1977 25hp Johnson Should I Try

[KC-1]

hey guys here's my problem im wondering if i should put the time in to try and fix or if it's a big problem! when i turn the key the starter turns and the flywheel also and it just keeps going doesnt actually try to crank and after about 20 seconds of trying it blows a puff of air (big violent puff) out the exhaust and water pee hole maybe like its loading up and then releasing it and if i go another 20 seconds it does it again. it turned over one time and that was it couldnt get it to do it again. it's getting gas and spark i checked. any help would be great. thanks guys

 

[jasper60103]

Re: 1977 25hp Johnson Should I Try

How's your compression? Did you check spark with a spark tester?
Lets see what the numbers are.
In the future, I wouldn't crank it that long. It's got a problem.

 

[KC-1]

Re: 1977 25hp Johnson Should I Try

thanks i'll get a compression check as soon as i can. i didnt use a spark plug tester but it looked like it has pretty good spark. any guess why it might be puffing out air like that? i dont want to take it to a shop and sink a couple hundred dollars into it. it's not worth that. thats why i asked you guy's if you had any clue what itis or what i could try to determine the problem. thanks again

 

[KC-1]

Re: 1977 25hp Johnson Should I Try

oh the guy said it was winterized and would take a minute to start! that is why i tried so long he also said it would smoke pretty bad for a minute when i started it the first time. he said to replace the spark plugs after it quit smoking?

 

[jasper60103]

Re: 1977 25hp Johnson Should I Try

just an FYI.
You can borrow a compression tester for free at Autozone or Oreillys auto part stores. Simple enough test to do yourself. We can help.

 

[bktheking]

Re: 1977 25hp Johnson Should I Try

Try swapping the plug wires around.

 

[tashasdaddy]

Re: 1977 25hp Johnson Should I Try

agree ^^^^ and if that does not do it. are you sure fuel is getting to the plugs. what do the plugs look like. if it is not firing, they should be wet with fuel..

also could be the flywheel has sheered the woodruff key, which will throw the timing off, usually causes backfire.

 

[FAC]

Re: 1977 25hp Johnson Should I Try

like the others have said you need compression, fuel and spark (at the right time) for it to run i had very similar symptoms and it was a sheared flywheel key

 

[KC-1]

Re: 1977 25hp Johnson Should I Try

thanks guy for the responses. update i got it running and it run and cranks great i didn't have to do much just a little caressing! the only problem now is it will only idle at half throttle and up any lower and it dies out but runs fine in gear (like it should at low idle). i took the carb off and cleaned it but it didnt need it, it looked imaculate and messed with the idle screw but it was set right. im not sure what i should check to possibly find the problem. thanks for the info on the compression tester im gonna do that. what about a spark tester would i have to take it to a shop?

 

[ezeke]

Re: 1977 25hp Johnson Should I Try

You have to keep it fully choked for a cold start.

 

[jasper60103]

Re: 1977 25hp Johnson Should I Try

... thanks for the info on the compression tester im gonna do that. what about a spark tester would i have to take it to a shop?

yea, an auto parts store would have a spark tester. Only cost about $6-7.

 

[KC-1]

Re: 1977 25hp Johnson Should I Try

So does anyone know what my idle problem could be?
Thanks again guys

 

[jasper60103]

Re: 1977 25hp Johnson Should I Try

So does anyone know what my idle problem could be?
Thanks again guys

Ok, you said it would not run faster than idle in neutral, correct?
This is normal operation. Your motor should not throttle up in neutral.

Also, there is a idle speed adjustment (port side of motor) to stop the throttle from going too low before the engine quits. You just have to adjust the screw.

 

[restornator]

Re: 1977 25hp Johnson Should I Try

Also check the exhaust relief valves, a motor sitting real long, it's a cozy place for bugs to hide out