7.4 Volvo single prop

[tobebent]

I have located a very clean 2003 Crownline 230BR with the 7.4 EFI Volvo single drive prop. I have only owned merc engines and drives, so I absolutely know nothing about the Volvo's and had a few questions for the experts here. I asked the seller what drive he had, but didn't know. He did know that it was a single prop drive. What drive model do you expect this boat to have with this engine package. Can you add a dual prop system to this drive? Are the Merc and Volvo engines the same (Chevy big block 454 MPI )? Any known issues with the 7.4 EFI engine. Would there be a significant fuel economy difference between the 7.4 EFI and the Merc 350 Mag? What about resale value with the volvo package vs Merc?
Thanks in advance

 

[tpenfield]

Re: 7.4 Volvo single prop

Welcome to iboats . . .

I can answer a few of the questions, others will chime in as well.

The engines are substantially the same - based on the GM 7.4 / 454. Merc & VP essentially make the outdrives and marine specific parts.

You could probably not modify the single outdrive to be a dual prop, that would be replacing the drive. Not worth it IMHO.

There is no such thing as fuel economy with boats, but generally, the bigger engines do not use significantly more fuel to power the same boat. A 350 Mag may be a good alternative to a 7.4, but you will not get rich with the fuel savings, if any.

Resale value is negligible difference, based on the age, it is more about condition of the particular boat/engine combo.

Based on what you described, there is nothing to be afraid of, so long as boat and engine are in good condition. (think Marine Surveyor)

Let us know how it goes.

 

[Don S]

Re: 7.4 Volvo single prop

I don't recall the Volvo 7.4 EFI ever having a single prop drive on it from the factory plus the 7.4 was not used after 2000 with the EF models. In 2001, the 8.1 was used. So it's really hard to say what is in the Volvo powered boat for sure.
If it is the SX drive, the lower unit (not the upper) can be replaced to convert to DP.

As far as fuel economy in a 23' boat, there would be significant savings with a 350 MPI over the 7.4. Those big blocks like their gas.

The DP option will also increase fuel mileage by about 25% according to Volvo, in real life with boats I have converted from single to DP, this seems true as well according to the customers.

As far as boat value, this is the IO forum where we deal with the engine and drive, might want to ask that question in Boat Topics and Questions (not engine topics) , that kind of info is asked all the time there, and a lot more people visit that forum as well, but may never come to this forum.

 

[tobebent]

Re: 7.4 Volvo single prop

I don't recall the Volvo 7.4 EFI ever having a single prop drive on it from the factory plus the 7.4 was not used after 2000 with the EF models. In 2001, the 8.1 was used. So it's really hard to say what is in the Volvo powered boat for sure.
If it is the SX drive, the lower unit (not the upper) can be replaced to convert to DP.

As far as fuel economy in a 23' boat, there would be significant savings with a 350 MPI over the 7.4. Those big blocks like their gas.

The DP option will also increase fuel mileage by about 25% according to Volvo, in real life with boats I have converted from single to DP, this seems true as well according to the customers.

As far as boat value, this is the IO forum where we deal with the engine and drive, might want to ask that question in Boat Topics and Questions (not engine topics) , that kind of info is asked all the time there, and a lot more people visit that forum as well, but may never come to this forum.

I did think that a 7.4 in a 03 model boat was odd. Most of the 230br that I have been finding have 5.0MPI with the B3 and Volvo drive, but feel the boat with that set-up will be underpowered for watersports use that I will be using it for. I have found a couple with the 350 mag but these are priced out of my budget. I wonder if the 7.4 set-up in the 03 could be a replacement engine? I will do more research. Even if the guy was wrong thinking he had a 7.4 instead of the 8.1, and I replaced the drive to DP, I might as well spend the extra $ and get the 350 mag. In the long run I think I would actually save money with the 350 mag set-up instead of switching drives and the fuel economy. I do under understand that there is really is no such thing as MPG in boats, but I think the big block would be GPM instead of MPG. There is alot of knowlege on this forum, and I appreciate everyones input.

 

[Don S]

Re: 7.4 Volvo single prop

I thinkactuallyd actualy save money with the 350 mag set-up instead of switching props and the fuel economy. I do under understand that really is relly no such thing as MPG in boats, but I think the big block would be mGMng it GPM. There isknowledge knowlege on this forum, and I appreciate everyones input.

Might want to edit that part.

