1999 Johnson 25hp very bad idling problem

[Michael leblanc]

Ok I clean carb set float and mixture screw but it still jumps and skips and backfires just at idle runs awesome at wot new fuel line and I have it hooked up straight to fuel pump no connections so it don't suck air any other ideas from you guys would really help

 

[Bosunsmate]

Have you blown carb cleaner under pressure down all the little passages? (and watched it come out the exiting holes).
As just a little speck of crap in one of them can cause a gum up and those exact symptoms.
Soaking in carb cleaner never really does the job in my opinion

 

[racerone]

Did you adjust low speed mixture after the first start up, yes or no ?-----Has the adjustment on the throttle rod that goes to the towershaft been tampered with ?

 

[Redstern]

I want to think that is just the rough idle of a 2 stroke, but I would have to hear it to know. But assuming it is a problem, it probably has something to do with your low speed jets. Does you carb have separate mix screws for low and high speed? If you have more than one carb, did you make sure to balance them? You can also try cleaning them again and try to spray some cleaner through the low speed jets with pressure.

 

[Michael leblanc]

I clean carb with carb cleaner and and blew out jets ...and yes I set lean/rich screw 1-1/2 out and the little knob at the end of the tiller doesn't work it just turns and turns I'm not sure what's it for

 

[Michael leblanc]

Never put new plugs yet and never check them in a while you think it could be foiled plugs

 

[Michael leblanc]

It's 1 carb and I have fixed high speed jet and just 1 lean/rich screw to set at idle and I set it to specs and it's still splitting and sneezing and when it sneezes puff of smoke comes out like it would be loading up but idk I have it only turned out 1-1/2 so it's just confusing me

 

[Michael leblanc]

No Title

 

[racerone]

There is a number posted for the initial setting of the low speed mixture.-----The motor will start and run with that setting.-----Then the owner / operator must adjust the low speed mixture to suit once motor is running.--And was there any adjustment made on the rod that goes to the tower shaft ??

 

[Michael leblanc]

Ok idk what a tower shaft is but I know how to set the mixture screw (1/8 of a turn either in and out to get smooth idle) but it's not working and the needle is brand new so there's no damage there that's why I'm confused

 

[racerone]

Can you find the thin metal rod that goes to the back of the motor ?----OK---Now post a picture of the adjustable stop on that rod.--Post a picture of that stop with tiller handle at slowest idle position

 

[Michael leblanc]

Ok let me go check

 

[Michael leblanc]

It's not letting me load picture

 

[Michael leblanc]

Ok since it it's not letting me load the pictures I'll explain the rod going to the side the motor the lil stopping collar is about 1/2 inch from the block

 

[Michael leblanc]

No Title

 

[oldboat1]

Offhand, that looks to me like a 9.9 carb. Sure you have the right carb?

 

[racerone]

And here I thought that most 9.9 carburetors used a choke flapper.--------Do not see one on here !

 

[Bosunsmate]

Have you tried putting your hand or a piece of cardboard slightly over the front of the carb and then increasing to cover it up and seeing if that stops the sneezing?
That adds more fuel and so indicates if thats the problem

 

[Michael leblanc]

No it's a 25hp carb that's a pic I found online not my actual carb ...no I never tried covering the throat of the car to see if it stops I can try it tomorrow...on another note I took my plugs off and they were black

 

[oldboat1]

Ah. Carb throat looked small.

(Thx. R.).

Try leaner first (clockwise), from initial setting.