Low oil pressure
09-25-2007, 10:26 PM
#21
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No alarms and no guardian mode. No change in performance at all when this happens. The pressure just slowly drops off from 40psi while getting on plane and as the rpms go up. Then it just flutters between 20 and 25. I thought the same thing about trying to hook up a scan tool but I don't know anyone than has one. I'd actually buy one if I could find one cheap enough. I'm sure it would come in handy to have one.
I drained about a qt out tonight and plan to get it in the water no later than the w/e. I'll check the oil level at rest in the water and make sure I'm in the range but not even close to over before I fire it up and run it. If it still happens I think I'll replace the filter and throw in new Merc synth blend and try it again. Again making darn sure I'm not over. If it still does it then I'll be forced to add a mechanical gauge just to make sure it's not a gauge or sending unit problem. A scan tool would make this much easier thats for sure.
Hopefully I'll have some answers soon and it will just be operator error. I could handle that even after 30+ years of boating.
I know it's under warranty and nothing against the dealers but I just hate to take my boats to the shop unless I absolutely have to. Especially a brand new one like this.
Thanks for input!
I drained about a qt out tonight and plan to get it in the water no later than the w/e. I'll check the oil level at rest in the water and make sure I'm in the range but not even close to over before I fire it up and run it. If it still happens I think I'll replace the filter and throw in new Merc synth blend and try it again. Again making darn sure I'm not over. If it still does it then I'll be forced to add a mechanical gauge just to make sure it's not a gauge or sending unit problem. A scan tool would make this much easier thats for sure.
Hopefully I'll have some answers soon and it will just be operator error. I could handle that even after 30+ years of boating.
I know it's under warranty and nothing against the dealers but I just hate to take my boats to the shop unless I absolutely have to. Especially a brand new one like this.
Thanks for input!
09-29-2007, 07:16 PM
#22
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Well I eliminated two possibilities today. I changed the oil and filter and went out on the water. Same deal.
Oil level was right in the middle between full and add so I would think that takes care of the airation from too much oil possibilty and the new filter eliminates it being a bad filter. I have a new Merc sending unit on the way and also a new Livorsi oil pressure gauge. Hopefully I can get them installed next week and see if either one of those takes cares of it as I know I'm running out of weather here to get this diagnosed.
Today the oil pressure would run about 40 (steady) @3000 but much past that the pressure would start to drop and the needle would start to flutter. Idle was at 20 lbs but if I bumped it up to 900 rpm or more the needle would jump to 40. It did seam to get slightly worse the warmer the oil was on the oil temp gauge. If the new sending unit or the new pressure gauge doesn't do it then it goes to the Merc dealer. I have a mechanical oil pressure gauge but couldn't find a good place to tie it in on the block. Getting to and replacing the sending unit is going to be a challenge in itself. It's on the port side on the rear of the engine somewhat hard to get to.
I fear the worst. Almost ready to pop the $399 for the Merc scan tool from Rinda.
Oil level was right in the middle between full and add so I would think that takes care of the airation from too much oil possibilty and the new filter eliminates it being a bad filter. I have a new Merc sending unit on the way and also a new Livorsi oil pressure gauge. Hopefully I can get them installed next week and see if either one of those takes cares of it as I know I'm running out of weather here to get this diagnosed.
Today the oil pressure would run about 40 (steady) @3000 but much past that the pressure would start to drop and the needle would start to flutter. Idle was at 20 lbs but if I bumped it up to 900 rpm or more the needle would jump to 40. It did seam to get slightly worse the warmer the oil was on the oil temp gauge. If the new sending unit or the new pressure gauge doesn't do it then it goes to the Merc dealer. I have a mechanical oil pressure gauge but couldn't find a good place to tie it in on the block. Getting to and replacing the sending unit is going to be a challenge in itself. It's on the port side on the rear of the engine somewhat hard to get to.
I fear the worst. Almost ready to pop the $399 for the Merc scan tool from Rinda.
Last edited by Pain_Killer; 09-29-2007 at 07:18 PM.
10-07-2007, 06:50 PM
#23
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Looks my low pressure problem wasn't really low oil pressure. In the essence of time I replaced the sending unit and oil pressure both and took the boat out for a run Friday night. The gauge stayed steady and did not flutter at all even during a hard run at 5000 rpm and with oil temp a little over 200. Oil pressure ran steady between 40 and 50 psi at WOT and a hair over 20 psi at idle after the hard runs. As oil temp went down the oil pressure would come up at idle. Unfortunately I will never know whether it was the gauge of the sending unit causing the problem. I'm just glad it wasn't a pump problem or other internal issue.
Thanks for all the help and suggestions!
PK
Thanks for all the help and suggestions!
PK
10-07-2007, 09:25 PM
#24
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first thing first>>> validate the problom, remove the oil
sending unit, screw in a manual guage on a short hose and
verify that you really have an oil pressure problom and not an
electrical prob with the guage or s-unit. Good mechanics always check the simple first before going to the complex.
sending unit, screw in a manual guage on a short hose and
verify that you really have an oil pressure problom and not an
electrical prob with the guage or s-unit. Good mechanics always check the simple first before going to the complex.
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