1995 Johnson 150 OceanRunner Idle Stall/Runs past 1500 rpms

[No_Regrets]

I have a 1995 Johnson 60 degree oceanrunner and I've been having an idling problem for quite some time. She starts up no problem when you hold in the choke, and you have to keep pushing in the choke every 3-5 seconds for it to keep running. Stop what you're thinking, here is everything I have done:

Carb job on all 6 carbs plus the throttle body, by me and a mechanic. Cleaned out all orifices with a welders tip and blew it all out, never really was that dirty to begin with.
Every cylinder has spark, I tested by at first disconnecting each bank of plugs and seeing if the engine would run on just one side, and it did, then I actually performed a spark test on each cylinder with a spark tester.
Every cylinder has 120 +/- 3 psi compression.
Replaced power pack
Replaced voltage regulator
Replaced fuel filter, fuel line, bulb before the first carb job
Gone through most grounds and ensured they were not corroded.
Hooked up an electric in-line fuel pump to check to see if there was a problem with the anti-siphon valve or fuel pickup tube, still had same problem.
The plug to the power pack from the stator read 58 ohms for the orange pair and 560 for the brown to brown/yellow and brown/white to brown/black. My peak voltage going from the three orange spark wires read a little over a hundred volts for each one, this could be off though because I'm using a non-electronic peak voltage tester. My battery has been around 13 volts each time I use it, it stays on a trickle charger I disconnect before I start the engine.
I checked the vacuum lines as best as I could with a vacuum meter, the most I saw was around a 2 psi vacuum in the lines on the side of the block. I put my finger over the pulse line going to the vro pump and it coughed back some pretty hot vapor. I couldn't find any values of what they were supposed to be so I came here.

I'll describe a brief history of how I got here. My lower unit went out and I kept her out of the water for around 6 months before I replaced it, without thinking I started it up with the old gas and put it in the lift from the ramp. After that I sucked out all the bad gas, and replaced with fresh, treated gas. After that, she would only idle, 4 of the 6 carbs were not putting gas in the cylinder so I cleaned them out and they all ran. After that my safety clip switch broke and I thought it was an electrical problem, hence the voltage regulator and power pack. That took me over a couple of months in the summer heat and I took the gas out again and replaced with fresh, treated gas. I can run around anywhere I want to, at what feels like a higher top speed from before, without any missing, but as soon as I slow down I have to use choke to refrain from stalling.

So, thank you anyone for helping, believe me I have exhausted the search bar.

 

[boobie]

Re: 1995 Johnson 150 OceanRunner Idle Stall/Runs past 1500 rpms

I promise, I won't think. LOL.

 

[daselbee]

Re: 1995 Johnson 150 OceanRunner Idle Stall/Runs past 1500 rpms

Ummmm.......I know you don't want to hear this, but you missed something in the carbs/throttle bodies.

You have clogged idle passages somewhere in the carb system. Most likely cause.
Did you absolutely clean the micro sized holes that open up into the side of the venturi right at the throttle butterflies?
Inspect closely, you will see.
Did you clean the brass idle pickup tube (small one) that extends down into the bowl? Clogs occur there.

When you press the key in for primer, you are shooting gas straight to the cylinders, bypassing the carbs.
Says to me that the carbs are not drawing gas up from the float bowl, BUT ONLY AT IDLE. Right?

So clean the idle circuits. The whole idle circuit for each cylinder.
The black carb bodies are only part of the carbueration system.

 

[No_Regrets]

Re: 1995 Johnson 150 OceanRunner Idle Stall/Runs past 1500 rpms

I took off the black cover over the idle jet/needle assembly on port side since you don't have to take all 3 carbs off. Lo and behold it was clean as a whistle, what did catch my eye however is how large the needles were, I had recently had to replace one on the starboard side because I dropped it while I was cleaning the throttle body. I guess the previous owner replaced alot of them because they were different colors/ different sizes all around. I had reset all of them to the two turns out position after cleaning the throttle bodies so I said screw it and turned all of them 5 full turns out and it cranked over instantly.

I should of known you never know what the previous owner does to engines before you get them.