Mercruiser 3.0 reliability and overall maintenance?

[Ricksta7]

I am looking at purchasing a 2008 Searay sport 175 with a Mercruiser 3.0 (Alpha 1 leg). I've read some positive posts about this motor as they're economical with enough performace to cruise at 75kmh no problem. However I am a little sceptical as this is my first inboard. Some say as long as they're maintained and serviced then there won't be an issue. Others say the manifolds need replacing often which is costly. Also the legs aren't that great? I am confused and don't know what to buy. I want something with good performance however economical and as less cost to maintain as possible. Who doesn't! Should I stick to looking for an outboard or is this motor going to serve me well? Thanks all

 

[Ricksta7]

I am looking at purchasing a 2008 Searay sport 175 with a Mercruiser 3.0 (Alpha 1 leg). I've read some positive posts about this motor as they're economical with enough performace to cruise at 75kmh no problem. However I am a little sceptical as this is my first inboard. Some say as long as they're maintained and serviced then there won't be an issue. Others say the manifolds need replacing often which is costly. Also the legs aren't that great? I am confused and don't know what to buy. I want something with good performance however economical and as less cost to maintain as possible. Who doesn't! Should I stick to looking for an outboard or is this motor going to serve me well? Thanks all

 

[Ricksta7]

I should mention it has 257 hours. Intake manifold replaced at 200. Serviced at 240. Apparently serviced every year before summer and flushed regularly with fluids topped up every few runs. Is this enough to substain a healthy and reliable motor for myself if I were to purchase this boat?

 

[Scott Danforth]

first, welcome aboard

second, any used boat is only as good as the maintenance it recieved

the 3.0 is the entry level motor. it wont do 75kph unless your towing it. WOT speed in a light hull may be in the 65kph range. cruise would be in the 45-50kph range.

the A1G2 outdrive is good for up to 300hp (5.7 V8's) not sure where you got the comment in post #1

if you want low cost of maintenance in a boat, get a row boat
if you want economy in a boat, get a row boat powered by slaves like the vikings did or add a sail.

the fact that the intake was replace at 200 hours tells me that something was amiss in the boats past. I personally would walk away from it. also, with only 257 hours, thats averaging less than 20 hours per year. If this is a salt water boat that was flushed regularly (after every use), the intake should have lasted longer. it most likely sat for a while with salt water in it.

 

[paulswagelock]

The 3.0 alpha combination is a great little boat motor. However, it will perform about the same as a 115 hp OB for comparison. If using in saltwater, it takes special attention to keep it running well. That motor is raw water cooled so if it is a saltwater boat, saltwater has been sitting in that motor on and off for 12 years. If the boat is in really nice shape, the motor should not scare you away. It is a cheap replacement worst case. However, if the boat is just average, move on and hold out for the right boat.

 

[Ricksta7]

first, welcome aboard

second, any used boat is only as good as the maintenance it recieved

the 3.0 is the entry level motor. it wont do 75kph unless your towing it. WOT speed in a light hull may be in the 65kph range. cruise would be in the 45-50kph range.

the A1G2 outdrive is good for up to 300hp (5.7 V8's) not sure where you got the comment in post #1

if you want low cost of maintenance in a boat, get a row boat
if you want economy in a boat, get a row boat powered by slaves like the vikings did or add a sail.

the fact that the intake was replace at 200 hours tells me that something was amiss in the boats past. I personally would walk away from it. also, with only 257 hours, thats averaging less than 20 hours per year. If this is a salt water boat that was flushed regularly (after every use), the intake should have lasted longer. it most likely sat for a while with salt water in it.

According to specs on the motor it says it would reach 75kph? And btw I have seen the WOT mentioned many times and is doing my head in. What is it?
Glad the outdrive is strong.
Haha yes I was expecting a responce like that about economy.
Tbh the manifold replacement seems to be quite popular on these motors from what I have seen from other sellers too coincidentally. I don't know why. Now that it's been replaced do you not think it would run ok?

 

[Ricksta7]

The 3.0 alpha combination is a great little boat motor. However, it will perform about the same as a 115 hp OB for comparison. If using in saltwater, it takes special attention to keep it running well. That motor is raw water cooled so if it is a saltwater boat, saltwater has been sitting in that motor on and off for 12 years. If the boat is in really nice shape, the motor should not scare you away. It is a cheap replacement worst case. However, if the boat is just average, move on and hold out for the right boat.

The boat is immaculate and been well looked after. I can tell that. If running in saltwater and been flushed thoroighly after every use would this be a concern still? What would a replacement motor cost? $AUD. Hopefully I don't end up down that track.

 

[Rick Stephens]

130 Horsepower 3.0 liter motor and outdrive are not a 75 MPH setup. Not in your standard plastic n glass 17.5 foot long V hull boat anyway. At best high 50's, maybe low 60's in a really light weight configuration. Just like a similar sized outboard in similar size and weight hulls.. That said, the 3.0L Chevy motor is a great reliable motor when taken care of.

