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What came first...SLOW Mode or no water pressure?

2

238 Coastal

New member
95 200hp Johnson Ocean Runner 950hrs -
Well cared for motor was running great till this weekend when it went into SLOW mode. Yes, it is SLOW mode, idles but shakes in gear and low rpm's AND starboard side bank not firing. Was not hammering it all, very easy day of morning trolling and then drift fishing inside. NO alarms. NO nothing, other than water pressure gauge pinned to 0 but still steady stream from tell tale. NO over heat, block as cool as a cucumber and days later still in SLOW mode. I have checked shift interrupter switch, it is still reducing rpm's even in SLOW mode. I have checked temp senors at least for continuity, both good, but worried now because port side temp switch is NO LONGER AVAILABLE. VRO was replaced in July. Impeller replaced in July. Carb's rebuilt in July. Oil level was 2/3 full on a 3 gallon tank.
However, I did find vacuum switch plug not to be in great shape, it is the one that is encased in rubber for some reason. But there were no performance issues from that before, and to be honest, me digging around in there AFTER may have damaged that plug.
So...does SLOW mode cause the lack of water pressure? Or did the water pressure drop cause the SLOW mode?
I can't find anywhere where the vacuum switch would cause this...
Again, I had the Johnson in prime running form at both WOT and idle/trolling (salmon) and ALWAYS running very cool. NO ALARM, though alarm does sound at start up...
Thanks for any and all help!
238Coastal
 
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SLOW is activated at 2800rpm. Above 2800 shake,will not run any faster. Runs good below 2800. Is this what your motor is doing?
 
SLOW does not cause no water pressure.fuel restriction will not activate SLOW. Do know how to check your warning system?
 
Rwbutler said:
SLOW is activated at 2800rpm. Above 2800 shake,will not run any faster. Runs good below 2800. Is this what your motor is doing?
Click to expand...
Yes, motor is definitely only firing on port bank, pulled plugs and wires to verify. Shift interrupt switch activated via screw driver still delivers reduced rpm's at idle.
Thanks!
 
Thank you. And yes, I did NOT know there was a way to check warning system other than at start up, or grounding out temp switches... I hear the warning at ignition start up, but have never heard it after that.
Only have read that over heat and low oil will activate SLOW.
I have OMC owners manual explaining alarms, but not testing...
 
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238 Coastal said:
Yes, motor is definitely only firing on port bank, pulled plugs and wires to verify. Shift interrupt switch activated via screw driver still delivers reduced rpm's at idle.
Thanks!
Click to expand...
Let me put it another way. sLOW only happens above 2800rpm. If you have no spark on one bank,you need to trouble shoot your ignition system.I wou!d start with stated chscks.
 
Rwbutler said:
I'm sorry, "stated" should be stator.
Click to expand...
Thanks for that, I don't have receipts for the stator being swapped out anytime...always "looked" new to me.
When you say test, are you referring to just the ohm's test or is there more to it?
Thanks again.
I have since tested both temp switches and alarm system, and are operating in spec. But have never heard an alarm go off for what is happening...
Still no water pressure, but am going to replace both thermo's as soon as I can find all parts.
 
Their is no alarm for "no spark on port bank". Home test,shorts to ground,voltagetest. One problem at a time.Let's get you motor running on all six cylinders. Suggest you refer to C.D.I troubleshooting guide located on this site.then we can fix your w/pressure gUge.
 
Rwbutler said:
Their is no alarm for "no spark on port bank". Home test,shorts to ground,voltagetest. One problem at a time.Let's get you motor running on all six cylinders. Suggest you refer to C.D.I troubleshooting guide located on this site.then we can fix your w/pressure gUge.
Click to expand...
Will do, thanks for the info, was not aware of trouble shooting guide on here!
On West Coast, will hopefully have some more info tomorrow morning.
Thanks again-
 
Rwbutler said:
Their is no alarm for "no spark on port bank". Home test,shorts to ground,voltagetest. One problem at a time.Let's get you motor running on all six cylinders. Suggest you refer to C.D.I troubleshooting guide located on this site.then we can fix your w/pressure gUge.
Click to expand...

So finished testing...Found loose part on stator as the culprit! Runs well with jury rig fix, NOT taking it out like that though, new stator due this Tues-Wed. Will take it down to harbor for load test etc. soon after. Hopefully find out about water pressure (gauge) at that time. Any chance they are related at all?
Thanks again for steering me back to "basic" trouble shooting.
 
Remove hose from back of w/p gauge,remove other end of that hose at motor. Get one of those can of air (for cleaning key board) spray into gauge.Does gauge work? Spray into hose,does air come out other end?start motor,does water come out where hose was removed?
 
Rwbutler said:
Remove hose from back of w/p gauge,remove other end of that hose at motor. Get one of those can of air (for cleaning key board) spray into gauge.Does gauge work? Spray into hose,does air come out other end?start motor,does water come out where hose was removed?
Click to expand...
Will give it a shot, thanks!
 
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