Is Volvo Penta 3L a good engine?

[boatdude100]

I'm sorry I know more details are probably required, but I'm looking at possibly buying a boat and that's all the info I have until I arrive and have to make a decision on the spot. Because that's the way it goes more often than not. The boat is made in 2000. Thanks!

 

[alldodge]

Like all motors, its only good if it has been taken care of. The 3L is a GM industrial motor and can last for many years. Same goes for most all motors

 

[Lou C]

Like any inboard/outboard power plant they require regular maintenance, especially making sure you don't have leaks from the water-cooled exhaust system into the cylinders, that is a major cause of trouble in inboard gas engines. The 3.0 in particular is prone to blown head gaskets, so check for water in the oil and low compression.

 

[Scott Danforth]

make sure to read this: https://forums.iboats.com/threads/f...help-buying-a-boat-a-buyers-checklist.612841/

the 3.0 motors are entry level motors for I/O's. being a 23 year old boat (yes, we are entering M/Y 2023 for boats and cars). the motor is only as good as its maintenance. the motors are 1950's technology industrial motors that was refreshed in 1990 for easier manufacturing processes.

the good is volvo penta motors have the raw water pump mounted to the front of the motor and not in the drive, so hopefully the prior owner has done his annual impeller inspection

however has the prior owner done his yearly drive maintenence and pulled the drive every year to inspect the alignment, the gimbal bearing and the u-joints and replace the bellows every few years?

with the question "is it good", we can not answer as we are not the ones inspecting it. how good the motor is now 23 years after it was manufactured comes down to maintenance.

Check the compression. a new motor is 150 psi in all cylinders. a worn motor should be well above 130 psi in all cylinders, any cylinder lower than 100 psi is essentially dead. any cylinder above 150 psi has water or oil in the cylinder

check the block under the manifold for signs of cracks. this is where the block cracks if there was improper winterization.

 

[QBhoy]

Like any inboard/outboard power plant they require regular maintenance, especially making sure you don't have leaks from the water-cooled exhaust system into the cylinders, that is a major cause of trouble in inboard gas engines. The 3.0 in particular is prone to blown head gaskets, so check for water in the oil and low compression.

Wasn’t aware of this Lou. Always considered the 3.0 GM as just about thee most reliable and bombproof marine engine ever used. I know they are certainly the most numerous fitted engine ever installed in a boat ever. Arguably the most successful too.
No doubt they are a little unrefined and harsh to the ear…and the boat that usually has them may have a preferred upgrade 4.3 option that’s better most times…but it would be a brave man that argues they aren’t as reliable as it gets, with minimal maintenance. Of all the 3.0 GM engines I’ve known and surrounded by anywhere I look…not sure I’ve known any to be prone to cylinder head issues generally…outside an overheated example that wasn’t any inherent fault of the engine, rather than the owner

 

[Lou C]

I’ve seen numerous cases on this and other forums where the 3.0 blew a head gasket which seemed to be detonation related. They seem to be more sensitive to too much spark advance or low octane fuel. As an aside I have always used at least 89 octane in our boat with the 4.3 and the gas docks I use sell only 93 octane fuel.

 

[Scott06]

I’ve seen numerous cases on this and other forums where the 3.0 blew a head gasket which seemed to be detonation related. They seem to be more sensitive to too much spark advance or low octane fuel. As an aside I have always used at least 89 octane in our boat with the 4.3 and the gas docks I use sell only 93 octane fuel.

Agreed seen these types of comments at one point merc reduced their initial timing on some, but overall the 3.0 is a reliable powerplant. Mine served me well for 20 years towing skiers and tubes.... really amazed me how well it lasted given how hard we used it. Many a day my kids, their friends, tubing very heavy into the throttle for an hour straight... still had 145 compression when I sold it...

 

[Lou C]

On the plus side they are very easy to take apart, like other GM marine engines, if you ever have to replace the head gasket and do a valve job.
To avoid problems make sure that:
The boat is propped correctly, if the engine does not reach max specified RPM it will cause very high combustion chamber temps and that is known to burn exhaust valves and can blow head gaskets
Make sure the timing and total timing advance is correct
Use proper mid range fuel, no matter what people tell you, as the engine accumulates a bit of carbon build up over time, the octane requirement of the engine increases over time. So if regular fuel was OK when new it may not be now. I'd use at least 89 octane if not 91 or 93 depending on what's available to you.
Maintain the exhaust system properly to keep water out of the cyls
Remember inboard/outboard power trains are high maintenance by design. There is an adapted auto engine, a transom mount and outdrive. Outboards are designed from the start to be in a boat.