2000 Johnson 150hp Faststrike J150MXS1G - Stalls after running

[winfieldh]

Hello,

First time on lake with above motor. Started/idled brilliantly. Ran 1 mile at 2000rpm, then 2 mile at 4000rpm. There was a slight loss of rpm and recovery during the 2mi run. Shutdown to swim/fish for an hour. Started/idled fine. Pushed throttle ahead, at 1500rpm engine died. Started/idled again, could rev up in neutral over 1500 without problem, put in gear, slowly increased rpm, died again around 1500. Started/idled around for 10 minutes, throttled up, all good. Ran for 10 min, shutdown for an hour, same thing, would die around 1500rpm. Started/idled, got rpm upto 1300ish, pushed in electric choke and it popped up to 3500 rpm and kept going. Ran about 6 miles at 3500, slowly lost rpm and died. Started/idled fine, tried choke didn't do anything at first then did and would run fine. Stopped again, same again. The choke seemed to help, but not consistently.

Motor is new to me, mechanic purchased from rebuilt carbs 3 weeks ago, disconnected vro (yes, running 50:1). Runs fine on hose.

Fuel bulb squishy with fuel, not solid, not empty during stalls.
Replaced fuel filter/water separator last week.
Idling at 750ish when warm, 1100 when cold.
Pulled out ignition switch to make sure all connection solid (no shorting of the choke)

Seems this may be fuel related, but where to look?

Thanks,
W

 

[winfieldh]

Re: 2000 Johnson 150hp Faststrike J150MXS1G - Stalls after running

Forgot to mention and probably relevant, trying to throttle up and hitting 1500, engine would start to lose rpm's I could pull back throttle and keep it running. So above where I said it would die, that's not quite true. If I kept throttle advanced it would die, but pullback when rpm's started to decrease and it would stay running.

Thanks again for any insight...W

 

[boobie]

Re: 2000 Johnson 150hp Faststrike J150MXS1G - Stalls after running

When you push in the choke your bypassing the carbs and may need carb work. You said "first time on the lake", is this mtr new to you ??

 

[winfieldh]

Re: 2000 Johnson 150hp Faststrike J150MXS1G - Stalls after running

When you push in the choke your bypassing the carbs and may need carb work. You said "first time on the lake", is this mtr new to you ??

Yes, motor is new to me. Purchased from outboard mech that I have not ever dealt with before, but has been in business 30 some years. I will be contacting him tomorrow, but am trying to get a handle on what may be the cause.

By bypassing the carbs, I'm guessing there is too much air, not enough fuel, so throw more fuel at it and that is why it lights up with choke. Then the question is why will it rev up above the 1500rpm mark with no hesitate when in neutral, but in gear looses rpms at 1500? Presumably needs more fuel under load, so choking puts more fuel to it, enough to get it drawing more from carb bowls? I'm confused (not hard to do)....Thanks.

 

[boobie]

Re: 2000 Johnson 150hp Faststrike J150MXS1G - Stalls after running

When under load it needs more fuel to get power. Think about it. On your mtr it doesn't draw more fuel from the carbs, it by-passes them.

 

[winfieldh]

Re: 2000 Johnson 150hp Faststrike J150MXS1G - Stalls after running

Hi there,

Thought I would follow up on this after several weekends of trial and error and now seemingly victory.

New powerpack kit, plugs, wires, optical sensor did not help.
New fuel lines, primer bulb did not help.

New (used, but none to work) fuel pump and vapor separator float adjustment seemed to have done the trick. The mech I got this from replaced the fp with one from a motor that was known to have been working. He said he also adjusted the float in the vapor separator at the same time.

Cheers for now.
W