Fast Strike 150 Will Not Rev Over 2500 (possible SLOW mode)

[we-a-float]

Hey guys,

Have a 1993 Johnson Fast Strike 150 that will not Rev over 2500. I assume it is in SLOW mode from the research I have done. The motor idles ok, revs from a idle, but will not run over 2500. The stator, powerpack, pickup sensor, wires, plugs have been replaced. The compression varied about 10 psi between cylinders. Compression around 105 psi. Have spark from all 6 coils. I have disconnected the Diode, both temp sensors, lower plug from VRO to oil tank, all with same results. Pre-Mixing gas/oil. Carbs are clean, fuel pressure good.

Given the fact that the rpm is limited to 2500 and does not really vary from that, has me to lean towards a electrical ignition problem.

The Boat has been to two different dealer service shops the first could not seem to find the problem. The second stated that the PowerHead is causing the problem, due to compression, and needs to be replaced. I don't really buy that.

Wanting to get your feedback.

Thanks...

 

[jakedaawg]

Are you getting a warning horn or a light on sys check guage if equipped?

 

[boobie]

Do a cylinder drop test on it to see if it's running on all cylinders.

 

[jakedaawg]

When the rpm is limited is it a smooth running 2500 or rough and jerky?

Slow, is activated by no oil sensor, over heat sensor, fuel restriction sensor, bad pack/s, cant remember if there was

 

[bob johnson]

if you turn the motor off for a short period of time and remove the key...you reset SLOW mode ( as long as the temps drop below a certain level...I forget what it is...probably about 180 or so).... then when you restart, before the motor warms up...... you should be able to go full throttle......if you cant...its NOT SLOW mode that is your problem..its something else........ SLOW engages when the temps go over 240 degrees!!!!!!!!!!!


bob

 

[we-a-float]

Thanks for the replies.

Jake - I do get a horn when the harness plug to the oil injection tank is connected. The harness to the oil reservor has been disconnected due to pre-mixing the fuel.

Boobie - Yes, I have tried a drop test. All cylinders seem to be firing. I do get a variance in RPM and idle with each cylinder dropped.

Jake - Yes, when the 2500 is reached it is a rough idle such as a rev limiter or miss.

Bob - The condition does not reset. From first start it water, will not rev over 2500. Run for a while, let cool down, restart I get the same condition. Will idle and run up to 2500 but will not go over that. The boat will never plane. I had also read that slow could be enabled if there was a grounded sensor wire or condition in the harness. Is this true?

What should the acceptable compression be for this motor given the age? How many revolutions should the motor spin to get an accurate compression test.

 

[bob johnson]

Thanks for the replies.

Jake - I do get a horn when the harness plug to the oil injection tank is connected. The harness to the oil reservor has been disconnected due to pre-mixing the fuel.

Boobie - Yes, I have tried a drop test. All cylinders seem to be firing. I do get a variance in RPM and idle with each cylinder dropped.

Jake - Yes, when the 2500 is reached it is a rough idle such as a rev limiter or miss.

Bob - The condition does not reset. From first start it water, will not rev over 2500. Run for a while, let cool down, restart I get the same condition. Will idle and run up to 2500 but will not go over that. The boat will never plane. I had also read that slow could be enabled if there was a grounded sensor wire or condition in the harness. Is this true?

What should the acceptable compression be for this motor given the age? How many revolutions should the motor spin to get an accurate compression test.

sooo its NOT a S L O W mode issue.........ill subordinate to the electrical guys....could be a fuel restriction...... but I think there is an alarm for that.....

 

[jakedaawg]

Still could be in slow or safe or whatever they called it that year.

Cdi electronics. Com has a good troubleshooting shooting guide. Easier than me typing it out. Basically, you need to bypass the various alarms that put it in safe mode....temp, oil, and fuel restriction(maybe, cant remember on this one).

Either there or a manual. Usually not a big deal.

 

[flyingscott]

edit

 

[flyingscott]

Have you checked the temp sensor? Or have you verified the temp it is actually running at? Sounds like it is in slow mode.

 

[bob johnson]

it cant be the temps...he says it happens right away...he starts a COLD motor and he can not get past 2500 ...... there is no way the temps can get to 240 degree in 30 seconds!!!!!!!....he says he starts and trys to get up on plane and it wont go past 2500...... and THEORETICALLY SLOW mode is reset when the key is turned off...... and the motor has cooled.......

