Johnson 140 losing power and almost dying

[Dan757]

Good afternoon all,
My father in law and I recently replaced a piston, rings, all seals, and all hoses on my 1990 Johnson 140. We took it out to run it through the break in procedures and for the first hour staying below 3500 RPM she did well. Then in 2nd hour when we tried to take it up some she would die down slowley. This was not constant either some time we could make 3 trips across the creek and not happen once and sometime she would do it 3 times in one trip. If you throttle back once she starts to die and try again she will fire right back up. If you throttle foward when she starts to die it changes nothing. Any thoughts?

Thanks,
Dan

 

[Dan757]

Re: Johnson 140 losing power and almost dying

Any ideas?

 

[boobie]

Re: Johnson 140 losing power and almost dying

Did you do the carbs when you had it apart ??

 

[Dan757]

Re: Johnson 140 losing power and almost dying

Thanks Boobie,
No I haven't because I knew the person I bought it from and I knew the mechanic who had done work on the boat both from my last unit. I was told by the mechanic that they were done last year...that being said I am going to go ahead and do them now. Another mechanic at work told me based on the symptoms that he can almost guarantee I have some junk in a high speed jet. Last night I was checking all the hoses to ensure I was not getting air in and found that 2 of the choke/primer hoses had split so I cut them shorter heated them up and slipped them back on to the tees. The line from the fuel pump to the carbs was partially kinked. It was longer than it needed to be since I removed the VRO and went premix; the new nipple is in a different position than where it was on the VRO. I have a theory that the kink may have been a big part of the problem. Here goes...the boat ran fine on lower RPMs because less fuel demand...when I try to throttle up she drained the fuel in the bowls and when I come down and come back up it gives the bowls time to refill.


Thanks,
Dan

 

[boobie]

Re: Johnson 140 losing power and almost dying

Good theory, Try it and see what happens.

 

[Dan757]

Re: Johnson 140 losing power and almost dying

Good theory, Try it and see what happens.

Ok guys I replaced the spark plugs, cleaned out the carbs and replaced some of the clamps in addition to fixing the kinked hose. We also moved the primer bulb down flow of the fuel water separator...Well she screamed up and down the river! Running great! Thanks for the help!

Dan

 

[Joe Reeves]

Re: Johnson 140 losing power and almost dying

Glad you cleaned those carburetors... probably what blew the engine the first time (carbs running lean!).