boat-ed.com
BoaterEd Store      - Help Support This Forum - Join Today!      Hunting/Fishing Stuff
BoaterEd
Username:
Password:
Save Password


Register

Active Topics | Active Polls | Resources | Members | Online Users | Avatar Legend | Statistics
[ Active Members: 6 | Guests: 89 ]  [ Total: 95 ]  [ Newest Member: JohnPadgett ]
 All Forums
 Forums
 Engines, Electric, Plumbing, etc.
 454 Mercruiser Low Oil Pressure / New Owner
 New Topic |   New Poll New Poll |   Reply to Topic | 
Author Previous Topic: Perkins Diesels Topic Next Topic: Battery Isolators  

dsharkss

RO# 25624

Posted - Mar 25 2007 :  10:11:58  Show Profile  Reply with Quote
I recently purchased this boat and I think I may have a problem. When the engine is cold, oil pressure is up around 40psi. Once warm, at idle the oil pressure is reading at or very near 0psi. At about 3500rpm, I'm lucky to have 10psi. If I come down to idle from higher rpm, my low oil pressure alarm starts to click for a short period of time. The engine runs fine, but I do hear a very slight knocking noise that seems to come and go at higer rpms. Just to compicate this a little more, the oil level on the dipstick is about a half an inch over the max fill line. No apparent bubbles after running. This engine has about 100hrs on it and includes a high performance intake, cam and pistons.
So how bad is all of this? Any and all advice is greatly appreciated.

Homeport: Florida

fishless

RO# 10049

Posted - Mar 25 2007 :  10:46:41  Show Profile  Reply with Quote
I know that knocking sound and hope I'm wrong....sounds like the main bearings from what you've described. Make sure your filter isn't clogded and starving the engine. But .what you've described it sounds like the mains


Homeport: DE Go to Top of Page

footloose

RO# 6963

Posted - Mar 25 2007 :  12:28:27  Show Profile  Reply with Quote
First, make sure it is not the PSI guage. IF you didnt overfill it with oil, you could be ingesting water somewhere....reversion, condensation, or oil cooler leaking causing the oil level to rise. I would get a manual PSI gage and test at idle - you should see 40 psi when cold at least and probably in the 20psi range when HOT. If the manual dial reads lower than that, then change oil and filter with quality oil like straight 40 wt and retest. Maybe get the oil tested as well and see if inside the valve covers if you see any creamy colored stuff - a sign of water in oil.

Gone for a while starting Frosty Point Ice Cream Parlor with spouse - but the Harley is running again in trawler mode.

Homeport: Florida Go to Top of Page

Bliss

RO# 2743

Posted - Mar 25 2007 :  12:44:07  Show Profile  Reply with Quote
---and please let us know what happens. Good luck, JS


Homeport: Reef Point Racine, WI Go to Top of Page

fishless

RO# 10049

Posted - Mar 25 2007 :  13:38:49  Show Profile  Reply with Quote
He said the tapping noise increases with rpm increase. That's what clued me in....


Homeport: DE Go to Top of Page

Gregory S

RO# 2620



Posted - Mar 25 2007 :  14:00:57  Show Profile  Reply with Quote
If the oil is overfull, it can aerate while the engine is running and give false oil pressure reading (low).


Edited by - Gregory S on Mar 25 2007 14:01:55

Homeport: Norfolk, Va Go to Top of Page

Two Cats

RO# 6780

Posted - Mar 25 2007 :  18:36:59  Show Profile  Reply with Quote
You have gas leaking into the crankcase. That's why when you check the stick, you show overfill. Unlike water or antifreeze, the oil will look OK until it is seriously diluted with gas. The gas oil mixture thins the viscosity of the oil and causes tappit noise at high RPM and low oil pressure at idle. Sometimes you can smell the gas on the dipstick. The problem is either fuel pump (if mechanical) or carb flooding. Eventually the oil will become so thin the lifters won't work, and engine performance will fail. Ths other problem is the gas washing the oil off the journal bearings and compromising the babbit. Doesn't sound like big trouble yet, but the problem must be found. For what it's worth, Bill


