Oil Capacity Question For 7.4 MC Owners

[Freebird]

I've asked this question to the factories, both Sea Ray and MerCruiser, and never got a straight answer. Do you folks fill your crankcases based on dipstick readings or the advertised 7 quart capacity in the specs?

My 345DB showed full after 5 quarts, and my 41 Hatt with the same power does the same thing. That was also the case with a couple of other boats I've owned with the same power. I know that overfilling is as bad as underfilling, so I've always split the difference at six quarts.

 

[skolbe]

I base it on dipstick readings with the boat in the water. It seems to match accurately with the specs on my 320, 260 and 215 as well.

 

[Freebird]

I base it on dipstick readings with the boat in the water. It seems to match accurately with the specs on my 320, 260 and 215 as well.

That's fine, but it would appear your 260 is the only boat with the 7.4. So you show full after adding 7 quarts?

 

[skolbe]

It would take almost 6.5 quarts when I owned it. I always assumed the other 1/2 quart was trapped in the oil pan - because I pumped out through the dipstick.

 

[Quint4]

Mine always shows full after 6 qt.s although Merc manual says it takes 7. I have pondered this also. I go by the stick.

 

[roadkingh1]

I go by the dip stick( Backside) for the reading. I have measured the volume of oil that I take out and it is very close to 7 quarts, about a quart difference.

 

[northern]

I putin 6.5 and it indicates full. I drain from the bottom of the oil pan.

 

[Lazy Daze]

Assuming you have the correct dipstick, fill based on the dipstick level.

 

[JVM225]

Go by the dipstick and you can't go wrong.

 

[rondds]

Until this year, I could only get a touch over 5 quarts out of my engines, including the filter contents. I'd measure by dumping the oil that was evacuated into clorox bottles for transport to the disposal tank. I was using this thing (the one on the left)

This year I borrowed a friend's jabsco unit and got darn near 7 quarts out. I didn't realize it would make such a huge difference and I wasn't prepared I had to run out and buy more oil. Great product. Oh, and use the dipstick as your guide.

 

[roadkingh1]

Until this year, I could only get a touch over 5 quarts out of my engines, including the filter contents. I'd measure by dumping the oil that was evacuated into clorox bottles for transport to the disposal tank. I was using this thing (the one on the left)

This year I borrowed a friend's jabsco unit and got darn near 7 quarts out. I didn't realize it would make such a huge difference and I wasn't prepared I had to run out and buy more oil. Great product. Oh, and use the dipstick as your guide.

I have the same king of pump(4 gallon capacity). I bought mine from Defender. It works great. I put a mark equal to 7 quarts and it comes pretty close.

 

[Freebird]

Until this year, I could only get a touch over 5 quarts out of my engines, including the filter contents. I'd measure by dumping the oil that was evacuated into clorox bottles for transport to the disposal tank. I was using this thing (the one on the left)

This year I borrowed a friend's jabsco unit and got darn near 7 quarts out. I didn't realize it would make such a huge difference and I wasn't prepared I had to run out and buy more oil. Great product. Oh, and use the dipstick as your guide.

I used a genuine MerCruiser hand pump on my 345, but I have a dedicated 12V pump on my Hatteras. Never seemed to be an issue on any other boat I've owned in terms of pumping out through the dipstick and getting all of it, but now you boys have me wondering. You would think MerCruiser would come up with a factory installed drain attachment at the bottom of the oil pan, but I guess that makes too much sense.

Nice photo of your 340 by the way. I still think the 345DB and 340DB were the prettiest bridge boats Sea Ray ever built, and I do miss the speed. Mine would cruise an honest 30MPH at 3,500 without the secondaries coming in. I was partial to the single stateroom layout of the 345 myself and liked the larger galley. Then again, it was just me and the wife when I owned mine.

 

[Lazy Daze]

You would think MerCruiser would come up with a factory installed drain attachment at the bottom of the oil pan, but I guess that makes too much sense.

Actually, they do have one! They started using it around 2001. It replaces the standard drain plug with a long hose. The hose has a fitting on the end that can be unscrewed. This can be bought in "kit" form from Merc (I think Sierra makes a kit, as well)... 'course, you have to be able to access your drain plug to install it. That is primarily how we change the oil - suck it out through this hose.

 

[wish2fish]

Actually, they do have one! They started using it around 2001. It replaces the standard drain plug with a long hose. The hose has a fitting on the end that can be unscrewed. This can be bought in "kit" form from Merc (I think Sierra makes a kit, as well)... 'course, you have to be able to access your drain plug to install it. That is primarily how we change the oil - suck it out through this hose.

I thought that hose was so you didn't lose your garboard drain plug! :grin:

 

[Lazy Daze]

I thought that hose was so you didn't lose your garboard drain plug! :grin:

It's a special "2 for 1" deal!:smt001 Doesn't happen very often in the marine industry!!! :lol:

 

[Freebird]

Actually, they do have one! They started using it around 2001. It replaces the standard drain plug with a long hose. The hose has a fitting on the end that can be unscrewed. This can be bought in "kit" form from Merc (I think Sierra makes a kit, as well)... 'course, you have to be able to access your drain plug to install it. That is primarily how we change the oil - suck it out through this hose.

I knew there were aftermarket kits, but I didn't realize MerCruiser had one let alone them having it on their newer stuff (showing my age huh? :grin. Of course we both know the trick would be getting to the drain plug to install such a kit on most twins. Sure would make for a big mess the first time.

 

[Lazy Daze]

Of course we both know the trick would be getting to the drain plug

Amen to that!

 

[rondds]

I had that drain plug/oil change hose on my previous boat. Problem is that unless you changed the oil right after haul out, you had to run with earmuffs long enough to get the oil good and hot for a change. Takes more planning that way. I changed in the water after a run and never used the changing hose.

 

[Lazy Daze]

I had that drain plug/oil change hose on my previous boat. Problem is that unless you changed the oil right after haul out, you had to run with earmuffs long enough to get the oil good and hot for a change. Takes more planning that way. I changed in the water after a run and never used the changing hose.

That is true. The hose is actually a good sized diameter, the problem is the fitting that attaches to the pan - the pathway for the oil to go through is small. The stronger the "sucking" tool that one uses the better. But, let's face it, none of us is likely to spend a $1,000 on a 20-gallon, shop-air pressurized machine to change oil at home. Sometimes I get spoiled with the tools at work when it comes to doing things at home or for friends and family!

 

[rondds]

Dennis
The Jabsco unit really kicks a$$. It's almost like a reverso. I've been changing oil in boats my entire life, from when I was a kid with my dad to now, on my third boat - and it's always been with a some sort of manual suck-out thing. What a colossal waste of time. Granted, it aint quite auto-shop caliber, but this Jabsco is a a close second!