Oil Question???
03-07-2019, 12:46 PM
#1
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Thread Starter
Oil Question???
I have a 2001 Fastech 312 with twin 6.2 MPI 320 hp motors & mostly run it at LOTO where water is 80 deg & air is that or more. We run at 3500-5000 Rs all day.
I bought the boat last summer & couldn't get the previous oil being used. When I changed the oil I put Merc 25/40 in them, but my oil pressure was not the same after motors warmed up as before the oil changes. So I'm thinking of going with Mobil 1 15/50 & hoping I'm good after that. What's your opinions of me running 15/50 in 377s & what filter would you all recommend?
Motors have around 250 hrs.
Thanks
I bought the boat last summer & couldn't get the previous oil being used. When I changed the oil I put Merc 25/40 in them, but my oil pressure was not the same after motors warmed up as before the oil changes. So I'm thinking of going with Mobil 1 15/50 & hoping I'm good after that. What's your opinions of me running 15/50 in 377s & what filter would you all recommend?
Motors have around 250 hrs.
Thanks
03-07-2019, 01:19 PM
#2
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iTrader: (1)
Mobil 1 15w-50 will be great. Be Happy. 
Last edited by SB; 03-07-2019 at 01:19 PM. Reason: re-read the OP
03-07-2019, 04:24 PM
#3
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Thread Starter
What's the best & biggest filter I can run?
With the small oil pan I want to run the biggest filter I can...
More oil the better!
Thanks
With the small oil pan I want to run the biggest filter I can...
More oil the better!
Thanks
03-07-2019, 06:44 PM
#4
03-07-2019, 08:22 PM
#5
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On any of the small blocks that get run hard we use the Mercury Racing 25w-50 engine oil and Mercury Racing oil filters. Make sure there is enough hatch clearance for the taller filters. The heavier oil does help to maintain a little more oil pressure at temperature.
03-07-2019, 09:26 PM
#6
Charter Member # 55
Charter Member
Mobil 1 15w-50 is all I have ran for about the last 1000 hrs on 3 different boats.
I run the Mobil 1 M1-302 filters. They are the same size as Merc filters but filter better and flow more..
I run the Mobil 1 M1-302 filters. They are the same size as Merc filters but filter better and flow more..
03-08-2019, 08:38 AM
#8
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I've been running Amsoil 15w50 racing oil with a Donaldson P550832. I run pretty hard for long periods of time with an oil cooler that's smaller than it should be, my oil can sit at 280+ for 30 minutes while I run across Lake Huron. No oil breakdown, no change in pressure from old to new. I've done tear downs just to see how my motor is doing and it still looks like new, no varnish or sludge. Bob Teague ran Amsoil racing oil all season in his race boat with no measurable wear after a full season of racing. FWIW
