96 Johnson 15 twin cylinder

[ddennis]

Could someone tell me if the screw with a spring behind it is the low speed mix adjuster on this model? I only see one externally accessable screw on the carb.

Also how much smoke should I be getting when running on the cups just off idle?

I think it is too lean as I am having a hard time getting a stable idle on this one and it smokes a bit more than I think it should. It will idle for a 10 - 15 secs then starts bogging down and losing rpm.. I can rev it a bit and let it settle down for another 10 - 15 secs and then does the same. Does the carb need to be rebuilt on this?

 

[OBJ]

Re: 96 Johnson 15 twin cylinder

Yes, that's the low speed screw Dennis....but.....trying to tune the engine on muffs just don't work. You need to get the engine in the water to do the job right. You can expect a little more smoke on muffs because the engine just isn't working as hard and not burning all the fuel/oil mix.

Is this engine new to you and if so, do you know any maint history on the engine? Block temp good....not running cold?

 

[ddennis]

Re: 96 Johnson 15 twin cylinder

Thanks OBJ.. I have a factory manual on order..should be here any day now. This is a new to me engine. The block temp seems to be good..warm to the touch. Doesnt seem to be running cold. I should have it in the water to test it out better today...have to finish wiring up the trailer lights. I suspected that the engine needed to be in water to run correctly..you just confirmed it!
Thanks!

Luckily I am a fairly well mechanically inclined person so working on this thing should be easy for me once I get the manual in!


This is the first boat and motor I have ever had.. I have a 12-13 foot vhull johnboat this is going on and the kids are pressuring me hard to get off the bank to fish! Hence me trying to get it going for saturday morning for them! My boys birthday is in 2 weeks and he told me he wants to night fish with me for his birth day. This was an empty hull when I got it 2 weeks ago so I have been bustin my butt getting it wired, cabled, rigged and everything else it needed to have done to it to make it safe and functional! I work 10-12 hrs a day as a network manager/engineer for a fortune 500 company during the day and 4-5 hours a night working on this trying to satisfy his birthday request!

 

[ddennis]

Re: 96 Johnson 15 twin cylinder

Also...not sure on the maint history. However when I got it the first thing I did was drain the carbs, change the oil in the bottom end and replace the sparkplugs. Bought a brand new tank and fuel line, filled it up with mid grade, added stabil to it and used Johson mix.