RTU low oil pressure

[Tyler J]

Last winter I overhauled my 39 RTU. It has all new main and rod bearings. The engine was completely disassembled and washed in a steam cabinet, and all parts were thoroughly cleaned before reassembly. After putting it together, it had about 25 lbs of oil pressure. It worked great all year.

When I took it out of the shed this spring, the oil pressure jumped to 25 lbs, but dropped back to about 5 lbs right away.

Does anyone have any ideas as to whats going on here? Any suggestions on how to fix it?

Any help would be great.

 

[J.Wondergem]

Check the relief valve, and see if you have a booger caught in it.

 

[J Wuertz]

Did you put dertegent oil in the crankcase? This happened to me when I put some 10W30 in the engine. The engine ran fine for a while and then the oil pressure dropped. I drained the oil and it was was looking pretty bad. I refilled with straight 30 and changed the filter and it is working good now.

 

[Tyler J]

I got problem fixed. It was the oil. I guess I put 10W 30 in when I put the motor together. I pulled the crankcase cover, pulled out the oil pick up screen and noticed a thin clear latex-like film covering the screen. It must be from the detergent oil. I cleaned the screen, put straight 30 weight in and have great pressure.

Thanks for your help