Failed Oil Pressure Adjustment

[Mark Millbauer]

Don and All,
Since I have had my A4, it has delivered 20 lbs oil pressure regardless of RPM's. Last weekend I warmed her up and successfully adjusted the oil pressure to average about 40lbs. Today--one week later and the next time it was fired up--it only produces 10-15 lbs regardless of rpm's. Tried cleaning the contacts on guage and sending unit with no difference. What happened? Did I adjust it too much and break the relief spring? This is the late model motor, should I order the new, old style adjustment kit? Should I take the adjustment assembly apart? BTW, this is in a C27 so it is very hard to get to the adjustment assembly. Thanks for your input.

Mark Millbauer
C27 "Solution"

[rigspelt]

I once thought I had an oil pressure problem on a power boat. Solved it by buying an in expensive mechanical oil pressure gauge and screwing it directly into the electrical oil pressure gauge sender's port. It read normal pressures. I replaced the old analogue gauge with a digital one that also read normal, and lived happily thereafter. I left the mechanical gauge beside the engine, but never needed it again for years.

[Mark Millbauer]

thanks for you reply. It's good advice. I plan to check it with a mechancial gauge when I can. However, it seems that there has been enough problems with the oil pressure adjustment hardware reported that I wonder if this has come up before and if Don and the others at MM might have some insight.

Mark Millbauer

[Don Moyer]

Mark,

I thought I had responded to you previously, but perhaps I forgot to press "send". In any case, my suggestion to you was to check the amount of thread you have remaining outside of the 3/4" locking nut. If you have approximately 1/2" of threaded shaft remaining, you can turn the adjustment in another turn or so and then start the engine and see what the pressure is when the engine is fully warmed up. The best time to check the oil pressure is after an hour or so of running the engine under load at your favorite cruising RPM.

The spring-and-ball type of regulating valve used on late model engines does have a bit of history of being "skittish" at times and the pressure will actually lower when you turn the threaded shaft in, if the ball repositions itself over the orifice in the block.

If you still have problems chasing your pressure after confirming the indications of your cockpit gauge with a manual pressure gauge as suggested by rigspelt, you may have to replace the spring and ball valve with one of the sliding valve type you see in our catalog.

Don

[sastanley]

Mark, if it makes you feel any better, I don't think I have ever seen my oil pressure gauge over 20 PSI...sometimes it is so low I don't know if it is registering!!!! It is a good thing I do not have any oil pressure cut-off switches.

I cleaned all the gunk off the left rear of the motor and found my adjustment bolt, and turned it 1/2 turn right at the end of the season. It did seem to bring it up enough to notice a change on the gauge, and have 15-18 PSI when motoring about 1600 RPM. so I am hopeful another 1/2 to 1 turn will get me consistently over 20 PSI next season.

[Mark Millbauer]

Don and all,
Great input. Thank you.
I didn't realize the procedure was to adjust the oil pressure with the engine off. I did it with the engine running after warinming it up. It adjusted to 40lb from 20 lb just fine while it was running in the slip. I shut it off and went home. The next time I fired it up a week later, it was only at about 10-12lb even after cruizing under powere for an hour. Again tried to adjust while out on the water. No change. After reading Don's post, I suspect that something happend to the ball and spring assy.

Mark