johnson sea horse 75

[F_R]

Re: johnson sea horse 75

So I carefully read the instructions on how to time magneto and sync throttle to magneto. The throttle linkage was a little off but the belt timing was correct.
When I was starting it earlier I was opening the throttle by actually opening the throttle arm that comes directly out of the carb, so that linkage made no difference although it saved me a step later down the road once I get it running.

So now im completely out of Ideas. As far as I know I have decent compression, good spark, properly timed magneto, carbs are clean.

Any ideas?

Derek

Well, if everything is as you say it is, I'm about out of ideas too. But just a comment, I hope you aren't still opening the throttle at the carburetor. That will stop even a good running motor. The spark has to be advanced at the same time or it will immediatly conk out. That's why the sync adjustments are so important.

Still unanswered is the flywheel key question---or I missed the answer. Are we positive that the spark plug wires are on the right plugs and/or in the right towers on the cap? Do we know that something hasn't fallen down through the carburetor and is blocking a reed open?

 

[steamking123]

Re: johnson sea horse 75

I guess that makes sense about using the throttle arm. I won't do that anymore.

I double checked that the spark plug wires and the corresponding spark plugs. I looked at the numbers that are on the magneto casing and then followed them to each cylinder. Correct me if Im wrong. If I am looking at the motor from behind the boat it goes like this.
top right cylinder is #1
top left is #2
bottom right #3
bottom left is #4

As far as the reed goes, I don't really know. I have never taken apart anything below the carb. Is that something I need to do? What is a reed and how would I know if it was functioning?

Also in regards to the flywheel key. Are you referring to the flywheel above the magneto? When I looked at the condenser points the metal piece you slide the flywheel onto (to hold the flywheel consistent on the shaft) it was in good repair. The flywheel and the shaft spin together.

 

[F_R]

Re: johnson sea horse 75

I guess that makes sense about using the throttle arm. I won't do that anymore.

I double checked that the spark plug wires and the corresponding spark plugs. I looked at the numbers that are on the magneto casing and then followed them to each cylinder. Correct me if Im wrong. If I am looking at the motor from behind the boat it goes like this.
top right cylinder is #1
top left is #2
bottom right #3
bottom left is #4

As far as the reed goes, I don't really know. I have never taken apart anything below the carb. Is that something I need to do? What is a reed and how would I know if it was functioning?

Also in regards to the flywheel key. Are you referring to the flywheel above the magneto? When I looked at the condenser points the metal piece you slide the flywheel onto (to hold the flywheel consistent on the shaft) it was in good repair. The flywheel and the shaft spin together.

The carburetor is mounted on the intake manifold. Between the intake manifold and powerhead is a plate about 1/4" thick---the reed plate. Mounted on the reed plate are a whole bunch of reeds---OMC calls them leaf valves. They are thin pieces of spring steel that act as flapper valves allowing fuel & air to pass only in one direction. Failure of one is extrmely rare.

The "Flywheel" is that honkin' big rotating piece under the recoil starter. It is keyed to the crankshaft. If the key is sheared, the flywheel (and belt and magneto) are out of time in relation to the crankshaft. The key never fails if the parts are good and they are assembled correctly. However, if somebody had it apart and DIDN"T assemble it correctly, key shearing is almost guaranteed. Also almost guaranteed is catastrophic damage to the flywheel and crankshaft. Your manual should show the correct procedure--read and heed.

 

[steamking123]

Re: johnson sea horse 75

Its running. finally it starts and runs. it definitely runs rough but it stays running most of the time.
I am not exactly sure what made it run. When I did the link between carb and mag, I tried to start it but it didn't run. I increased my idle today and it pretty much fired right up. I guess it must of been a combo between linkage and idle settings.
I didn't let it run very long because I was afraid of overheating. Someone mentioned that I have to replace my impeller before I let it run much. is there a way to test to see if impeller is working correctly.

 

[cougar1985]

Re: johnson sea horse 75

Its running. finally it starts and runs. it definitely runs rough but it stays running most of the time.
I am not exactly sure what made it run. When I did the link between carb and mag, I tried to start it but it didn't run. I increased my idle today and it pretty much fired right up. I guess it must of been a combo between linkage and idle settings.
I didn't let it run very long because I was afraid of overheating. Someone mentioned that I have to replace my impeller before I let it run much. is there a way to test to see if impeller is working correctly.

i have the 63 evinrude version of yours ,75 starflite.i used a cheap large tote box and filled her full of water and lowered the motor into it,started and after a few seconds you should be able to put your hand by the hole in the mid-leg of your motor and you will feel water spitting out.its the same hole the exhaust comes out of.also feel the cylinders with your hand ,if their hot to the touch your impeller is not working.the safest way is, if your not sure, to replace the impeller and then you will be sure!

 

[steamking123]

Re: johnson sea horse 75

I started it up while the motor was submerged past the screen intake. water (mist spray) comes out of the exhaust. Does this mean impeller is ok?

Although it runs it wont stay running for very long. it stays running the longest at idle speeds (several minutes) but when I rev it up it will die after a few seconds.

I set the slow speed setting at 1 and 1.5 and then 2 to try to see if it would work better, I also did the same with the high speeds setting, but everything I did just seemed to make it worse. It still seems like something is not working right. after running a few minutes I pulled out the plugs to see if all cylinder were running, and each spark plug was a nice golden brown. Also each of the cylinders were warm.

It seems like the motor is either not getting enough fuel or getting too much. But truthfully I don't really know.
While running I tried pumping the prime from the gas line to see if maybe that would help it keep running. It didn't help. Does this mean I am running too rich?

F.R. because its starts now and runs does this mean that the flywheel key is still good? also What about the reeds. is this still an avenue I need to go down?

 

[steamking123]

Re: johnson sea horse 75

After I had done all the things that We talked about on here, the motor would start and run for a few seconds to a few minutes, and sometimes it wouldnt start at all. I couldn't figure it out.

Today, I checked my spark again, and I had a strong brilliant spark. I decided that I was going to exchange the brand new coil from my parts motor to the motor I have been working on. I didn't think it would fix anything but I thought I should change it anyways so I wouldn't have to change it later down the road.

I pulled apart the magneto and to my surprise the coil shell had cracks running in every direction. it was like somebody to a hammer to it then put it back on the motor. I replaced the coil.

To my surprise, for the first time the boat purred like a kitten and roared like a lion when given throttle. I was in disbelief that a coil that was in such terrible condition was still giving out spark (intermittently)

After performing every maintenance check and procedure I could come up with, it turned out to be the coil. how simple. At least I know now that everything else is in tip top shape.

Thanks to everyone for all your help and for sticking with me until I got it. A special thanks to FR for all this time and help. and thanks to oldrudedude for being old and rude and thats it.

 

[Willyclay]

Re: johnson sea horse 75

Great news! It's usually the simple stuff.