SLOW system trouble on 1996 115hp ocean pro

"Motor ran great first day out

"Motor ran great first day out aprox. 3 hours. The next week after 4 miles of running SLOW sytem kicked in lowering rpm to 2500. We are not running a VRO oil system, we mix our own fuel /oil. So the VRO plug is not connected.We checked the Diode on tan wires to sensors, we checked the temp. sensors. We put another power pack and coils on, it ran good for 100 yards and then slow kicked in again. There are no audible alarms sounding. We grounded the tan temp sensor wire to check and the alarm worked. What should we check next??? WE are at a remote location ,San Clemente Island ,any help appreciated, Bob Hill"

1: What plugs are You using?

1: What plugs are You using?
2: If You have a system check instrument/rev counter try to disconnect it.

"1: New set of Champion QL78YC

"1: New set of Champion QL78YC
2: Don't have the system check instrument, because we used an older wire harness that was in place. We purchased the Johnson adapter harness, to go from the previous round cannon plug to the newer square plugs.Everything worked and buttoned up nicely, for the first day.
3: the Diode Check what kind of reading should we be getting? the book said none in one direction and" strong" in the other. Strong? is a 50% signal or half the total signal on an amp meter satisfactory? compared relatively to touching the two probes together?
4: we have two of these motors with low hours that were fogged and stored since 2002. We have been using the one for parts, been thinking about yankin the diode off the spare tommorrow.

Thanks, for the quick response, we hope to enjoy some of our weekend on the water, What next???
Robert Hill, San Clemente Island Fire Dept. Station #11 water rescue"

"The diode in the harness is o

"The diode in the harness is only to prevent the SLOW to engage on a low oil alarm from the oil tank. If You have a 'spare' engine, try to swap the power packs."

"There is another possibility

"There is another possibility and that is the alarm horn. If it is of the 'old' type without a separate ground wire it may cause what you are experiencing. If You know the cooling is ok, try to disconnect the horn (remember to isolate the wires). This problem often happends if voltage exceeds 14 Volts in the charge system."

"We swaped the powerpack today

"We swaped the powerpack today It ran 100 yards then Slow problem again with the new pack and coils.
Thanks for the diode info, the book said if the diode was bad that the SLOW system would kick in with no alarm.Thats what we are expierencing.
Our cooling is fine, we also run an after market head temp. gauge so the alarm is not needed. Tommorrow we will disconnect the horn and isolate the wires.
Thanks, If your ever out our way your invited for a tour of the island and dinner at the Fire Station. Robert Hill"

"You mght also try to disconne

"You mght also try to disconnect one temp sensor at a time then run the motor, just to eliminate the possibility of a bad sensor. If you are running a temp gauge then you are most likely getting the temperature from only one head. I prefer a water pressure gauge and an alarm system."

"Thanks papasmurftd, Ive tried

"Thanks papasmurftd, Ive tried the temp sensor disconnect. I also run a pressure gauge, and if I have to get rid of the alarm I will put a head temp sensor gauge on the other head and run two gauges."

"Mr.Ringvold, Today I disconne

"Mr.Ringvold, Today I disconnected the horn, it had one connector with two purple wires and a connector with a black wire, and a tan wire connectort. The boat lost all power,would not turn over, so I replaced the purple and black connections and left the TAN disconnected and she ran.
I also disconnected the sendind units tan wires located near the heads.
We launched the boat it ran for 200 yards and then SLOW kicked in again.
Any help appreciated,, Robert Hill"

"I just swapped out the rectif

"I just swapped out the rectifier, ran great for 5 minutes then started missing real bad at mid range and above rpm.
The sledge Hammer is my next tool of choice!!!
R.G. Hill"

Disvonnect the brown wire from

Disvonnect the brown wire from the plug at the power pack! If SLOW kicks in then the Power Pack is defective!

