Need Help Frustrated

[JohnnyG1]

Ok this is my first post and from what I have read on this forum you guys rock.
I have a 1990 15hp Johnson been in storage for 7yrs. I have change the impeller and just finished the carb rebuild got it all together and set the idle screw set 1 3/4 out to get it to run. Here is the problem I pull the choke out and when it goes in it dies I turned the idle screw 1/2 turn and it wont start if I hold the choke at half it idles great. But I cant throttle up I have tried to adjust the idle screw with no change I am stumped. I need HELP!!!!!!!!

Thanks in advance

 

[Joe Reeves]

Re: Need Help Frustrated

Either you've overlooked something within the carburetor (fouled), or the carburetor isn't adjusted properly.

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

 

[tashasdaddy]

Re: Need Help Frustrated

http://forums.iboats.com/showthread.php?t=244013

 

[JohnnyG1]

Re: Need Help Frustrated

Ok guys I'll give that a try. First I will take it a part again and see if I did something wrong. Is their a drawing of the carb. so that I can make sure I put it back the right way so I can rule out the wrong assembly.

 

[NelsonQ]

Re: Need Help Frustrated

Ok guys I'll give that a try. First I will take it a part again and see if I did something wrong. Is their a drawing of the carb. so that I can make sure I put it back the right way so I can rule out the wrong assembly.

Without the model #, hard to determine but if you go to www.johnson.com/en-us/ Select part and accessories

Here is the pic of a 15HP Johnson carb from one of the 1990.

 

[JohnnyG1]

Re: Need Help Frustrated

sorry model # J15resr

 

[JohnnyG1]

Re: Need Help Frustrated

thanks for the drawing but I did see some thing odd the gasket that it shows (part #17) is not the sameone I originaly replaced. And yes before I put the motor in storage it ran great.

 

[NelsonQ]

Re: Need Help Frustrated

sorry model # J15resr

Go to the link I mentioned, you'll get a breakdown of all the parts (by year/HP/model) that will hopefully help. For the proper assembly/disassemble, get the original service manual. It'll help.

 

[JohnnyG1]

Re: Need Help Frustrated

ok Thanks for all your help I will let you know what happened

 

[JohnnyG1]

Re: Need Help Frustrated

ok got the carb. out and rebuilt again and still the same thing now what is the next thing? Do I just keep doing small ajustments to the idle screw or the slow speed knob?

 

[JohnnyG1]

Re: Need Help Frustrated

bumped

 

[david_r]

Re: Need Help Frustrated

if you have cleaned and adjusted the carb as stated above and still have a prob you may have water in your gas or an air leak.....get some carb cleaner and get her to start and run by any means possible and spray carb cleaner around the gasket areas-youll know if shes suckin air

 

[Tim Frank]

Re: Need Help Frustrated

I'd bet on blockage in the low speed jet passages.
When you rebuilt the carb did you remove the welch plugs to facilitate cleaning? If not, there may be some gunk that you were not able to get out.
Also, do you have a compressed air source? That is really a help....I've done lots of carbs w/o compressed air, and cut the corner of not r&r the plugs....but have had a few of those where i had to redo the job.
If it's the carb that I'm thinking of, the low speed jet is up top and there is a welch plug at the end of the jet bore. I'd look at the passages behind that plug.