1972 johnson 115 carb adjustments

[Cmrauto]

I can't find any Idle mix screws on this thing, Do they exist?? Has what appears to be two carbs of 2 barrels each sitting one carb on top the other. I believe I am within a year or two on the age of this 115 johnson<br /><br />thank-you-all<br />Rick

 

[22WRF]

Re: 1972 johnson 115 carb adjustments

Depends on the type Carb and one year makes a big differance.<br /><br />1972 Type IVB has fixed jets.<br />The IVA has Fixed High Speed Adjustable Low Speed <br />If you can't find the low Speed it's because they are fixed.

 

[OBJ]

Re: 1972 johnson 115 carb adjustments

Hi Cmrauto...Please post a model number....there was no 115hp in 1972. Look on the trasom bracket for a tag with the model and serial number or on the engine block for a soft plug with the model number on it. Thanks!

 

[Cmrauto]

Re: 1972 johnson 115 carb adjustments

mainly i was hoping to readjust the idle mix on this because it intermittently stumbles when idling. When warmed up seems worse as once in a while it bucks and stalls out. I thought i saw a bit of a backfire through the one carb as it happened but can't confirm as did not notice this again. If I pull a wire and run on three I still get this missfire once in a while, about every 5 to 20 sec. I noticed the coil on the stator is or has leaked out but it starts real well and has a good strong spark, compression is 165 to 170 on all cylendars If it has a fixed idle mixture how can I iscolate the fuel?<br />It is a 1972 115 hp

 

[Cmrauto]

Re: 1972 johnson 115 carb adjustments

Sorry I am told it is a 1972 115, the only number I can get from the block is 129222, the motor is not original to this boat

 

[Cmrauto]

Re: 1972 johnson 115 carb adjustments

when I say I pulled a wire and ran it I went through all of the wires one at a time

 

[OBJ]

Re: 1972 johnson 115 carb adjustments

Hi CM...the last 115hp built with low speed needles was 1970. No 115hp's were built in 71' or 72'. In 1973, the 115s' had fixed low speed jets...no adjustment needles. The needles would be readily apparent if they are there. I would conclude that your engine is at least a 1973 or later.<br /><br />If the stator coil is or has leaked, you would do well to replace the assembly before it fails altogether. Coils leaking mean they are getting hot. This coil maybe causing your idle problems.<br /><br />If you have a service manual, run through the sync and link plus idle timeing adjustments. Make sure your throttle plates are in sync.<br /><br />One more thing to look at....with the motor at idle, check for any blow back from the carbs. You can check this by holding a piece of tissue paper in front of the carbs. The tissue should be trying to get sucked into the carbs. If it blows out, you may have a cracked or damaged reed. This would affect the way the engine idles. Blow back would also be apparent by a lot of fuel mix laying around the front pan.<br /><br />Keep us posted and Good Luck!!

 

[flykr2s]

Re: 1972 johnson 115 carb adjustments

I have a 1973 115 model 115ESL73. There are no idle adjustment screws on the carbs. Each carb has two low speed and two high speed orifices. These regolate the flow and are not adjustable. The needles on these carbs are fixed and are not adjustable either. The two carbs are linked together an work in unison with each other. There is one idle adjustment screw stop on the throttle linkage on the side of the motor. Hope this helps.

 

[Cmrauto]

Re: 1972 johnson 115 carb adjustments

I decided to take some time and check the resistance on the coils and found one was open circuit on the secondary so I replaced it. The idle problem is still there, every once in a while it bucks and eventually bucks hard enough that it stalls out. Still not having any luck a local marine tech tells me not to worry about the oil coming out of the coils because it costs about $4oo bucks, he believes they aren't worth changing unless it wont start.????