Johnson 50 idling and bogging down issues

[Copilottruman]

Thanks in advance for any help. Last week on the way back in from a fishing trip while at full power my outboard out of nowhere started bogging down and then soon after cut out. The sound it made when it died was similar to the time it died a week before that. However the first time it died it was remidied by unscrewing the fuel tank vent all the way. This time that didn't work. The engine will now only stay started when I rev it up in neutral but when I lower the rpms to put it in gear it dies. Thinking that something might have gotten sucked into a carburetor jet I removed the carbs and took them apart spraying them down with carb cleaner and compressed air and reset float heights (per other iboats topics). After reinstalling them, cleaning them did nothing to help the problem. Some other things that I've checked are:

My idle adjustment screw is all the way in.
The primer bulb gets hard and stays pretty hard after running. When I hit the electric choke when running it dies.
The fuel pump screen is completely clean.
Fresh gas.
New plugs within the last month.

I'm at a loss on what it could be and the engine was running great and started right up every other trip. I'll post a video of what it sounds like on a pair of muffs.

https://youtu.be/k1oHwZX0Csw

 

[oldboat1]

What motor do you have? Might be a fuel pump diaphragm -- down and dirty test is to use the primer bulb when the engine wants to stall out.

Your idle adjustment needle should not be fully closed, if your motor has a needle. On a non-adjustable idle mix, the hex nut would be fully closed.

 

[Copilottruman]

J50BELCNR. I don't think this outboard has adjustable jets. Which hex nut are you speaking of?

 

[oldboat1]

My idle adjustment screw is all the way in.

https://youtu.be/k1oHwZX0Csw

What is your reference? Are you referring to carb or throttle?

 

[Copilottruman]

http://www.marineengine.com/parts/j...urer=Johnson&section=Cylinder+&+Crankcase

part 51. Im pretty sure it doesn't have much to do with this particular problem. I just have always had it screwed all the way in to keep her idling.

 

[oldboat1]

throttle idle speed screw (51).

Numbers 30 and 36 (carb diagram) gives you some access to the idle passages in your carbs, and it wouldn't hurt to try some carb spray after removing the screws (screws on yours, not hex bolts). They need to be snug, but don't need to really get after them. (Number 12 at the bottom will give you some access to the h.s. jet, and can try some carb spray there too.)

Try the primer bulb and see if you can keep it running. If that makes no difference, my first guess would be carbs (disassembly and full cleaning and rebuilding).

 

[Copilottruman]

I disassembled the carb and blew into all of those ports the other day and they were quite clean. Im going to order a fuel pump repair kit since it is quite cheap and seems like an easy repair. Would the primer bulb itself cause this problem?

 

[ondarvr]

Squeezing the primer bulb will let you know if the fuel pump is the problem instantly, and there's no charge.

 

[Bosunsmate]

Have you checked compression and or done a drop test? Might be running on one cylinder

 

[Copilottruman]

I can do a compressor test today. What is a drop test and how would you find out if it's rubbing on one cylinder?

 

[Copilottruman]

Did the bulb test and nothing happened. Looked up how to do a drop test. I pulled the bottom park plug wire and it died instantly. Pulled the top wire and it continued to run. So I'm assuming the top cylinder is my problem? How can I go about isolating this problem? In the past I've had some wiring issues so is there a way to see if it's the wires or a coil that needs to be replaced?

 

[Copilottruman]

Also, I just replaced the spark plugs and gapped them correctly. Then I completely switched the spark plug wires and did the drop test again to try and see if it was the spark plug wire. Still when the top cylinder wire is pulled it continues to run.

 

[oldboat1]

If you haven't done it already, get an open air adjustable spark tester and check for spark -- should see about 1/2 inch when cranking (remove and ground the second plug as well, keeping spark away from the plug holes). The drop test tells you if you are losing spark when underway, higher rpms, components heated up, etc. A routine spark test tells you whether the ignition components are producing enough to fire the plugs (i.e., new plugs or regapping not the issue).

 

[Copilottruman]

I tested and am not getting any spark to the top cylinder. I did a multimeter test per the oem manual on the two coils and it passed. This leads me to believe that it is a power pack problem. I tried to follow the instructions on how to test the power pack. I got what seems to be a fail on those tests however the instructions are a bit vague and im not sure if I did it correctly. The manual says set to Negative and 500 on the multimeter but im not sure how to get it to read negative. If its not spark plugs, high tension wires, or the coils is it safe to say its the power pack? I was told by a local marina that it is common?

 

[jakedaawg]

Negative and 500 refers to settings on a stevens instrument co. Peak reading voltmeter

 

[jakedaawg]

No Title

Like this one.

 

[Copilottruman]

so im assuming a multimeter can't do what that thing does? Is it safe to assume its a power pack.. they're quite expensive.

 

[jakedaawg]

so im assuming a multimeter can't do what that thing does? Is it safe to assume its a power pack.. they're quite expensive.

No, most multi-meters cannot do it. There are a couple from fluke i believe that have a dva setting but ifnyou didnt pay a months mortgage for it it is doubtful.

Detail what tests you did. Have you ruled out everything else? (Stator, trigger, coils, key switch and kill switch) if so, packs do go bad.

 

[Copilottruman]

I've replaced spark plugs. Tested with a multimeter the coil wires and the primary and secondary potions of the coils. I have a new key switch. I don't think it's the kill switch because the engine starts it just runs on one cylinder per the drop test. Now I'm just debating whether to replace the power pack or stator. However I don't think I feel comfortable taking off the fly wheel so I'm praying it's the power pack.

 

[ondarvr]

Did you move the coils from one cylinder to other one, or just the wires. Coils can easy test as good, but fail in actual use.