 

[tobebent]

Re: 7.4 Volvo single prop

I did think that a 7.4 in a 03 model boat was odd. Most of the 230br that I have been finding have 5.0MPI with the B3 and Volvo drive, but feel the boat with that set-up will be underpowered for watersports use that I will be using it for. I have found a couple with the 350 mag but these are priced out of my budget. I wonder if the 7.4 set-up in the 03 could be a replacement engine? I will do more research. Even if the guy was wrong thinking he had a 7.4 instead of the 8.1, and I replaced the drive to DP, I might as well spend the extra $ and get the 350 mag. In the long run I think I would actually save money with the 350 mag set-up instead of switching drives and the fuel economy. I do under understand that there is really is no such thing as MPG in boats, but I think the big block would be GPM instead of MPG. There is alot of knowlege on this forum, and I appreciate everyones input.

Sorry about that, spell check does more harm than good

 

[tobebent]

Re: 7.4 Volvo single prop

I have a few pics. Drive looks to be a SX.

 

[Don S]

Re: 7.4 Volvo single prop

It is a gray engine, so it's 2000 or earlier, and it is an SX.
I have to wonder what was in that boat originally, as I said, a single prop was not used with the big blocks, and why would anyone need a whale tale on a 23' boat with almost 400 hp?

 

[Tail_Gunner]

Re: 7.4 Volvo single prop

Hold the phone Alice....There is no marine 350 that can hold a candle to that engine..horsepower maybe a little close.There is a serial number on that engine post it plz..and the main body computer post all of those numbers. You may have more engine and boat there than you thought you had ..a bunch more. Looking at it... is that a mpi motor..not tbi.

The only possible downfall here would be a sx drive with a 400hp motor and 450 lbs ft of touqre...:grouphug:

 

[Don S]

Re: 7.4 Volvo single prop

It's either a 360 or 405 hp motor, and the drives physical capabilities are not the question here. The problem is the 7.4 MPI engines never came out with a single prop drive, nor is a 2000 engine likely to be found in a 2003 boat. So things are not as a new boat should be, and a lot of that HP is wasted on a single prop drive, why they didn't match a single prop drive with that engine at Volvo.
Someone probably took a boat with a small block, and swapped engines to the big block.
It's not normal or stock, that's the problem with this setup. Not the HP of the engine.

 

[Tail_Gunner]

Re: 7.4 Volvo single prop

Well this would be a easy to thing to determine if this conversion was done right. It should have a mefi as you know..was the mefi programed for the 7.4..how many hours..the info is stored in the ecu. That would be a great combo and a lot could be done with it as far as fuel econ. One big asset would be carrying passengers your not going to pull down a 7.4 nearly as much as 5.7 with weight..It would be amazing actually crazy to see a duo prop 350 stay with a single prop 7.4 in pulling or speed.

Tabs and a new tune. mounting a duo on the sx would make that one hell of a ride..As long as the conversion was done right....Ive seen many people spend crazy money on there boat's and being a crownline bowrider it was a nice peice of change to start with..i doubt someone hacked that together.

 

[Don S]

Re: 7.4 Volvo single prop

He doesn't have a running problem, he doesn't even own the boat. He is asking about it. The problem is not if the engine is good or not, or if it will work or not. The problem is it's not the right year for the boat, and it's the wrong drive for that engine.

The point being, he should take that into consideration if he decides to buy that boat.

For all we know, it could be the original engine, and it's actually a 2000 or 2001 boat and not a 2003. (HIN would tell that) it could also have had a damaged lower and was replaced with a single prop lower because it was cheaper.

A Volvo dealer hooked up to Volvo Penta's dealer program could verify the hulls HIN number with the engine serial number and drive serial number and see what matches with what.

 

[tobebent]

Re: 7.4 Volvo single prop

I contacted the owner and the boat is a 02 not a 03. He is the 2nd owner of the boat. He did believe that this engine was original to the boat because he didn't have it changed and the 1st owner didn't hint that it was not the engine the boat came with. I don't doubt the owner because he has been very good to work with and honest. Don S. did point out the whale fin on the drive. That tells me possibly that maybe the boat was hard to get on plane because of a small block and a single prop. The 2nd owner did give me the 1st owners phone#, so I am still trying to get some info. The owner is going to get me the HIN# and the engine serial#, so maybe we can figure out this mystery. If this motor is actually a MPI, wont this still be a gas guzzling beast? I would not have a problem installing a duo on this boat for fuel economy if I end up owning it. I just want to find out what we have here so I can make a educated decision/ offer. I have more pics of the boat and it is very nice and clean with 300ish hours.

 

[Don S]

Re: 7.4 Volvo single prop

It's MPI, that is obvious just by looking at the engine. The fact that is gray says it's 2000 or earlier.
Drives looked the same for all the SX-M drives.
If you don't get answers from the original owner, get the Serial numbers of the engine, drive, and transom shield, along with the hull HIN and contact a certified VP dealer with the online Volvo program, they can track each SN and HIN to see what went to what.

Big blocks use a LOT more fuel than small blocks, just the nature of the beast. Carbed or MPI.