 

[flyingscott]

it cant be the temps...he says it happens right away...he starts a COLD motor and he can not get past 2500 ...... there is no way the temps can get to 240 degree in 30 seconds!!!!!!!....he says he starts and trys to get up on plane and it wont go past 2500...... and THEORETICALLY SLOW mode is reset when the key is turned off...... and the motor has cooled.......

Not if the temp sensor is bad or shorted. The problem does not happen right away he has to get to 2500 rpm and it runs fine up to that. You could also have a bad powerpak or a disconnected or shorted wire. Why were all those parts replaced? was this a problem you were chasing before all those parts were replaced ?

 

[bob johnson]

Not if the temp sensor is bad or shorted. The problem does not happen right away he has to get to 2500 rpm and it runs fine up to that. You could also have a bad powerpak or a disconnected or shorted wire. Why were all those parts replaced? was this a problem you were chasing before all those parts were replaced ?

well, that's what Im saying....the MOTOR is PROBABLY NOT OVERHEATING.....so its not an hot motor issue...its most likely electrical....but I wouldn't rule out an electrical-fuel combo.......not sure how the fuel restriction alarm works.......it could be something is shorting out..... I had an electrical spark jump and it resulted in limiting the rpm...just like the OPs motor

 

[flyingscott]

Well good luck with your motor looks like Bob has all your answers so I will defer to him.

 

[bob johnson]

Well good luck with your motor looks like Bob has all your answers so I will defer to him.

classic

 

[we-a-float]

Thanks for the replies.

Flyingscott - Yes the parts were replaced chasing the problem. Started with the power pack, plug wires, plugs, pickup. It was from CDI. From the initial tests it seemed like that might have been the culprit.

Does anyone have a wiring schematic for this engine? Is there one or more control wire that goes to the power pack that sets the SLOW mode or rev limit?
I thought the wire or wires could be disconnected from the pack harness to eliminate the possibility of the SLOW condition, to rule it out.

Thanks again.

 

[Chris1956]

On my '98 Johnny 150, there are individual wires to kill 1/2 the motor spark. They are black/orange and black/yellow. The shift interrupt switch grounds one of them, as does the overheat sensor. The ignition switch grounds both of them, killing the spark to all cylinders.

I would disconnect the shift interrupt switch and see if that helps.

You should get a wiring diaghram, as there are a couple of diodes that need to be working properly for the motor to function properly.

 

[jakedaawg]

Is it losing spark to just one bank or some on both?

I use a spark checker that tests all six at once. I realize most don't have that ability but....

I cant even remember if that's a one pack or two pack motor. It April and I haven't lifted.a hood in a bit...

I still think you should try cdi trouble shooting guide.

Just cause it's not overheating doesn't mean it's not in slow. The sending unit can be bad. Easy to check. Disconnect tan wire at sensors and check to see if you have continuity between block and sensor side of lead. Two sensors, one on each head

Same thing with fuel restriction switch.

Oil system is a little trickier but you need to make sure the vro itself is unplugged and running mixed fuel. Not just the sending unit from the tank.

 

[jakedaawg]

I just reread everything. Have you checked/replaced the optical?

It's possible you got a bad pack new. It happens more than they admit, part of the reason I think that cdi has such good warranties and trouble shooting resources, call them.

 

[we-a-float]

Chris - Thanks for the reply. Yes, I will try to get a diagram. So, given the wire color combo and wiring is the same on my motor, removing the black/orange and black/yellow from the pack harness should not allow the pack to engage the SLOW mode, if that is the trouble. Anyone know if this is correct?
Thanks for the note.


Jake - Not sure if loosing spark to which bank or both. Checking spark per cylinder out of the water is all I have done. There is spark at each cylinder in that respect. The motor has three coil packs.I will work through the trouble shooting guide.

Do you know where the fuel restriction switch is located, by chance? Thanks for the info.

Yes the optical came as a package with the power pack and wires. So yes the optical has been replaced as well. I had wondered if the pack could have been a defective unit from CDI, but figured they tested there units before shipping out from manufacture. Also the guys that had the boat at the last dealer shop did not say anything about a defective pack. Surely they would have checked that...


Anyone have a reference or manual that shows the compression specs? What would be acceptable range and variance ?


Thanks Again ..