Repower questions

[SCORPIO]

As some of you may recall, my port engine suffered water ingestion on the last start up of the season, it was hydrolocked. Since its raw water cooled and I boat in salt water, I have pulled the engine and decided it should be replaced since it had salt water and oil mix running thru the bearings etc.
Boat is an 89 300Da with twin 5.7's, 260 HP and Alpha One outdrives.

I plan to replace the port fuel tank while the engine is out of the way due to its age.


Now I know a repopwer isn't cheap but, we love this boat and have made may improvements over the years and and is in otherwise great shape and we plan to keep it for a long time. Our kids are almost grown and we will not need to upsize.

So, I've been looking at engine choices since I have all winter to plan this out. One thing I want to do is to put closed loop cooling on the replacement since I boat in salt water and have the room for the setup. I've been looking at several options, reman long blocks, new long blocks, semi complete engines and crate motors. The cheapest route is a reman long block from Jasper etc. I don't know how much faith I have in putting closed loop cooling on an old block that has been cleaned, will it fill my heat exchanger with scale?

A new long block appeals to me from a warranty stand point as well as being free of internal corrosion. I see several horsepower options 260 and 325. I will admit that the inner Tim Allen in me wants to do the 'more power' route but due to finances I can't spring for a pair of engines at this moment. I'd like to hear opinions.
I was toying with the idea of replacing port engine spring 2015 and starboard spring 2016. Thinking about going the 325 HP route. I know this is a mismatch for the first season and am wondering what would happen if I actually did this. If I don't reprop, and run both engines at the same RPM, would not the boat perform as if the engines were matched? Would I be making a constant right turn? I know WOT would not be an option due to the mismatch, but I haven't done a WOT run in several years. I'm guessing my throttles would be 'misaligned' due to the new engine having a different power curve but if all I have to do is juggle the sticks, its only for one season.


Do you think this is a doable plan or should I just put in a 260 and move on?
Ultimately, after the second engine, I'd reprop with four blade stainless and more pitch to take full advantage of the increased power.

This is as much a thought experiment at this time as it is a plan so I'm open to any and all suggestions/comments. I'd rather hash it out here during winter than to throw money away in the spring.

 

[src]

Keep in mind that since you are running Alpha One outdrives, they have a maximum rating of around 300HP (IIRC). Also, you might have to change the gear ratio inside the drive if you step up to a stronger engine. Always consider the entire system, not just the one part you are looking at right now.

 

[hottoddie]

I would keep my eye open for a "pair" of FWC running take outs and replace both motors at the same time. Craigslist or ebay have them here and there. I'd stay with the 260 hp carbed motors with the alpha drives. Good Luck.

 

[Lazy Daze]

In regards to the HP, the "260" that your engines are currently rated at is not really 260. Back then, the rating was taken at the engine, whereas nowadays the HP rating is taken at the prop. This is true for all of Merc's existing fleet - but I couldn't say what another retailer is quoting - you could ask them. Probably about a 30HP difference, give or take, by the way. Also, given the age, the current engines (well, engine) are likely not putting out the same amount of power they had when new.

You're correct that if you put in a higher HP engine on the port side that you'd simply have to manage your power to match RPM's with the starboard. Once up on plane it's not so hard. The harder part (at least until you get used to it) will be getting to plane since you'll have to move the sticks at different rates.

The only suggestion I would make is to consider a "full" closed cooling system instead of the typical "half" system. The typical system does not include the manifolds in the AF loop - the full system does.

