Performance of Mercruiser 5.0 on 2005 320.

Asta

Hi All,

Brand new to the forum.  I am finding it very helpful.

Strongly considering buying a 2005 320 with Mercruiser 5.0s.  Can someone advise on the performance of this boat.  I am concerned it is a little under powered.  I am told cruising speed is 20 MPH.  My 250, with a 5.0, couldn't maintain plane at that low a speed.  I would like to know what this boat's rpm would be at 27 MPH, and also what the minimum planning speed would be with an average load,(full tank of gas and 2 adults).

Thanks,

Andy

Lake Simcoe, Ontario 

Dream_Inn

well, I used to own a 2002 310 with 5.0 MPIs.  The boat would top out over 40mph.  Cruising speed was just over 30mph.  We took that boat on many trips, loaded up for 10days and no issues.  Owned it for almost 7 years without any issues.  320 is a very similar boat.  Few things are moved around different, like generator is in front center of engine room - making front berth just a tad shorter.  TV cabinet is in aft portion of galley.  Everything is very accessible on that boat and just get a decent survey before buying.  Any specific questions, just ask.

Asta

Thanks, that does help.

Michael T

@Asta, Rinker sold a lot of 320s with 5.0s in them.

If buying that size combination I would be leery of Volvos with the older drives, which have huge problems that have been discussed at length on this forum.

Rinker has also equipped 320s with Volvo diesels - again I'd look at the outdrive model.

I have been on a 320 with twin 5.0 Mercruisers. it was okay, nothing special though. Remember it's a pretty hefty boat. Add gear, food, drink and friends........

However, I was on a 320 with twin 350 Mags I'm not sure of the year 2008 or 09 BUT - THAT was really cool. It outperformed the one with 5.0s hands down. the acceleration and performance on plane were noticeable.

I have seen many, many boaters who regret getting the smaller engine packages but never heard anyone complain that their engines were too powerful. BTW the guy who had the twin 350 Mags said he got about 15% better gas mileage than his buddy with twin 5.0s

If you are looking you have the ability to get what you want if the price is right for you. Why not get the best package you can? For me that would be twin Mercruiser 350 Magnums.

BTW - I had a 2013 EC 310 with twin 350 Mags....so similar to what you are looking for.

320 with 5.0s - think okay, but a bit slow. Now think 320 with Mercruiser 350 Mags,..... think rocket ship.... LOL.

Anyway, that would be my 2 cents.

Asta

Thanks for the advice.  I would prefer the 350s, but they are far and few between up here.  This particular boat looks like a good deal.  If it had the 350s, I would own it already.....

Michael T

@Astra, you will be okay with the 5.0s. Rinker made a lot of them and I never read of underpowering complaints. It's just my way to want a bit of extra HP insurance LOL.

The 320 is an amazing boat. Tough and fast for its size compared to other brands. A lot of interior and cockpit space for the size too.

The GOOD news - you aren't looking at the dreaded older style Volvo self-destructing drives!

Good luck with the purchase! Please let us know how it plays out!

summerx

I have a 310, which is the same basic boat as the 320 with merc 5.0 BIIIs.  it actually performs quite well for what it is.  It is not going to be a speed boat, but I cruise around 30-32 and can hit 40WOT.  I use it to pull my kids on tubes, wakeboards, ski's, etc.  I think I generally cruise around 3600rpm, which put me right around 30.

Michael T

@summerx, that's decent for sure! I have a bit of a HP addiction, tried counselling but it didn't work! :-)

Dream_Inn

I have gotta disagree completely with MT on this one.  It may be different for the newer 310s, but the older 310/320s, the 5.0 MPIs are fantastic with that boat.  You will not regret that power combination.  I will agree to go with the B-3 drives.  I had that boat 7 years, with 2 kids and food for 10 days & stuff for the beaches and all.  We took it from Annapolis, out in the ocean to VA beach.  Fantastic boat!

Summerx is dead on.  3600 rpm was perfect speed and around 30ish (I think I went more around 32mph, maybe a bit higher rpm, but usually had more weight in her).

Again, I know that boat and every inch of it inside and out.  It is the boat that got me into Rinkers.  A friend had bought a 2001 310 brand new and I used to work on it long before I got mine in 2006.  Everything is maintainable and a lot of boat for the money.  I still see the owner of my old 310 from time to time and his family loves it (they have 3 kids).  They load her up even more than we did!

Michael T

@DI you may wish to read the whole thread.....I did say that I thought the 5.0s would be okay.

Dream_Inn

I did read all that you wrote...just couldn't ignore the 'bit slow' comment.  I think any boat that is loaded for 10 days and can still hit 40mph isn't really slow.  Guess it's just a difference in opinion

Asta

Thanks all, I'm calling the broker today to put in an offer.....

Dream_Inn

Good luck Asta and please let us know how it goes.  Hopefully you're either getting a great deal that you don't need to worry about sea trial or get the chance for a sea trial in the spring.  I have to say, I wasn't able to sea trial mine before I bought, but I knew how the boat handled with the drive package and made sure I worked any issues into the deal.

Michael T

@Astra, since you can't sea trial the boat it IS a good idea to see if the seller will offer any kind of warranty. I once sold a boat to a nervous buyer. I knew the boat was just fine. I told the buyer I would pay 50% of any REQUIRED repairs up to $1,000.00. That relaxed him with some peace of mind. I made the sale. I heard from him at the end of the next summer. He had seen my new boat and said "When you got to sell your new boat will you call me first?"

It costs nothing to ask the seller to put in writing on the sales slip that he will offer some sort of warranty - may I respectfully suggest that he gives that in writing. Of course if the seller does not seem to have faith in the boat?

Good luck. Let's see some pictures if you close the deal!

212rowboat

MT's right... 5.0's are underpowered.... 350's would be too... 383's are... 496/502's? Underpowered... a GE90-115B would do the trick... just one of them will suffice.. 700+ MPH at an altitude of 35k feet... 

there is no such beast as a properly powered anything that has power... 

well, sail boats can be overpowered... folks usually avoid that kind of power with their sail boats, though, I don't understand why....

"I'd rather burn out, than fade away!"

Handymans342

Where have you been 212??????

walleye

5.0s on the 320 are just fine. You won't have any power deficiency problems. That's what I have in my 320 and it is plenty quick on the top end (40mph) and gets out of the hole just fine. Agree with what the others said about the sweet spot - right about 3600rpms which should get you 27-30mph depending on weight and tide variables.  

Asta

Thanks again all.  Good to know the 5.0s will be enough.

steevo

Did you end up getting that boat Asta?