1990 Johnson 15hp only start with carb disengaged

[sinkingscones]

Model: J15RESR
Previous owner couldn't get it to run, I cleaned carb, swapped plugs and wires, and replaced carb body cover which I found was cracked. Only thing left is cam roller missing a rubber sleeve I haven't fixed. Running 50:1

With needle idle set at 4 turns out and choke engaged (butterfly closed) I can't get it to start. It'll only start with the choke disengaged (butterfly wide open).

I'm wondering if it's running too rich, not sure what to check next.

 

[Crosbyman]

what cleaning did you do on the carb.....sprayed carb cleaner or full take down and rebuild ?

 

[sinkingscones]

what cleaning did you do on the carb.....sprayed carb cleaner or full take down and rebuild ?

I sprayed it down and put it back together, but also the plastic carb body cover was replaced since it was cracked so the idle needle and the cam barrel had to be adjusted.
Also while it's running on neutral with tiller twisted towards start, is it supposed to die off when I twist it back the other way?

 

[Crosbyman]

the other way being SLOW... yes some engine use the throttle to shut down some have a kill button... as long as it idles nide in gear you should be all set

seems to have IDLE STOP adjustments(Screw spring...) see parts diagram or user manual for adjustments or... wait for expert here to comment

 

[racerone]

I have learned ( long ago ) that trouble shooting on outboards starts with a compression test.-----Post the numbers here.-----Walked away with a low hrs 1964 model 5.5 Johnson from an---- AOMCI----meet.-----Half a dozen folks looking at it basically declared it SCRAP because of low compression on top and bottom.--------I said right there that the head gasket was blown.-----When I got it home I took the head off and there was the head gasket blown between cylinders.

 

[jitterbug127]

4 turns out is too much. I've always started at 1 and 1/2.

 

[sinkingscones]

the other way being SLOW... yes some engine use the throttle to shut down some have a kill button... as long as it idles nide in gear you should be all set

seems to have IDLE STOP adjustments(Screw spring...) see parts diagram or user manual for adjustments or... wait for expert here to comment

I have the red kill button at the end of the tiller hande so I'm assuming its probably not supposed to die when it's turn fully to the opposite end.

 

[sinkingscones]

I have learned ( long ago ) that trouble shooting on outboards starts with a compression test.-----Post the numbers here.-----Walked away with a low hrs 1964 model 5.5 Johnson from an---- AOMCI----meet.-----Half a dozen folks looking at it basically declared it SCRAP because of low compression on top and bottom.--------I said right there that the head gasket was blown.-----When I got it home I took the head off and there was the head gasket blown between cylinders.

I think they're close enough to not be a problem.

 

[sinkingscones]

4 turns out is too much. I've always started at 1 and 1/2.

4 turns out is the suggestion from the service manual but I've tried it all, it doesn't affect anything. Seems to be running too rich, spark plugs are wet and today it suddenly only starts with throttle open.

 

[sinkingscones]

Is this too much oil for 5 mins? Almost looks like a leak

 

[saltchuckmatt]

No.

In a barrel that's what they look like. What it wants is to be taken out on a boat.

 

[OptsyEagle]

"Only thing left is cam roller missing a rubber sleeve I haven't fixed. "

Without that rubber sleeve I would think you would be having problems synching the carb to the timing advance. Also, the throttle starting positions would be all messed up. I would fix that first. For a band aid fix I found that 1/2" pex pipe almost fits around that sleeveless carb roller perfectly. I took a round file and filed out the inside a little so the pex pipe fit better and held it on the carb with electrical tape and it has been working for me that way for 3 years now.

Anyway, I suggest you fix that and then make sure your carb is synced up by ensuring the line or arrow on the throttle cam is in the middle of that fixed roller just as the throttle cam touches the roller.