@achris is probably the best source for guestimates on replacement costs in Oz.

 

[Cortes100]

I had the exact boat, purchased brand new in 2009. used it for 8 years before going to a bigger boat. never gave me a lick of trouble. When I sold, it still looked like new. Always stored inside when not on the water.
The 3.0L is a great fit for this size boat. By myself it would top out at 42 mph. 2-4 adults was good performance. Pulled 2 tubes no problem and slalom skier no problem. Cruising at the 3000-3500 range it would sip fuel, we had some long days and never burned a full tank of gas, (80L).
Over the years, all I did was the regular maintenance, oil change, etc. Very easy access to the engine bay, so service was simple, even winterizing was easy. Replaced the raw water impellor only "just because" at the 5-6 year mark and it still looked fine. We boat in fresh water lakes.
Condition is a big thing on an older unit, so just start inspecting things under the surface. Wood is hard to find on this build.
Anyways, check it over, test drive, and see how it feels.

 

[bruceb58]

130 Horsepower 3.0 liter motor and outdrive are not a 75 MPH setup.

He said 75 KPH...46 MPH. It might do that.

 

[QBhoy]

46 mph ain’t happening on most boats like this, but 40 yeah. Early 40’s with a perfect prop maybe.
As for reliable...I’m not sure there is a more proven reliable motor ever put in a boat...period. All things maintained as they should be....cheap to service and maintain. Likely the most numerous engine ever mated to an outdrive in the world.

 

[Rick Stephens]

He said 75 KPH...46 MPH. It might do that.

Woof. Is it too late for me to learn to read?

 

[Lou C]

I’d be curious about the intake replacement...isn’t the intake/exhaust all one piece on these? That could explain it; if used in salt water your be replacing the exhaust manifold at 5-7 years regardless of hrs used. These engines are extremely simple much simpler and cheaper to repair than any modern outboard. I wouldn’t be afraid of it. As long as the power output meets your needs.

 

[Ricksta7]

I’d be curious about the intake replacement...isn’t the intake/exhaust all one piece on these? That could explain it; if used in salt water your be replacing the exhaust manifold at 5-7 years regardless of hrs used. These engines are extremely simple much simpler and cheaper to repair than any modern outboard. I wouldn’t be afraid of it. As long as the power output meets your needs.

Should I be worried about the replacement of the manifold or is this just done as a maintenance thing cos of corrosion?

 

[Ricksta7]

46 mph ain’t happening on most boats like this, but 40 yeah. Early 40’s with a perfect prop maybe.
As for reliable...I’m not sure there is a more proven reliable motor ever put in a boat...period. All things maintained as they should be....cheap to service and maintain. Likely the most numerous engine ever mated to an outdrive in the world.

The prop is a solas 14 1/8 x 19

 

[Rick Stephens]

Should I be worried about the replacement of the manifold or is this just done as a maintenance thing cos of corrosion?

If run in salt water you will need to inspect the manifold occasionally. Two things happen, first is scale starts blocking the cooling passageways. Second is the walls get thinner and you can induce a leak, especially at the riser joint. There are some pictures around the forum of what that looks like.

There are those who will give you a time frame to replace manifold when run in salt. I don't run in salt except maybe once a decade and my manifolds and risers are still like new and 30 years old. Reality rules here. Either assume a time frame or disassemble and replace on some sort of timely basis.

 

[Ricksta7]

If run in salt water you will need to inspect the manifold occasionally. Two things happen, first is scale starts blocking the cooling passageways. Second is the walls get thinner and you can induce a leak, especially at the riser joint. There are some pictures around the forum of what that looks like.

There are those who will give you a time frame to replace manifold when run in salt. I don't run in salt except maybe once a decade and my manifolds and risers are still like new and 30 years old. Reality rules here. Either assume a time frame or disassemble and replace on some sort of timely basis.

Where would I find the pictures of this? He reckons it will not have to be replaced for another 150 hours.

 

[Lou C]

I’ve had 20 years experience in salt. And if you go beyond 5-7 seasons you are taking a chance. My engine’s on its 4th exhaust system including the one it came with. It was used in fresh before I got it. First you get partial clogging and then you may get leaks between the manifold & elbow. 2 warnings are gradually increasing engine temp and rust stains from the joint between the manifold and elbow. If you check your spark plugs they may have an orange cast on the center electrode insulator; that’s a sign of water intrusion. Just part of boating in salt.

 

[QBhoy]

The prop is a solas 14 1/8 x 19

Won’t be doing 46 mph genuine gps then.

 

[Lou C]

Here's what an OMC Batwing V6 manifold looks like vs new after 5.5 seasons in salt. One outlet is totally plugged. These could be cleaned out and re-used but they were on borrowed time.