Oil changes in Inboards.

polarisrider1

New member
This is an Amsoil question. What should the oil change frequency be for a pair of 350 cid's with EFI, putting out 300 hp ea. Mercruiser V drives using Amsoil Marine 4 stroke oil and quick silver filters.Also what is the part number for Amsoil filters for this application. normally I change oil each fall with standard quicksilver oil but was wondering with low hrs on boat if maybe 2 years was fine? put less than 25 hours on boat this year.normally put on around 100 hrs. per year.
 

whitedust

Well-known member
I changed mine evey year thought moisture might get in oil for marine application. I had oil change kits with hose that I could drop thru boat water drain plug. Always can pump oil too but does not get sludge out. Filters were always a PIA in confined area so now have 150 Etek outboard which automatically foggs engine at end of season. With inboards better safe than sorry & I always took all water hoses off as well to drain dry so no freeze up. Used M1 fully syn. Happy I don't have to deal with that any more.:)
 

snoluver1

Active member
I'd say a marine engine sitting in the water is probably a pretty humid environment. Might as well just change it. If you can afford to put gas in that thing, why not change the oil. If you don't run it much, your not really taking advantage of the high dollar synthetic. Might as well put el-cheapo dead dinosaurs in it and change it every season. jmo
 

polarisrider1

New member
This is the first year with Amsoil in the boat engines. It did cost a bit. Engines are big dollars, so I will change and rethink the oil choice again. I did not run the boat like in the past and don't plan to run them much next year. So maybe I over did it.
 

wags

New member
Change them as you have been doing before you switched oil types, being down in the bilge there is too much moisture to worry about.
 

doomsman

New member
To disagee, I would take it and get it hot or run it with a hose,
change the filters and top off the oil.
Fog the top end with regular oil and store it.
 

eao

Active member
The longest period for any oil change is one year, you should change oil at least once a year preferably before storage. Oil is designed to capture and hold combustion by-products to be removed by the oil filter so its a good idea to change it yearly. Its cheap insurance as you never know. I know some who planned to use their boat the next year and it ended staying in the garage for many years.

There are several possible AMSOIL Ea filter that would fit this engine. If you can give me more information on the engine. I had good luck finding a filter for a Indmar Chevy engine. That takes an EAO25 which is a common 350 engine oil filter.

Does it give you a GM or AC Delco filter number in the owners manual? I have a huge cross reference catalog to cross every filter to an AMSOIL or at least a Wix or Donaldson if no AMSOIL but I have yet to find a GM engine that AMSOIL does not have an EAO filter for.
 
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polarisrider1

New member
I do have a quicksilver number of 35-802885Q and a Fram number of PF-30. Also a Sierra oil filter number of 18-7824. Fuel filter is a Quicksilver 35-802893Q or a Sierra 18-7945. I will change oil and fuel seperater/fuel filters as I have every fall. Just very low hours on boat this year and it is a huge expense for 10 qts. of M1, quiksilver or amsoil and 4 filters.
 

eao

Active member
PF-30 appears to be a AC Delco number and not a Fram




AC Delco PF-30 = AMSOIL EAO25
Fram PH-30 = AMSOIL EAO25
Sierra 18-7824 = AMSOIL EAO25
35-802885Q = No AMSOIL filter*


*Is Quicksliver a Mercrusier filter brand? IF it is, the Wix cross reference shows this filter is 1/2 inch shorter than the filters above. Clearance may be an issue with a 1/2-inch longer filter.

Manufacturer Part NumberManufacturerAbbr.WIX Part NumberLead Time
35802885QMERCRUISERMRC 51086

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Yup, that is a huge expense. If it were me and I was using AMSOIL, I would park it and not worry. If it was using any other oil, I would worry because those are commodity oils and AMSOIL is a specialty oil produced with the best available base oil and additives. Its your call.
 
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polarisrider1

New member
Thank you eao, I ment PH-30 for fram, amd PF-30 for AC filter. The longer filters do fit. I have a dry sump set up with filters on independent mounts. looks like the Chevy 350 filters of days gone by are what it takes. Sea Ray put the Quicksilver filters on it stock. I suspect the Sierra filter number 18-7945 is the same as 18-7824 but shorter. I suspect with only about 20 hours on the oil change, less than 600 miles, I will not change oil at this time. p.s. I run Amsoil in everything I own, even the push mower. My Harley runs and idles so much better with it. What I like about Amsoil is it fine tunes their oils to motor specifics. My wifes bike which is liquid cooled takes a different oil. My hemi take different oil than wife's Buick Rendevous.
 
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eao

Active member
Btw - The Wix filter that cross's to these filters (Ea025, PH & PF 30) is 51069. If you are Preferred Customer/Dealer you can get that filter from AMSOIL for <$6.
 
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