3.0 liter Mercruiser engine noise?
 

I know it's not performance stuff but I'm sure someone here can help me.
I looked at a little Sea Ray today with a mate who just wants to putter around close to shore with his kids. Boat/engine is 2009 and we ran the engine on the hose. Started nicely but the engine sounded 'rattly', not as bad as a diesel sound but sort of similar. Didn't rev it beyond 2,000 rpm on the hose. Seller says it's all A1 and I've no reason to doubt him.

Couple of questions, are they a noisey little engine?
Would a good test run across the rev range highlight any issues?
Alpha one gearbox oil reservoir was low and he said the sensor that was beeping because the oil is low. What would you do, put a little oil in it first and then watch closely? (I didn't know they had a sensor!)

I just want to help out a good friend who knows even less than I do so any input will be very much appreciated.

Thanks,
RR

Hard to tell without being there to hear it but they are kind of noisey. 'Rattly' was a good description. Worked on one the other year in a pontoon. Luckily that was the only one. LOL.

I can say that since they are so wimpy, they are typically run hard most all the time.

My buddy has this engine in a 17 Rinker. It's relatively quiet when running. IIRC there was a guy on FB that had noise in a 3.0, I think he ended up installing new lifters.

I wouldn't mess with it. hard motor to get parts for, especially in thailand. you live in outboard country. I am sure center consoles with outboards are plentiful.

is it carb or MPI - yes I have to work on these to because people buy entry level boats as well with the 3.0 L engines in them. Carb and MPI. Yes Merc has made a 3.0 MPI for years..

If this is a TKS carb engine NOT MPI --- the carb does not have a choke - all Mercruiser black carb engines from 2003 / 2004 went to a TKS carb - its a 2 bbl carb with a solenoid on the back side again no choke. These things are noisy as hell when warming up. It takes a bare min of 5 mins to even 10 to 15 mins depending on air temp for the damn thing to deactivate the TKS solenoid. I really do not want to get into all the tech stuff about TKS carb. But believe it or not they can sound like a u - joint rattle noise until it fully warms . TKS = Mercruiser way to promote Turn Key Start. NO choke

here is what a Merc TKS carb is - they are very expensive thru Merc and really worthless. They 4 sure can become very problematic especially if one does not perform fuel maintenance.

https://www.marineengine.com/parts/i...08M0084193.jpg

I call it the straight 4 roar. They are a pretty rugged engine though

many of the parts to this GM engine come from mexico including the block They internally corrode from the inside out very easy. Even in lake waters. I would not own one nor want one. also a flat tappet engine so if the correct motor oils has not been used - watch out.

They can break starter bolts easily because of the harmonics from the engine at the 2000 - 2800 rpm ranges -- The starter needs the front bracket installed if they do not have them already. Merc and Volvo know this and offer a bracket kit plus correct starter bolt torque is required at all times and must be checked. 30 ft lbs

In the summer boating months - I see about 2 to 3 - 3.0 L Merc and Volvo s per week. They are not dependable engines. Even Volvo knew this and quit making the 3.0 L : back in 2010. Merc is dropping it as well. if they have not already. ---- prob left over stock if they have them.

We deal with these same engines in the forklift biz and yes they can be a bit noisy

The 3.0 is an industrial motor and been around a long time. Not much power but taken care of it will hold up a long time just as any other motor. There are thousands of them in all kinds of boats so I have never found finding parts an issue.

A test ride is always a good idea

After running the boat for the test ride, put it on the trailer and have the drive full down, then remove the drain plug just enough to see what the gear lube looks like. If it looks good then probably (if it is bought) remove the drive, drain and pressure / vacuum test it