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OMG! Why wont this 71 25hp fire up???? Help

Indicafilms

New member
I am so frustrated that I joined this website to ask for help. I’ve been turning wrenches for over 40 years so it’s not like I don’t know what I’m doing but this motor has me baffled.

I got this 1971 Johnson 25 horse tiller pole start that looks to be just freshwater use. First thing I did is check compression with two gauges and I’ve got 120 pounds on each hole. I moved onto spark and I didn’t have any. I started replacing things individually getting spark losing spark getting spark blah blah blah eventually to the point now that the entire magneto I’m talking coils points condensers and wires back to the spark plugs are brand spanking new.

I’ve been spinning the fly wheel with a drill and now I have nice strong spark on both plugs.

I then moved into the carburetor which was pretty darn clean to begin with. I cleaned everything with guitar strings and although I’m not 100% sure it’s a great carburetor I’m just trying to get this damn thing to fire up one time.

so here is the thing that baffles me. I have very good compression a very good spark and I’ve tried everything with the carburetor but I don’t even get the slightest ignition I’m just talking about a one second explosion in the cylinders nothing. I’ve tried pouring pre-mix down the carburetor throat as well as starter fluid (yea i know please spare me). I have even been pouring things into the cylinders themselves putting the spark plugs back and spinning it. No matter what I do not even get a single fire explosion nothing.

so I’m 100% certain that I have plenty of compression. I am 100% certain that it’s not a carburetor issue because I’ve tried everything and the plugs even come out wet sometimes so gas is coming into the cylinders. I had a lot of trouble with the spark but these babies are sparking up I can’t imagine spark being an issue.

anyone have any ideas? It’s almost as if to me the timing is way way off like 180° and it’s firing on the down stroke which would make it never fire but I’ve gone through everything and no matter what there’s no way anything could be wrong I’ve even swap the wires out from spark plug the spark plug. I’ve been turning wrenches for a long time and I know that if I pour some gas into those cylinders there should at least be a spark for a second or two and that would make me very happy but this thing just seems dead.

I really hope there’s some old timer Evinrude Johnson guy out there about to give me some magical advise thank you
 
Yes but i have tried it every way imaginable. Even if i come back the next day and spray a lil starter fluid and hit it with the drill i get zero combustion. It just spins
 
I probably made it Sound like I’ve been dumping tons of fuel in but that’s not true I’ve been fixing engine for a long time I know a little squirt is all it takes but this little guy just doesn’t want to ignite
 
No need for a drill to start one of there motors.-----When you put 10 drops of fuel in each cylinder it should " bark like a wild dog" I say.-----If not , then pull flywheel and post some pictures if what is under there.----This should be easy to figure out.
 
No need for a drill to start one of there motors.-----When you put 10 drops of fuel in each cylinder it should " bark like a wild dog" I say.-----If not , then pull flywheel and post some pictures if what is under there.----This should be easy to figure out.

I will. But like i said its all new. In fact im thinking about putting the original coils back because I have suspicions about these new ones.
 
Somethings been bothering about these coils the originals ohmed out at about 6.3 kohms while the new ones are about 14 kohms. Thats a big difference im gonna swap the old ones back and report
 
Well I took off the magneto and I put the original coils back in. It seems like the spark is a hair better and I am able to get both plugs to jump a 5/16 gap. I put it all together squeezed gas into the carburetor and hit it with the drill and at least it started to try to start. When I gave it full throttle and hit it with the Drill Eureka it started right up ran for two seconds and sounded great. I then put the pull start mechanism back on it and I was able to start it at full throttle only for a second or two.

so I’m pretty happy and I’m at a new stage of troubleshooting which will be messing with the carburetor and making sure that fuel is going in the right way does anybody have any advice about the carburetor as far as how these engines like to be started do I have to put the choke? Why would it only start at full throttle? It seems like if I turn the tiller handle the cam that opens the throttle up hardly does anything until the very end. Also how many turns should I start with that big needle valve in front? Any help with the carburetor at this point will be appreciated thanks
 
Did you double check to make sure you have not crossed the two coils? I only ask as I did just that yesterday in trying to revive an old 15hp. I was getting nice beautiful spark and carb was completely clean. I pulled and pulled and pulled. I sprayed starter fluid right into the cylinders…nothing. Then I noticed that the striped blue and orange lead for coil was on coil #2…ooops.
 
Did you double check to make sure you have not crossed the two coils? I only ask as I did just that yesterday in trying to revive an old 15hp. I was getting nice beautiful spark and carb was completely clean. I pulled and pulled and pulled. I sprayed starter fluid right into the cylinders…nothing. Then I noticed that the striped blue and orange lead for coil was on coil #2…ooops.

yes i doubled checked
 
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