1976 Johnson 70 running lean?

[Just Fishin']

I know a good bit about engines but never messed with a boat engine, especially 2 stroke. So I will explain the best I can. Motor starts fine. Idles a little high but runs. It seems OK but not the best at a "no wake" speed and really slow cruise. The BIG problem is it falls on its face at 3/4 to WOT. If I leave the hood off, let someone else drive and give it wide open throttle, I can make the motor run like a bat out of hell by closing the choke blades a little but I have to hold it the whole time we are cruising (sucks). I figure it is getting more air than fuel and bogging. When I close the choke blades its fattening up and running good. There is some sort of auto choke position on it that I don't think works at all and frankly don't understand. If it did work would this solve my issue or is there something else I need to do? Thanks guys! Justin

 

[mobiletec]

Re: 1976 Johnson 70 running lean?

I know a good bit about engines but never messed with a boat engine, especially 2 stroke. So I will explain the best I can. Motor starts fine. Idles a little high but runs. It seems OK but not the best at a "no wake" speed and really slow cruise. The BIG problem is it falls on its face at 3/4 to WOT. If I leave the hood off, let someone else drive and give it wide open throttle, I can make the motor run like a bat out of hell by closing the choke blades a little but I have to hold it the whole time we are cruising (sucks). I figure it is getting more air than fuel and bogging. When I close the choke blades its fattening up and running good. There is some sort of auto choke position on it that I don't think works at all and frankly don't understand. If it did work would this solve my issue or is there something else I need to do? Thanks guys! Justin

Your carburators are pluged. The auto choke runs off of a solonoid that energizes only when you push the key in to choke the engine on cold start. You do know there is a choke activator on the key switch on the controls Right?. You can also bypass it on the linkages so the choke will work manually. Rebuild the carbs there plugged for sure.

 

[Just Fishin']

Re: 1976 Johnson 70 running lean?

The auto choke runs off of a solonoid that energizes only when you push the key in to choke the engine on cold start. You do know there is a choke activator on the key switch on the controls Right?.

No I had no idea. I do know that the controls are from an old evinrude. I can try to post a pic of my controls for you.

 

[mobiletec]

Re: 1976 Johnson 70 running lean?

Ok Is there a solonoid near the throtle lever that has a thin wire on it thats you choke solonoid. if you push the key in you should see that solonoid jump the choke flaps closed.

 

[Just Fishin']

Re: 1976 Johnson 70 running lean?

Cool I will try this out and see if it works. Thank you I guess I will rebuild the carbs too. This site is going to be very help I can see already.