
 
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blankenship_kevin

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Re: 1980 Johnson 25hp... weird issue

AlTn said:
get yourself an open air gap spark tester ,< about any auto parts place has them >, and set it to 7/16" the spark must be able to jump this gap for you to rule out ignition problems on cold start..other issues concerning spark may arise when the engine is hot, but that's another post...if spark is good you should be able to start the engine with a little fuel mix in each plug hole. The real deal is compression,spark,fuel...might amounts at the right time. Have you ever tested or had tested for compression?..recall the numbers?
Click to expand...

I haven't ever tested it but I am going to this week when I can work on it again. I am also going to check the spark. Thanks for your help!
 
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