High Oil Pressure

[rgeddes]

I have a 1991 Four Winns with a OMC 4.3L Cobra Engine. When running the boat at 20mph, the tach is 3,300 rpms, and the oil pressure is 65-70. When I increase the speed the oil pressure goes up to just under 80. This seems high. I just changed the oil and filter with a marine filter. Is this oil pressure too high?

 

[Bondo]

Re: High Oil Pressure

Ayuh,... Is this after the motor is well warmed up,..??

 

[rgeddes]

Re: High Oil Pressure

Yes. After the boat warms up on the lake. If I remember right, the oil pressure was lower last year. I've read on other post about testing the oil pressure to see if the gage is wrong. What do I need to do this and How? Also, I've read posts about an oil pressure relief valve. I'm assuming this engine has one. Where is it located?

Recently, I changed the oil and filter. I used a Delco filter the first time (PF51) and thought this could cause the problem. I replaced it with a Sierra oil filter and it reduced the oil pressure a little. I am using 25/40 oil.

 

[HT32BSX115]

Re: High Oil Pressure

Howdy,

before you believe you have "high" oil pressure, put a direct reading gage on it and verify it...

Make sure the engine is fully warmed up......

 

[RogersJetboat454]

Re: High Oil Pressure

Yes. After the boat warms up on the lake. If I remember right, the oil pressure was lower last year. I've read on other post about testing the oil pressure to see if the gage is wrong. What do I need to do this and How? Also, I've read posts about an oil pressure relief valve. I'm assuming this engine has one. Where is it located?

Recently, I changed the oil and filter. I used a Delco filter the first time (PF51) and thought this could cause the problem. I replaced it with a Sierra oil filter and it reduced the oil pressure a little. I am using 25/40 oil.

You need to round up a mechanical oil pressure gauge, and take a direct reading from the engine. Find where your oil pressure sender threads into on the engine. Remove it, then thread the gauge into the port it was threaded into. Start the engine, and be sure to check it for leaks. Run the engine till it has fully warmed up and check your pressure.

The engines oil pressure relief valve is located in side the oil pump. Oil pump is mounted on the rear main bearing cap inside the oil pan. Not a quick easy job if you need to go there. I Hope your boats sending unit or gauge is wrong....

 

[Randy J]

Re: High Oil Pressure

i use castrol 10w-30 in my 4.3 never no problems owned boat 12 yrs now

 

[rgeddes]

Re: High Oil Pressure

Fixed it. I replace the Oil Pressure regulator and Oil Pressure switch. Both of these units are located on the top of the block near the Distributor. I had to remove the distributor cap to get to it. When I remove it, a small adapter snapped off in the block. I used a tool to back out the adapter. I installed a new adapter, oil pressure regulator, and oil switch. The oil pressure is back to normal. It took about 1/2 hour to complete the job(excluding back out the snapped off adapter) and around $60. The adapter was the most expensive part, $22.

This week, I plan to change the lower unit oil. I hope that goes smoother than changing the oil.

Thanks for the help.