1993 johnson 150 won't run above 2500 rpm.

[martyman03]

I have a 1993 johnson 150hp 60deg motor. model vj150elatg. my problem is this. About 1 month ago i started having hesitation problems. they would clear themselves up and the boat would be fine for the remainder of the day. just recently i launched and i put it in forward thrust and the motor would not go above 2500 rpm under load. i took it out of gear and just reved the motor. it revs up just fine. i found the maint valve cracked on the primer solenoid, i r/r'd it it worked fine for a day. the next time i took the boat out it cracked again. i replaced it again. it worked fine for about 2 hrs and then the problem reappeared. but the valve was not cracked. i have changed my spark plugs, cleaned my fuel filter, changed my primer bulb, checked spark at all 6 cylinders made sure my fuel line was clean and unobstructed, from the tank to the fuel filter. no problems there. i have done a check on my overheat switches they are fine. the only thing i have found was that my pulse limiter was stuck open, no ck valve action to it. i replaced it. i checked my compression at all 6 cyls they seem fine. no readings just a quick blow ck, Here is more info. took the boat out today. ran rough for about 5 mins then ran fine, ran rough then fine. put boat on trailer. started pulling plug wires while engine was running. found spark down the left side but nothing down the right. Swapped plug top plug wires no joy. With top plug wires swapped started fooling around with the other plug wires. started pulling off the right side again and all of a sudden i have spark again. What would cause the 3 cylinders on the right hand side to have intermittant spark. Took boat out again for alittle more trouble shooting... put boat in water, it sputtered at first shut engine off, fired engine up it ran fine for about 5mins then at wot a horn sounded steady until i reduced throttle to mid range. i ran engine like this for about 5 more mins then went back to wot. engine ran fine for about 35mins til i started running out of gas. Does anyone have any ideas as to what would be making this boat hesitate like this at different times? Sometimes it happens right off the trailer and others are out on the lake just cruising around. any help would be appreciated. Marty

 

[seahorse5]

Re: 1993 johnson 150 won't run above 2500 rpm.

The starboard bank ignition is controlled by the powerpak, the stator, and the shift assist switch. My guess is the switch is sticking or shorted. Remove the black/yellow wire from it and see if you get steady spark now. If not, it's time for a QUALIFIED professional or being knowlegable and having the required test equipment and service manual.<br /><br />By the way, a pulse limiter passes air both ways, it is not a check valve. Internally, there is a leaf spring that "pops" shut if there is a backfire in the crankcase, and that protects the VRO (OMS) pump.

 

[martyman03]

Re: 1993 johnson 150 won't run above 2500 rpm.

Which black and yellow wire, there are two of them coming off the shift switch. there is only one power pack on this motor. with what appears to be 3 separte coils. will the power pack go intermittant? or will it just go out completely?thanks for the help so far. i am just using the clymer book that is out for this motor.

 

[angus63]

Re: 1993 johnson 150 won't run above 2500 rpm.

i have '95 175hp evinrude with one powerpack. I too lost even number cyls. It is possible to loose only 1/2 cyls with one pack. I replaced the powerpack & sensor and all is well. P.S. Just disconnect the shift switch at the control and see if the problem goes away to eliminate that possibility. Good luck........

 

[martyman03]

Re: 1993 johnson 150 won't run above 2500 rpm.

Which sensor are you talking about? the shift interrupt switch?