1995 130HP Johnson 2 Stroke shutting down

Hi guys, I just serviced my 1995 130HP Johnson 2 Stroke, bought carb rebuild kits for all carbs, cleaned them thoroughly and changed all parts that came with the kit, also the floaters. Put everything back together again, and... now the engine has gone all weird. It starts, then dies out after a few seconds. Also tried revving it up, which sometimes it actually does, but then it still dies on me after a few seconds. There was a brief period today that it stayed on, but then it started revving up all by itself to high rpms, then slow down to a minimal rpm, and then it would go to high rpm, and back down, etc, without me touching anything, until I turned it off. Also I tried putting it in gear while the engine is (still) on, which also makes it die out immediately. Actually, that last part was what made me service the carbs in the first place, but things only got worse. What to look for? Thanks guys.

Plugged fuel line? Primer bulb in backwards?

Need to inspect your carb work, the gaskets and mounting o-rings. Make sure floats are set correctly and not upside down.

Thank you guys for the advice - I am taking the carbs off again today and will disassemble them again - I must have made a mistake somewhere there. I will repost here with findings and results.

What trouble shooting was done to lead you to believe--- " It must be the carburetors " here ?-----Did you find anything wrong or dirt in the carburetors ?-----Start with a compression test , post the numbers.----VRO in service and tested ?----Test for strong spark ( 7/16" ) gap on a test device.----Water pump impeller replaced ?0000Perhaps test run with another hose and fuel tank.

Hi Racerone, I have done major work on this engine, last year changed the CDI and the stator, spark leads and sparks, both thermostats, and it had been running fine all summer of 2020. Only lately the engine would die out on me once I put it in gear and go forward. However, while NOT in gear I could rev it up as much as I wanted. This led me to buy carburator rebuild kits, which I have fitted a couple of days ago. While I was at it, I also changed the complete waterpump with a total kit, including the impeller. - and then the weirdness started. So, the only thing I can think of, is something went wrong with the carbs. I think I may have done maladjustments with the floaters.

Ok, so I redid all the carb work, and indeed found that the floaters needed better adjustment, plus the packing between the floater unit and the carb had not seated well for two of the four carbs. So that is now corrected, the machine starts, but the persistant problem I had in the first place remains: As soon as I put it in gear to move forward it... dies out - every time. It starts fine, and I can rev it up at full throttle making impressive noise and smoke, but when it's time to go it just dies out. It seems like some kind of adjustment, but what? I tried practically every single setting of the four lean/rich screws, no difference. I'm all out of ideas, have'nt a clue any more. The engine has a new CDI, a new stator, new sparks, new leads, new waterpump, new thermostats, carbs shiny clean and rebuilt with new kits, I mean... it should be running like new.

... It can't possibly be the regulator/rectifier... can it? Nah...

As the pros here say, they can and will run on two or three cylinders. Recheck your compression, and try a cylinder drop test. Start it, then pull one plug wire off and see if it changes sound of motor. Try each plug in turn. If it doesn't sound any different, that plug is not firing.
When you cleaned the carbs did you clear the high speed jets at the very bottom of the bowls?

If you keep winding it up in neutral you might soon be shopping for another motor.----Not a good thing to wind them up with no load and it proves nothing.

Thanx guys, Yes, cleared the high speed jets too, the carbs are all shiny and bling. Revving it up in neutral at least proves that the fuel flow is working nicely in the whole range. I'll try the droptest and see if they're all working.

Racer means that High revs can lead to a runaway motor when there is no load on it. It can throw rods out the side.

One other thing with the carbs: . If you have plastic bowls sometimes the bowls warp, letting air be pulled in at higher speeds. It won't be enough for gas to be leaking out, but that doesn't mean they are not warped.

You can check by putting a piece of sandpaper down on a piece of glass and sanding the bowls in a figure 8 pattern. If its not all sanding evenly then they are warped. If so, just continue sanding until they are even.

Winding it up in neutral proves nothing.----It will bark and roar , sound wonderful on 2 of 4 cylinders !

Thanks for the advice Riopga and racerone, much appreciated. I will recheck the evenness of the bowls (they are indeed plastic) and I definitely won't do anymore revving...
I have the feeling that at least one cylinder is indeed not working, as on the starboard side both cylinders get nice and hot, and the port side remains relatively cool. This definitely gives me new ideas to work with. I was too focussed on the carbs, but will focus on the ignition in the next steps and report back.

Right - I have an ignition problem, both port cylinders are not working, not getting a spark. I changed sparkplugs and leads and also changed the coils around from port to starboard and vice versa, but the the problem remains the same: the engine works on the two starboard cylinders, and the port cylinders are dead. the carbs are most probably fine and where so all along... The good thing is that at least the carbs are fully serviced and like new, won't be having trouble with those for a while. I am starting a new ingnition thread, hope to get your feedback there too guys. Thanx so far!