 

[JVM225]

I did both of my motors a couple of years ago when I started having problems with the starboard one. It was a big investment, but I really like the boat and I couldn't replace it with another of the same size with new motors for what it cost me.
I got brand new 275 HP Mercruiser replacement motors that came complete from flywheel to circulator (water) pumps, and from oil pan to flame arrestors. They came with complete ignitions including spark plug wires, and even had oil in them from the factory. I had to re-use my brackets (which I wire wheeled and re-painted), and I opted to put new peanut sized starters and new alternators on before the motors went in. New belts and hoses also went on to avoid problems down the line.
Back when I bought mine I got them from Michigan Motorz. They were listed under "partial engine packages". The configurations may have changed over the last few years, but they were new vortec marine motors made by Mercruiser. When I was looking at them, just about any dealer that sold Mercuiser motors had them. The owner at Michigan Motorz is very knowledgeable and great to deal with. I wasn't too crazy about the salesman he handed me off to once I decided what I wanted, but by that point the owner had me very well informed about my choices. His (the owner's) guidance was right on the money.
I found a good used counter rotating drive for the port side that winter, and did that modification while I was at it.
The other things I did were half FWC systems (full systems would have needed separate water pumps mounted on the motors) with new manifolds and risers, and I also went for remote oil filters. The remote oil filters really make life easier since the filters in the stock location are so close to the stringers, and almost impossible to maneuver out without making a mess.
Everything was done by April of 2012 and I've thoroughly enjoyed the reliability of the new power for the last 3 seasons.
It hurt a little bit when I was doing it, but it was really worth it to me because the boat has served me so well since then.
I was looking at the motors that had higher HP when I was deciding what to go with, but went lower because of the Alpha's limitations.
Honestly though; between the fresh motors, counter rotating drives, and the 15 1/2 X 17 stainless props I went with, the boat handles fantastically and is plenty fast enough. It really jumps out of the water up on plane now.

 

[AFD]

due to money being toed up in our construction project right now i was back and forth about what to do as well. lost our port engine this year as well. for money reasons not for performance reasons we are replacing a 5.0 carbed with the same long block.

i was toying with the idea of 350's one one year and one the next. just not sure we will be out of the hole next year with our second child due in july. twin 350 mags would be great in my 290. they would even save some fuel if i could keep them out of the throttle while grinnning.

if it is one seaspn and you know how to handle your boat well, the different engines wont be an issue as long as you remember slow throttle on the more powerful one to prevent over-revving. good' luck

 

[suss1173]

I'm contemplating the same project and still undecided on which HP to choose. However, I don't see the savings on the re-man's enough to justify it (imo).
What ever I purchase will likely be from MI Motorz, I like the "small business" vibe and personal attention they give.

 

[Air O'Nautical]

I'm contemplating the same project and still undecided on which HP to choose. However, I don't see the savings on the re-man's enough to justify it (imo).
What ever I purchase will likely be from MI Motorz, I like the "small business" vibe and personal attention they give.

I can vouch for the personal service from Michigan Motorz.
When they made a mistake sending me 2 incorrect alternators ... They sent out the correct parts immediately after I called them, along with return shipping labels for the wrong parts.

Best of luck with your project,

 

[Air O'Nautical]

As some of you may recall, my port engine suffered water ingestion on the last start up of the season, it was hydrolocked. Since its raw water cooled and I boat in salt water, I have pulled the engine and decided it should be replaced since it had salt water and oil mix running thru the bearings etc.
Boat is an 89 300Da with twin 5.7's, 260 HP and Alpha One outdrives.

I plan to replace the port fuel tank while the engine is out of the way due to its age.


Now I know a repopwer isn't cheap but, we love this boat and have made may improvements over the years and and is in otherwise great shape and we plan to keep it for a long time. Our kids are almost grown and we will not need to upsize.

So, I've been looking at engine choices since I have all winter to plan this out. One thing I want to do is to put closed loop cooling on the replacement since I boat in salt water and have the room for the setup. I've been looking at several options, reman long blocks, new long blocks, semi complete engines and crate motors. The cheapest route is a reman long block from Jasper etc. I don't know how much faith I have in putting closed loop cooling on an old block that has been cleaned, will it fill my heat exchanger with scale?