"Hi Robert,
I just bought the

"Hi Robert,
I just bought the same motor you have used. I'm eager to get it bolted on my transom and give it a try.
- Did you resolve your issue?
- How do you like the motor, other then the problems your are having?
- I'm also using my old controls with the adapter cable, in your opinion should I go with the System Check option.
- I had a really loud 1987 90hp v4, how is the sound level on your motor?
- How did you disconnect your VRO? Just plug the line and unplug the cable?

Thanks,
Jim Arndt"

"I was informed that all my S.

"I was informed that all my S.L.O.W. issues are the result of disconnecting my V.R.O. so I have reinstalled the system and I will test it this weekend. The Sound level is very low. I don't think the system check is anything but idiot lights and I would rather have gauges, but what do i know my boat ain't runnin,,,"

"SLOW kicking in has nothing t

"SLOW kicking in has nothing to do with disconnecting the VRO providing the cable from the VRO is disconnected. If You have a very low alarm sound when it happends it indicates a 'creeping' amperage going through the horn. If slow kicks in that is caused by either a leaking temp sensor or a short somewhere in the engine wireing harness/connector, (VRO disconnected, oil tank wires disconnected) or a 'leaking' horn."

"Connected the VRO back up and

"Connected the VRO back up and put 20 miles on engine this morning, ran perfect.
The VRO cable was disconnected when we had the slow problem
I was told that you had a change in the VRO's in the early 1990's and you could no longer run with them disconnected.The books do no reflect this though.
My motor is running purfect and I'll leave the VRO connected on all my post 1990 motors in the future,"

"What You may referr to as a &

"What You may referr to as a 'change' in the VRO system was that they added a 4th cable to battery+. The 'explanation' given was to give a more stable current and amp to the electronics in the VRO alarm unit. Internally in the alarm unit a Zener diode was added working as a relay. When ignition 'on' (purple) wire the diode opends for the 'red' cable which is used as power supply for the unit. Without this function the unit would draw power even when ignition was off. There were other 'small' changes in bits and pieces as well, but non major. The reason for the problem was that the VRO in some cases triggered alarm and slow due to electronic reasons rather than oil failure. Pulling the blug from the VRO was sometimes the 'only' solution to get rid of the problem and even in the newer versions with 4 cables, pulling the plug the VRO can not give alarm!!!!!!!!
In the cable harness on the engine there is a blocking diode. On the power pack side there are the VRO sensor, temp sensors and on some engines vacum sensor. On the instrument side is the oil level sensor from the oil tank. This to prevent SLOW to kick in at low oil alarm or short circuit/malfunction of the horn or the harness. However no diode totally blocking. With charging currents climbing above 15 Volts and use of 'gel' batteries problems may occur. Even some power packs have been too sensitive and kicked in slow, but not enough amps to trigger the horn.
I could go on, but it will take too much both space and time, but what may have happened in Your case is that the VRO alarm unit with its 4th cable has managed to 'compensate' for a ground leakage somewhere in Your cabling system and the leakage through the harness diode by keeping the voltage in Your alarm cable. I am afraid that reconnecting the VRO only temprorarly has 'solved' the problem. I suggest taht You do a test of the harness diode, not by an ohm meter, but connect 12Volt battery on the power pack end and measure voltage at the pin in the harness connector. Any voltage: change the diode. Any voltage at the ground pin: short circuit between the alarm (brown) cable and ground. Remember to disconnect ALL grounding points to block, VRO, Powerpack, starter solenoid, oil tank etc before performing this test!"

"Thanks Morten, Put another 20

"Thanks Morten, Put another 20 miles on the Engine this evening, taking it out in the morning for a few hours. I have a digital voltage gauge on our new Lowrance and I did notice voltage going as high as 15.1 today. Thanks for all your help, I will perform the diode test this week, with 12volts.
Last week, I changed out the Power pack, the Engine wiring harness, the rectifier, the coils and the plug wires, none of this helped."