Rough Engine low Oil Pressure

[Seevee]

All,

I have a 7.4 mercruiser, carb, Bravo three that was rebuilt by a local shop about a year ago with perhaps 40 hours on it. 270 Sundancer.

It has been running a slight bit rough since the overhaul. (not bad, but not smooth).

After a high speed run, when idling in, the oil pressure goes to almost zero and the alarm sounds.

I can get the pressure up by running the RPM up to ~1200.

Temps are fine.

Also, my top end is about 7 or 8 kts slower than the previous engine. (30 vs 38).

Any ideas on what the issue is?

Steve

 

[JustJason]

Re: Rough Engine low Oil Pressure

Have you started by checking the oil yet? What was the oil level? Was it to high? To low?

Tell us what you've done on your end so far to diagnose your problem.

 

[westportfish]

Re: Rough Engine low Oil Pressure

I had a low oil pressure problem on my 427 Chev in my Donzi after a fresh rebuild. my oil temp was a constant 190 degrees with the original engine but would climb to 250 with the new one and would cause the oil pressure to drop at a idle after a long run. The problem was corrected when I replaced the high volume oil pump that was installed during the rebuild and replaced it with a stock unit. I would run Mobil 1 15-50 with the high volume pump and that helped with idle oil pressure until I was able to swap out the oil pump.