A new long block appeals to me from a warranty stand point as well as being free of internal corrosion. I see several horsepower options 260 and 325. I will admit that the inner Tim Allen in me wants to do the 'more power' route but due to finances I can't spring for a pair of engines at this moment. I'd like to hear opinions.
I was toying with the idea of replacing port engine spring 2015 and starboard spring 2016. Thinking about going the 325 HP route. I know this is a mismatch for the first season and am wondering what would happen if I actually did this. If I don't reprop, and run both engines at the same RPM, would not the boat perform as if the engines were matched? Would I be making a constant right turn? I know WOT would not be an option due to the mismatch, but I haven't done a WOT run in several years. I'm guessing my throttles would be 'misaligned' due to the new engine having a different power curve but if all I have to do is juggle the sticks, its only for one season.


Do you think this is a doable plan or should I just put in a 260 and move on?
Ultimately, after the second engine, I'd reprop with four blade stainless and more pitch to take full advantage of the increased power.

This is as much a thought experiment at this time as it is a plan so I'm open to any and all suggestions/comments. I'd rather hash it out here during winter than to throw money away in the spring.

I've been there......trying to decide how to repower my boat a year ago.

I think your best bet is what I did to my boat.
Replace your long blocks with brand new GM Marine long blocks.
Recondition and/or replace everything else. Things like brackets and pulleys can be bead blasted primed and painted to perfection. You'll end up with new power for a fraction of the cost.
You really have to consider what's worth doing to a 1989 30' Sea Ray...?
I mean diesel power would be fantastic but....impractical. Refreshing what was there when it was new plus maybe, saving some funds for the unknown or upgrades like new drives, canvas, recovering seating or just lots of fuel is the way to go.

 

[h_gerry]

I had the same dilemma on my old boat, a 1989 280 Sundancer with 5.7s (260 hp) with Alpha I drives. I had an engine fail, so working with my marina at the time (Mercruiser dealer) we replaced the bad engine with a Remanufactured engine directly from Mercruiser. It was the 5.7 TKS. Direct bolt in for the old motor. The marina guys told me that they think the engine was actually a NEW motor that Mercruiser relabeled as a remanufactured engine because the production run that year was not used up for new motor sales (this was about 2010-2011). The following year, we replaced the second engine. The 5.7 TKS we bought the year before was no longer available.We still went remanufactured route and got what they now called the “357” motor.The 5.7TKS was a 2 barrel carb while the 357 was a 4 barrel with a 357 cu in displacement and higher HP rating than the TKS engine.If memory serves me correctly, we paid about $6,500-$7,500 for each motor installed.We did change the pitch on the prop for the 357 motor (can’t remember specifics).Other than having to watch the throttles and adjust each motor a little differently, the boat ran great.Our plan was to keep the boat for another 5 years, until Hurricane Sandy changed that idea. We loved the boat and wanted to keep her around for a while, so we made the investment in the motors. After the repower, the boat ran great. She had a good top end and handled well. Aside from the throttles not being in the same position while on plane, I could not tell that I had “different” motors on each side.

My suggestion, look into the repower options available directly from Mercruiser. You may be surprised at the deals available.

 

[fatcatone549]

I have the same motor 125 hrs. on it now ,installed 2011 think I have bad valve guides ,smoke at idle .great motor but don,t like the smoke at idle.

 

[SCORPIO]

I should have updated this post a long time ago so better late than never.
I replaced just the port engine with a 5.7 Vortek 315HP complete engine from Michigan Motorz. I got the new Edlebrock carb, Delco Voyager ignition, new alternator, starter, coupler, flywheel, oil pan, valve covers, risers and manifolds, high rise intake manifold and a half FWC system as well as new motor mounts. I worked great with the old motor, even stayed in sync with the sticks up to 3500 rpms. I never did a WOT with it due to the mismatch. I ran it all of 2015 and most of 2016 when in early August of last summer the 1989 starboard engine let go and I did a three day turn and burn on a matching engine from Michigan Motorz. I now have a pair of new complete GM marine engines and they perform great! Anybody on the fence about the HP issue, I say go for it! I don't do hole shots and don't run WOT so the drives aren't seeing the full 315 HP anyway.