1988 Johnson VRO "SLOW"

[rwhit11]

have a 1988 150 VRO "J150STLCCA" I have been having some overheating problems and this has created a question. Does my motor have the "SLOW" on it. I have had several cases where I would be going along and then the motor would drop to about 2500 RPM. I would shut sown, wait a bit then crank back up and go. I have also gotten the alarm from the motor a couple of time. I did overheat so bad that I lost two pistons and have just done a rebuild but the first time out it did the drop to 2500 RPM again.

 

[Bosunsmate]

Not sure if you have slow, but whats the alarm, continuous? beeping?
Have you chosen to keep the VRO?
Why did it overheat?

 

[emdsapmgr]

Your model number indicates it is a 1988 model. That engine was the last year for the twin power packs. In 1988 only the big block 90 degree V6 engines had the SLOW feature 200, 225's. In 1989, it was extended down the the XP/GT models when OMC went to the single power packs. Unless you have a 1989 ignition system on that engine there is no ignition reason for the rpm's to drop to 2500. Any chance you are losing spark to on cyl when the engine warms up to normal operating temps? You did not mention what horn you are getting. Is it constant or intermittent? A constant horn can be from one of two sources: an overheat, or from a high rpm fuel restriction. (That engine does have a fuel vacuum switch which monitors fuel flow pressure.) During your overhaul of the engine did you discover and resolve the original overheating issue? (New thermostats, check under the head covers for debris, new impeller, replaced the rubber water diverters in the block?)

 

[rwhit11]

You are correct, mine does have the two power packs. The alarm is a constant from the motor, when I overheated and fried the pistons it was coming from the remote box. I have a call into the mechanic that did the rebuild to verify that he did put in two new thermostats, I am rebuilding the water pump but the one I took out looks good so I don't know if that will make any difference.

We felt that the VRO had failed and that was what caused the big problem. It looks like I had used very little oil. I have disconnected the VRO and plugged up the hole in the carburetor. I drained the fuel tank ( all 21 gallons of it) pumped the lines out and refilled using a 50 to 1 mixture. Is their an alarm that I need to disable and could that be what I am hearing? When I say I am overheating I am going by the alarm and not from measuring the temp. Can I actually put a temperature gauge on this engine.

I have a hand held infrared thermometer and I am going to test it this week end on the muffs and see what I get on each bank. I will post my findings.

 

[rwhit11]

Where is the horn located on this engine. A friend told me that the only warning horn was located in the remote and it was very loud. The noise I am hearing sounds like it is coming from the motor and is not very loud. Could I be hearing something else on my boat?

 

[Ibl0wstuffup]

The warning horn should be on the remote or on the tach if it has system check. I don't know if system check was available in 88.

 

[Bosunsmate]

Where is the horn located on this engine. A friend told me that the only warning horn was located in the remote and it was very loud. The noise I am hearing sounds like it is coming from the motor and is not very loud. Could I be hearing something else on my boat?

yes, a mechanical problem
the remote is where the buzzer is, if you are a bit hard of hearing or its windy i suppose you might not here it in the control box.
continuous means overheat. You should run it at home in a barrel just at idle for a while and feel the heads, they shouldnt get so hot that you cant keep your hands on them for at least a few seconds.