Johnson 30hp running very rich after carb rebuild

[mixin]

Thanks for reading this! Trying to do a favor for my father-in-law, I cleaned the carb on his 1993 Johnson 30hp J30TELETA and put in a new OMC carb kit and float. We put the engine in a trash can of water. The engine started very quickly, but immediately began to run very rich. I do not have a tach, but it seemed that I could not get the engine to run at less than 1000-1500 rpm without stalling. While running, the engine was smoking excessively with a strong fuel smell in the exhaust.

The low speed idle screw was set at 2.5 turns out per the service manual. I tried 1/2 a turn in at a time trying to lean it out until I had it turned all the way in. The engine never really leaned out.

Any help would be much appreciated!!!

Thanks,

Mike

 

[fireman57]

Re: Johnson 30hp running very rich after carb rebuild

It takes a little time before the settings kick in. I would wait around 30 seconds between adjustments. If it is running right you can always adjust your linkage to lower your idle. Make sure that you do it on the water or in your trash can with the water at least halfway up your midsection so it has the back pressure.

 

[mixin]

Re: Johnson 30hp running very rich after carb rebuild

Thanks for your reply, I did wait the 30 seconds or so between adjustments - but no dice. The mixture was not even in the ballpark with the low speed needle at the service manual setting - it got a little better as I went through stepping it in, in half turns. Even with it turned only 1/2 turn out it was still running so rich my eyes were burning.

 

[fireman57]

Re: Johnson 30hp running very rich after carb rebuild

Check your slow mix needle and make sure that it doesn't have a ring on the end. If it does then it has been turned in too far and scored. You also should have little felt or some material gasket on it too if I remember right. Don't trust my memory but look it up on a parts diagram. brp dot com should show you.

 

[Monte1961]

Re: Johnson 30hp running very rich after carb rebuild

Thanks for reading this! Trying to do a favor for my father-in-law, I cleaned the carb on his 1993 Johnson 30hp J30TELETA and put in a new OMC carb kit and float. We put the engine in a trash can of water. The engine started very quickly, but immediately began to run very rich. I do not have a tach, but it seemed that I could not get the engine to run at less than 1000-1500 rpm without stalling. While running, the engine was smoking excessively with a strong fuel smell in the exhaust.

The low speed idle screw was set at 2.5 turns out per the service manual. I tried 1/2 a turn in at a time trying to lean it out until I had it turned all the way in. The engine never really leaned out.

Any help would be much appreciated!!!

Thanks,

Mike

When you say you overhauled carb/s, did you remove core/welch plugs? did you allow them to soak for 24 hrs? were they rinsed with fresh water and then blown dry with compressed air including any and and all orifices? Were the carb/s 100% taken apart? If not, I would go back and do it again. Just my 3 cents worth. BTW, Running in tank or can, it will smell more rich that running it on muffs or in the lake!

 

[Cofe]

Re: Johnson 30hp running very rich after carb rebuild

2.5 turns sounds excessive to me. I usually set motors at 1.5 turns out and fine tune from there. Are you using a OMC factory repair manual? I agree with removing the welch plugs and do a proper cleaning.

 

[mixin]

Re: Johnson 30hp running very rich after carb rebuild

Check your slow mix needle and make sure that it doesn't have a ring on the end. If it does then it has been turned in too far and scored. You also should have little felt or some material gasket on it too if I remember right. Don't trust my memory but look it up on a parts diagram. brp dot com should show you.

Right, I did make sure the needle did not have any scoring. The needle only had a spring on it - no gasket that I could see or mentioned in the manual. I will double check the parts diagram, thanks!

 

[AlTn]

Re: Johnson 30hp running very rich after carb rebuild

if you'll go to marineengine.com and find your engine/carb diagram..make certain part no. 7 is in place and the float is parallel with the carb body when the carb is inverted

 

[mixin]

Re: Johnson 30hp running very rich after carb rebuild

if you'll go to marineengine.com and find your engine/carb diagram..make certain part no. 7 is in place and the float is parallel with the carb body when the carb is inverted

I did install part No. 7 (nozzle gasket) - although it's hard to tell how it fits on the carb assembly from the diagram. I installed it by fitting it neatly over the brass tube (nozzle?) that is pressed into the upper carb body which then fits into the well of the lower float bowl. The part did not look like a regular round gasket (as in the diagram) - it had three "feet" on the inside radius of the gasket - like the picture of the part on marineengine.com.

