Honda 90 Oil pressure alarms

[mikewasem]

I have a '98 Honda 90 HP fourstroke. I had problems over about 2000 RPM with the engine slowing down, the alarm buzzer sounding but no indication of either high water temperature or low oil pressure. My mechanic replaced the thermostat and found a problem with the alarm circuit causing the buzzed and engine slowdown and replace the indicator module. Now, if I run over about 4500 RPM for 5 minutes, I get an indication of low oil pressure and the buzzer goes off and the motor slows. usually at higher RPM, oil pressure rises, so I don't know what's going on. I can run all day to 4000 RPM and it runs fine. Any suggestions?

 

[hondadude]

The only way to know for sure is to check the actual oil pressure as you are running at the higher speed.

Did the mechanic remove your oil pressure switch and clean it and the opening that it is in?

Although I do not recommend that you do this for a long time (not knowing what the real oil pressure is).....once you are able to make the motor go into guardian mode, slow the engine down to idle in neutral and remove the yellow wire going to the oil switch and see if the alarm goes off again. If it does, then there is something else causing the problem other than oil pressure. like faulty wiring or faulty ECM. i think the yellow wire screws onto the switch...so you should be able to go to the crossconnect (under the cover at the ECM) and pull the bullet connectors apart on the yellow lead...should be near the top of all the wires going through the crossconnect.

Mike

If it does not sound the alarm, then you are back to ....

1. Oil pressure is actually low.
2. The oil pressure switch is bad....or
3. The oil pressure switch is dirty or hole that it is in is plugged up with goo.

By the way...yes oil pressure normally rises the faster you go, but if you have a blockage in the system (junk in the pickup screen, etc), the oil pump will not be able to pump enough oil from the oil pan to allow that pressure to rise.