1978 70Hp Johnson - Choke Problem??

[deofc]

I like this site and have found many helpful ideas here. I have a 1978 70 HP Johnson OB, Bought it used 2 years agoa. Have had what I consider the usual problems with a used motor - bad power pack.I run it about once a week. about 6 weeks ago the choke on the key (the kind that you push on the key as you turn it to start) quit workning. No real big deal, I just take the cover off and manually choke it and it starts right up and has run fine. Now, it still starts fine and runs at idle great but as I increase the throttle it starts running sluggishly and sort of bogs down. If I remove the cover and manually push the throttle linkage it runs sluggishly and then within a few seconds of this it starts running great and I can put the cover back on and use the throttle normally. I can live with it like this but would rather get working right. Any ideas. Thanks.

 

[R.Johnson]

Re: 1978 70Hp Johnson - Choke Problem??

Does this problem dissapear after a few minutes of running time? If so, the engine is not up to running tempature. Since you no longer can tickle the choke at the key switch it would be more noticble. Ckeck the voltage at the purple wire going to the choke solinode. If you have voltage, and before you replace the solinode, check the choke adjustment. With the engine off, the solinode plunger should protrude 5/16 of an inch. To adjust loosen choke bracket, and slide choke housing in, or out. Another thing when you choke it manually, are you pushing the choke knob all the way in? If so, you would defeat the warm-up feature of the choke. Of course if the solinode is burned out, you would not have this feature.

 

[deofc]

Re: 1978 70Hp Johnson - Choke Problem??

R Johnson -- Thanks for the quick reply. The problem goes away after less than a minute of pushing on the throttle linkage. Not sure about the engine getting up to running temperature because I have tried just letting it run at idle for a few minutes and using the throttle lever to increase power. When I do this it just bogs down (keeps running but with the throttle lever pushed to 1/2 -3/4 it just runs a little faster than idle and sputters - kind of like the choke is still engaged but I know the choke is off. Anyway I will check the voltage and the adjsutment. Thanks again for you help.