oil pressure safety switch

[JimHo]

A friend and I brought my boat home last weekend, and we had a bit of trouble with the A4. In typical fashion, I managed to break the tiller and stall the engine within 30 seconds of letting go of the pennant in a busy mooring field... Gorilla tape and roller-furling saved the day.

We bypassed the oil pressure safety switch with a cotter pin, and were able to get her back running fine. I kept a wary eye on the oil pressure gauge, and we maintained about 38 lbs.

I pulled the switch last night and checked it with a test light and compressed air. I had an alligator clip wire to a positive post on a battery and to one post on the switch. I had the test light to the negative post and the other post on the switch. I had about 10 lbs of pressure on the compressor and had the air nozzle taped to the switch. It seemed to be working fine.

When I removed the switch, I expected some oil to come out of the fitting, but it was clean. The sensor cavity was clean as well. Does that indicate that there was something clogging the 90 degree fitting?

By the way, the oil is to the full level on the dipstick.

Thanks - Jim

[Administrator]

Last edited by JimHo; Today at 08:50 AM. Reason: post didn't like acronym OPSS

Jim:

The OPSS acronym should be recognized by the software. You won't see any indication of that when entering the post, but it should be evident once your message has been posted.

Bill

[Al Schober]

Jim,
If you're not getting oil to the switch, it isn't going to work. Definitely check any fittings ahead of the switch. Unscrew them from the block and bump the starter - you should get oil coming out. BTW, there are two oil fittings on the valve side of the block. One is right behind the flywheel. The second is just forward of the transmission by the oil pressure adjuster.

[JimHo]

Just so I am prepared - how much oil should come out?

[joe_db]

Eventually all of it!
You could screw a pressure gauge in there to see what happens without dumping oil all over.

[JimHo]

I'll do that - sounds like the right way to go!

[JOHN COOKSON]

If you can demonstrate that you are getting oil under pressure to the OPSS you could reinstall the OPSS and see what happens. If it fails again scrap it because it has an intermittent problem. Alternately you could just buy a new one now once you are sure you are getting oil pressure to the OPSS.
If you want to go through the whole drill reinstall the OPSS but don't put the wires to it. Instead connect the two wires to the OPSS together. I use a small tang of metal that I can push the connectors on to then wrap the connection with tape. Then start the engine with the OPSS bypassed and lay an ohm meter on the OPSS contacts to see if it is closing or not.

TRUE GRIT

[BunnyPlanet169]

Just so I am prepared - how much oil should come out?

With the engine off, just a dribble from oil in the gallery. With the engine running, it's pumping till empty.... The switch should generally be a little wet with oil, as you've guessed already.