Homeport: Detroit Go to Top of Page

dsharkss

RO# 25624

Posted - Mar 25 2007 :  20:25:03  Show Profile  Reply with Quote
Thanks for all of the input. Ready for the latest?? I took it out today and kept a close eye on the oil pressure and the rpms. I found that if I kept the rpms under 3200 or so, the oil pressure remained around 35psi. Compared to yesterday, that was pretty good. Unfortunately, and on my way back home, I noticed a strong methane smell. I swear I thought there was a gas leak in the area. After about a mile or so, I stopped the boat, lifted the cover over the engine compartment and realized it was coming from my boat. I continued on towards my dock and the boat kicked out of gear. So here is what I think happened....I think that a seal blew out and gear oil blew up through my bellows and ended up in my bilge. Is any of this possible? Did I mention that this outdrive was rebuilt and I put it on two days ago???
This really makes me want to get a sail boat!
I'm still interested in the advice on the oil pressure, but now I also want to know if I have diagnosed TODAY'S problem correctly.



Homeport: Florida Go to Top of Page

MrsRobinson

RO# 19626

Posted - Mar 26 2007 :  21:15:00  Show Profile  Reply with Quote
I am with Twin Cats on this one. We had similar symptons in a 96 3.0 4 cylinder we had in a 18 foot Maxum bow riser. I drained almost 8 quarts of gas and oil out of her. Rebuilt the carb and she was good to go.

Greg
2001 Regal 3780
Twin Horizon 7.4

Homeport: Deltaville, VA Go to Top of Page

MrsRobinson

RO# 19626

Posted - Mar 26 2007 :  21:17:22  Show Profile  Reply with Quote
I am with Twin Cats on this one. We had similar symptons in a 96 3.0 4 cylinder we had in a 18 foot Maxum bow riser. I drained almost 8 quarts of gas and oil out of her. Rebuilt the carb and she was good to go.

Greg
2001 Regal 3780
Twin Horizon 7.4

Homeport: Deltaville, VA Go to Top of Page

jtybt15

RO# 3300

Posted - Mar 27 2007 :  00:36:11  Show Profile  Reply with Quote
Now we need to know what type of drive you have(year, too).

There are a lot of possibilities to your problems.

First you have to determine if the oil is gas or water contaminated. Water is easy. Gas sometimes allows the oil to burn if you put a match to it. put some on a rock or something and try to light it.(or you might be able to smell it)

Also drain some drive oil to see if it's water contaminated. Generally, a drive won't just kick out of gear. Lots of potential problems. Need lots of information to make multiple diagnosis..





Charlie

There is much to be said, in a world like ours, for taking the world as you find it and fishing with a worm.-Bliss Perry, 1904



Homeport: Ca Go to Top of Page

dsharkss

RO# 25624

Posted - Mar 28 2007 :  19:08:15  Show Profile  Reply with Quote
I have a 1988 22' Mach I with the 454 Mercruiser and Bravo 2 of the same year. I will be pulling it out of the water on Sunday. On that day, I will put the engine into gear and see if the saft turns. Has anyone ever heard of a coupler going out and it smelling like sulfer or rotten eggs. There was no apparent smoke, just an incredibly pungent odor. I installed the drive a week ago, but I did use an alignment tool and all seemed to go back together well. What I didn't do is grease the coupler. Being a new boat owner, I wasn't aware that it even existed, much less that I needed to grease it.
Will get back with better info on Sunday. As always, thanks for all of the ideas.



Homeport: Florida Go to Top of Page
  Previous Topic: Perkins Diesels Topic Next Topic: Battery Isolators  
 New Topic |   New Poll New Poll |   Reply to Topic | 
Jump To:
BoaterEd © BoaterEd Go To Top Of Page
This page took 1.03 seconds to load
Forum Guidelines and Privacy Notice

Shop BoatStore.net!     Shop for Toys & Games!    Shop for Housewares!

Boatered.com