2007 15HP Johnson - stalls at low speed.

Starts fine with choke engaged. After taking choke off it will begin to stall after a short time. Will keep it running by engaging the choke again and then disengage choke and it will continue the same sequence - begins to stall engage choke and it runs for a short while and start to stall again. Runs fine at above starting and trolling speeds. Leaning toward taking carb off for a cleaning, but due to the symptoms, I don't think that is the problem. Appreciate any input.

Do the carb. Sounds like a problem in the low speed circuit.

OK - waited for a carb kit to arrive. It has done so and I looked at a 2007 Johnson Service Manual for the 9.9 and 15 HP Model. The Model # on mine is J15RSUA.

On page 108 o this manual under Fuel System / Carburetor Service it states "This carburetor uses a tamper resistant low speed needle and body cover assembly" "The needle valve is NOT removable from the cover and is adjustable within a limited range". "If the needle is turned for any reason, it should be retuned to its original location".

If I am experiencing a problem on the low speed side of carburation, how do I clean out the low speed side? On page 114 of manual It states"Adjustment of the tamper resistant needle valve requires a special Torx Screwdriver P/ 351204 - while I did not try to screw it out. it appears that a T15 Torx Head screwdriver does fit this, Is this so? The manual does not state what the original calibration settings are, is it seated and 1 1/2 turns out?

Thanks for the input and any advice on this matter.

Does anyone have any input on my last posed questions?

Am I to assume that there are no outboard motor mechanics on this site that know anything about this tamper resistant low speed needle valve from my questions posted on 4-14-15?

Any pictures of this valve ?-------Newest motor like that in my inventory is a 2001 model.

OK - took apart carb and began to clean. When I got to the special tamper proof low speed valve (did use the special torx screwdriver that was made for this), I went to seat the screw against the back wall to determine how many turns out it was from the seated position it was. What I found was that it was seated when turned counter clockwise. When this torx screw was moved clockwise, It acted as it was seated again. I find it hard to believe that the factory setting for this would be seated when turning to the counter clockwise position. Does anyone know the factory setting or this tamper proof low sped needle? ill attempt to post pics of this tamper proof low speed needle
. Tried to upload pics with no success.

Anyone - still looking for help. Just to try and include all info on this I looked at this tamper proof needle valve assembly again. Because I don't want o force anything it appears to me that the adjustment screw on this low speed needle will not come out. As I stated in previous post, it is already seated when screwed counterclockwise and this is the position I found it at and it seems to set again when screwed clockwise. Range of adjustment from counterclockwise to clockwise is approximately 1 1/3 turns. Does anyone know if this can be disassembled further for cleaning? Does anyone know what the factory setting is as can't believe that it would be seated at the counterclockwise position.

Pease help - walleye season opener is in 4 days.

Is anyone aware of another Forum where I can get an answer?

Try tinboats.net.

Good luck.

CMOS

Answer this question ---------Top of this page you will find ---ENGINE DIAGRAMS---Look your carburetor up on this and tell us the ITEM # of the part you are trying to adjust !!!

For my 2007 RSUA 15 HP according to the carb parts diagram there is no low speed needle, it comes in he Carburetor Cover Assembly. I purchased a 2007 Service Manual for the 9./15 HP Johnson 2 stroke. On page #108 under the Header Disassembly it states: IMPORTANT: Changing original factory fuel mixture calibrations beyond the limits allowed by the tamer resistant device is a violation of federal law. Changes to the original design or adjustment limits become the responsibility of the servicing technician and/or owner. The following procedures must be followed EXACTLY to ensure compliance with emissions standards. This is followed by anther IMPORTANT: This carburetor uses a tamper resistant low speed needle and body cover assembly (except 10HR models). The needle valve is NOT removable from the cover and is adjustable within a limited range. If the needle is turned for any reason, it should be returned to its original location.

In this carburetor section of the manual there is no further info. I find the info that I posted in the previous paragraph confusing as it states "is adjustable within a limited range" but gives no adjustments to make, but in the next sentence it states "If the needle is turned for any reason, it should be returned to its original location". But it never states what the original location is.

As I stated in a previous posting, I found that this needle was seated at a counter clockwise position. When turned clockwise it seated again after approximately 1 1/3 turns.

What other trouble shooting has been done on this motor ?---------Compression test done ?------Checked the flywheel key ( timing ) on this motor ?

No to both questions in last post.

Sorry , but folks often pick on the carburetor when they start fixing a motor.----Did you find any dirt / gumming in the carburetor ?---Fact is that very little goes wrong with them.----------Do a compression test first.-------Has the waterpump been looked at ?

Got impatient awaiting information on that tamper proof low speed valve, so last night took the carb apart and gave a through cleaning. Upon doing disassembly, I found that there was no gasket under the fuel inlet valve (could have this caused the problem?). When I ordered the carb kit I also bought new spark plugs QL82C's and installed them. The plugs I took out of the motor were Champion L77JC4's . Started on the 2nd pull and purred like a kitten.

This motor was purchased used 2 years ago from a rowing club that used it on a safety chase boat. I'm sure that most of the motor running time was at a idle speed so carbon build-up may also be an issue. Took steps to resolve any of these issues.

Thanks to those that took the time to help point me in the right direction, but I still would like to know what the adjustment range of that low speed is - I left it in the position that I found it in - seated counterclockwise.

Gonna try one more time to upload a picture of that low speed valve as sits on the carb. Once again with the pic - no success.

I have been looking for something about this for a while, I have the same model, J15rsua and the same issue. I changed the spark plug wires/ and plugs and this issue happened. I've cleaned the carb and found that the gasket under the fuel inlet valve was missing also but I don't believe that is an issue. I have checked the compression - 115 in top and 110 in bottom. I have also opened the fuel pump and that is fine. I have been lead to believe it has to be that stupid tamper resistant screw.. I hate this model carb. If your plugs fixed the issue I think maybe I need to look into that.

Hi. I had 2006 johnson 15hp with that tamper proof slow speed needle thingy. I called evenrude dealler and they sell special tool so you could adjust mixture screw. It cost around 25 pound stirling in UK so should 25 bucks in USA. That was done on the 2005 to 07 motor due to polution regulations.
Hope it helps.