I also did not have the OMC float height checking tool - so I did make sure the float was parallel with the carb body when inverted. When I primed the fuel line, the bulb got very firm in less than three pumps - so I was hoping this was a sign that the float, needle and seat were working properly. Thank you!

Mike

 

[mixin]

Re: Johnson 30hp running very rich after carb rebuild

When you say you overhauled carb/s, did you remove core/welch plugs? did you allow them to soak for 24 hrs? were they rinsed with fresh water and then blown dry with compressed air including any and and all orifices? Were the carb/s 100% taken apart? If not, I would go back and do it again. Just my 3 cents worth. BTW, Running in tank or can, it will smell more rich that running it on muffs or in the lake!

Thanks so much for your reply!

The carb looked very clean inside with no buildup anywhere, so I did not remove the plugs to clean behind them. It seems this carb is coming back off either way - so I will remove the plugs and clean behind them then for good measure.

I did not have compressed air at my in-laws, so I could not blow the carb out to dry it like I have done on my motor.

It was more than just smelling rich, it would not run under 1,500rpm without stalling, it was mosquito fogging, eye burning rich - LOL!

Thanks again!

Mike

 

[fmalott]

Re: Johnson 30hp running very rich after carb rebuild

i will smell strong when you got it in a barrel or drum what ever i think someone mentioned it i'm pretty sure it's still a carb problem you have to find compressed air somewhere like every one said soak for a while poke a wire or something small enough to poke through jets then use compressed air just using compressed air is not good enough you need something to scrape the sides keep in mind don't damage sides. i think 2-1/2 turns is to much i know manual says that but they are just guid lines try 1-1/2

 

[fmalott]

Re: Johnson 30hp running very rich after carb rebuild

if it is the jets still if the jets are pluged you will not get the sides cleaned and you will still have a small hole which will change the fuel mixture my experience is when the jets clogg up more and more the more you have to adjust the carb and when it gets to the stage it won't run you rebuild and clean which means you got to find the beginning setting
GOOD LUCK!

 

[mixin]

Re: Johnson 30hp running very rich after carb rebuild

I found a thread here with a guy with the same problem and symptoms after a carb rebuild - his electric primer solnoid was turned to manual. I will double check that tonight as well. Thanks guys, I will report back.

 

[AlTn]

Re: Johnson 30hp running very rich after carb rebuild

it looks like a plastic top carb for the 30 hp...on other models, those tops have developed cracks, warped, etc....look closely at the top and the low speed mixture needle area

 

[mixin]

Re: Johnson 30hp running very rich after carb rebuild

it looks like a plastic top carb for the 30 hp...on other models, those tops have developed cracks, warped, etc....look closely at the top and the low speed mixture needle area

Yes, it does have the plastic top! I tightened its mounting screws down just until I could barely see the gasket move - so as to avoid cracking/warping. But based on the wear present on the heads of the float bowl screws, this is not the first time this carb had been apart. I will check the plastic top again.

The mixture screw itself looked great, I will check for cracks there as well. Thanks!

Mike

 

[mixin]

Re: Johnson 30hp running very rich after carb rebuild

I stopped at the inlaws tonight to check it out. The primer solenoid was not in the manual mode. There were no visible cracks or irregularities on the plastic top or around the low speed mixture screw. I did not have any time to investigate further tonight unfortunately. Anything else you can think of let me know! Thanks again!

Mike

 

[AlTn]

Re: Johnson 30hp running very rich after carb rebuild

proper sparkplugs and gap?...float is positioned with the tab on the metal arm pointing upward towards the carb body?...link%sync ok?

 

[spit]

Re: Johnson 30hp running very rich after carb rebuild

funny...my 30hp Johnson has been stalling in idle and i just opened up and am cleaning my carb. it was immaculate.

 

[akdiesel]

Re: Johnson 30hp running very rich after carb rebuild

I was having a problem just like this with my 40hp. Would not adjust with the idle screw would only run at 1200-1400 rpm no lower. Found 1 reed was sticking open just a hair. Took it off and massaged it back a little bit and solved the problem. I would bet that is the issue.

 

[spit]

Re: Johnson 30hp running very rich after carb rebuild

quick question about these carbs....
the small inlet nozzle that sits inside the larger tube that the float surrounds. is it supposed to be perfectly in the center within that tube? mine is at an angle and the end of the inlet nozzle touches the edge of the outer tube. '85 30hp seahorse.