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1996 Johnson 150 faststrike stalls under load

M

Mixen22

New member
I have a 150 faststrike (j150gledb) that stalls when under a load. The motor ran great in the first part of the season and then one day when I went to put it into gear the motor would stall out. This problem started around a month or so ago and I have been attempting to troubleshoot with no success. Compression and spark both checked good on the motor. When I run it on muffs it also runs perfectly fine in neutral and in both forward and reverse. When in the water it will run fine in neutral with the ability to rev the motor. When in gear however it will almost always stall immediately. Neutral idle in water is around 750-800 RPM, when in gear it drops to roughly 600. To me it seems as if the fuel is not being properly delivered to the motor for it to run under a load. I have inspected the fuel pump and all the gaskets and diaphragms look good. I have also bled the fuel and oil lines to ensure no water was trapped in the lines. When running she smokes pretty bad, which leads me to believe that the proper 50:1 fuel/oil ratio is not being achieved. I think I am getting proper oil levels just not getting the right amount of fuel. My next step is to take apart the carbs for a cleaning/rebuild. I was wondering if anyone on here has experienced anything like this with a similar model motor and if I am taking the correct steps in my troubleshooting process. Any replies and information would be greatly appreciated.
 
Running on muffs won't tell you much. Revving in neutral on the water doesn't either.

Lots of smoke is a good indication fuel mix ratio is not correct. A full rebuild on the carbs is a decent thing to do, especially if it hasn't been done in a long time. Does your primer bulb go flat? One possibility is a restriction in the primer bulb or the antisiphon valve in the fuel tank.

KJ
 
It doesn't necessarily go flat, but it does not keep pressure. I can squeeze the bulb to have pressure build back up but it will start to go soft again very shortly
 
racerone said:
Running in gear on the muffs is still nuetral !-------------Propeller does not do any " work " moving air !
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Running in gear on muffs is not the same thing as neutral. Indeed the prop does not do any work because it is not displacing water and has no sort of back pressure, but you still can verify that the gears are engaging and I'm fact that your prop is spinning while in gear. I also was not using this as any sort of check, just clarifying that I understand the problem is when the motor becomes under a load, or trying to get it into gear while in the water. That's where my issue occurs.
 
Prop does not do any work running on muffs.----Does spark jump a gap of 7/16" on all leads , yes or no ?-----If bulb goes soft with motor NOT running there may be a leaking float valve in a carburetor.----If carburetor bowls are plastic they may be warped.
 
racerone said:
Prop does not do any work running on muffs.----Does spark jump a gap of 7/16" on all leads , yes or no ?-----If bulb goes soft with motor NOT running there may be a leaking float valve in a carburetor.----If carburetor bowls are plastic they may be warped.
Click to expand...

Spark checked fine on 7/16. I have not checked the bulb while the motor was not running. I'll check that. I planned on rebuilding the carbs so when I do that I will be replacing the floats and inspecting the bowls. The other thing I plan on doing is replacing the fuel lines for piece of mind. That way if there is any obstruction then I know it will be cleared.
 
Mixen22, have you performed a compression check as we discussed on another forum?

I notice spark will jump a 7/16 gap and that is great. As mentioned in our other discussion, it is going to be difficult to get it running properly without the factory manual. I can't stress that enough. There is a series of checks that are hard to convey in a series of posts on a forum. This factory manual will be your best tool.

Good luck and keep us posted, I learn something here almost every day.

208
 
208Adventure said:
Mixen22, have you performed a compression check as we discussed on another forum?

I notice spark will jump a 7/16 gap and that is great. As mentioned in our other discussion, it is going to be difficult to get it running properly without the factory manual. I can't stress that enough. There is a series of checks that are hard to convey in a series of posts on a forum. This factory manual will be your best tool.

Good luck and keep us posted, I learn something here almost every day.

208
Click to expand...

I did get a copy of the manual and that's what I've been troubleshooting off of. I did run a compression test and all cylinders were within 10% of each other (around 95)
 
Excellent,
If this is a factory manual, near the front there will be a section pertaining to annual inspection that has a series of checks and adjustments to be performed.
If you follow this in order and still have issues, go to the section where recirculation system is located and perform those checks.
This should be an OIS 2000 ignition system engine, maybe you can find someone locally to set your idle and wot timing. After idlemixture needles are adjusted, idle timing sets idle speed. (all spelled out in the manual)

Take this in small bites, go in order, don't get sidetracked and you will get it working.

Good luck and let us know how it works out

208
 
208Adventure said:
Excellent,
If this is a factory manual, near the front there will be a section pertaining to annual inspection that has a series of checks and adjustments to be performed.
If you follow this in order and still have issues, go to the section where recirculation system is located and perform those checks.
This should be an OIS 2000 ignition system engine, maybe you can find someone locally to set your idle and wot timing. After idlemixture needles are adjusted, idle timing sets idle speed. (all spelled out in the manual)

Take this in small bites, go in order, don't get sidetracked and you will get it working.

Good luck and let us know how it works out

208
Click to expand...

Thanks. Will do!
 
Ok so I removed the carbs and throttle plate last night so I can start breaking them down, cleaning and inspecting them, and looking into parts that may need replacing other than the gaskets. I made it through the starboard side last night and all 3 looked pretty damn clean when inspected. Will do the port side tonight to make sure they look good as well. The only thing I really noticed was a pinkish gummy like substance coming from where the fuel manifold hooks into the throttle plate. it almost looked like some sort of lubricant but it was not on every connecting port so it seemed out of place. Is there a good way to clean the fuel manifolds considering they are not available for purchase anymore?
 
I use Engine Tuner then flush with alcohol then blow with low pressure air. Use a syringe and check that there is flow through the needle sized passages.
 
https://photos.app.goo.gl/II8JcWPDpRkRwCBI2

https://photos.app.goo.gl/7f2qGnCvkv0ivQbe2


https://photos.app.goo.gl/2fSz8Wp264UYo5513

IDK if these images will work or not. They are links made from my Google images on my phone. This is the residue I am concerned with. You can see how the residue is on both the throttle plates and the fuel manifold, but it is not every port. If it we're some sort of lubrication or sealant it would make sense but I would think it would be on every port and not just some of them. If anyone has any info on this I'd appreciate it if you could share it.
 
As far as other things I noticed while cleaning the carbs is one of the Phillips heads that holds one of the carbs was loose. Like only hanging in by a single thread loose. I don't know if that's so much of a problem though considering the mounting bolts for the throttle plates are right next to it. All of the seals were unbroken and looked pretty good. I will be replacing them, but there was nothing to warrant too much concern. One of my carb bowls was completely dry (bottom one on port side) I'm thinking the float needle and seat was not opening properly and causing a lack of fuel into the bowl. Either that or the jet from the fuel manifold could be clogged. These were the only issues I saw.
 
so it has been a while but I was waiting on funds for parts and such and finally have an update. I replaced the gaskets on all 6 carbs as well as cleaned the very thoroughly. I also replaced the fuel rails for peace of mind and the fuel lines running from the tank all the way to the motor. The water fuel separator was also replaced. It seems like the motor is running much much stronger. However, when in forward gear it still wants to stall out around 1100 RPM. This does not happen when in reverse, only in forward gear. I know I need to re-sync the carbs since cleaning them out as the idle RPM was around 500-600 when in gear and around 800 in neutral. I am just puzzled as to why it would want to stall in forward. But progress is progress as I can cruise around at like 5 mph which I was not able to do before.
 
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