77 johnson 115 upper carb spitting

[whitejamie99]

After replacing the power pack, timing base, and stator, it looks like I need to concentrate now on the carbs. I have good compression and a good blue spark at 1/2" on all 4 cylinders. WOT timing was checked using Joe Reeves method.

The boat started but idled poorly on the muffs. It would die unless I kept the warm up lever advanced and would not idle at lower rpms. I noticed that the top carb was spitting fuel. While the engine was running I would pull the spark plug wire on each cylinder and you could hear the cylinder drop out on all but cylinder # 2. Does the top carb feed this cylinder and I'm running lean or not at all on # 2? What tests can I run to check for fuel feed to this cylinder? I will rebuild both carbs once my carb kits arrive but I would like to make sure.

 

[Daviet]

Re: 77 johnson 115 upper carb spitting

If the fuel is spitting OUT of the front of the carb it sounds like a reed plate is not sealing shut, something holding it open or it may be broken. If you pull the carb, you might be able to see the reed plate. You might have to pull the plate cover for a real good look.
I would correct the spitting problem first and then tackle # 2 cylinder problem, they may or may not be be related.

 

[whitejamie99]

Re: 77 johnson 115 upper carb spitting

Thx - I am pulling the carbs this evening. Reeds were in good shape last season and the boat has only a few hours on it since. Its not so much spitting as its just leaking around the front. The motor does sneeze at low RPM. I can see fuel in the top carb but not the bottom.

 

[tashasdaddy]

Re: 77 johnson 115 upper carb spitting

you have 2 2 barrel carbs. yes the top carb feeds 1 & 2, sounds like you have clogged orifices in the top of the carb. that is not allowing the fuel in. look at the engine side of the carb barrel, open the butterfly. on the top you will see several small holes, this is how the low speed fuel gets to the motor. you have high speed jets on each side of the bowl, and low speed jets on each side of the carb body.

 

[whitejamie99]

Re: 77 johnson 115 upper carb spitting

So a thorough cleaning and rebuild is in order. This will be my first carb rebuild - usually I let someone else do it. Already printed out the top secret file.

 

[whitejamie99]

Re: 77 johnson 115 upper carb spitting

Took the carbs off. They are not the stock carbs for the 77 115hp. The number on the carb is 317470-d2. It is the same # on both. Does anyone know the year and motor these carbs belong? It may explain some of my problems with this setup.

 

[tashasdaddy]

Re: 77 johnson 115 upper carb spitting

that is a casting number, not the part number.

 

[ENSIGN]

Re: 77 johnson 115 upper carb spitting

The sneeze is from running to lean.The spitting could be a broken or cracked reed,Check them carefully while you got the carbs off.

 

[whitejamie99]

Re: 77 johnson 115 upper carb spitting

From reviewing the parts catalog, it looks like a 73 115 carb. It has the 2 idle passage screws on the front of the carb body. Is this an adjustment with this carb?

 

[Daviet]

Re: 77 johnson 115 upper carb spitting

If you are talking about the orifice on the side below the throttle shaft, it is fixed like the high speed jet, no adjustment.

 

[whitejamie99]

Re: 77 johnson 115 upper carb spitting

No thats not the one. These are two screws on the front of the carb body just below the choke plate but in the casting of the body. See # 27 on the attachment. Hopefully it is not too small.

 

[Daviet]

Re: 77 johnson 115 upper carb spitting

Finally found a picture I could see, that screw is just a plug for the idle passage, no adjustment.
The idle is controlled by the non adjustable orifices on the side of the carb.
What is the model# of your motor?

 

[ezeke]

Re: 77 johnson 115 upper carb spitting

There are no adjustments on the carburetors - all fixed jets.

The only adjustment needed is to synchronize the throttle plates and the choke plates so that they work as and when they are supposed to.

 

[whitejamie99]

Re: 77 johnson 115 upper carb spitting

model # 115etl77

 

[whitejamie99]

Re: 77 johnson 115 upper carb spitting

There are no adjustments on the carburetors - all fixed jets.

The only adjustment needed is to synchronize the throttle plates and the choke plates so that they work as and when they are supposed to.

Thanks Ezeke. Kits are on the way and will clean/rebuild the carbs. The carbs look clean and I didnt find any obstructions in the passageways or the jets. Float valves are both good and core plug area is clean. This is my first rebuild but so far havent screwed anything up.

 

[Daviet]

Re: 77 johnson 115 upper carb spitting

Thanks, just wanted to confirm carb.

 

[whitejamie99]

Re: 77 johnson 115 upper carb spitting

Thanks, just wanted to confirm carb.

Thanks Daviet for your help. The carbs i have now are from a 1973 115hp according to the parts manual. I remember buying them 3 years ago but cant find the paperwork. Original carb had a casting break off near the choke and jet passage threads were screwed up from previous owner.

woohoo post # 100 for me.