Mercruiser 3.0

[PADDLES]

Good morning team, a mate of mine is looking at buying a second hand fun boat with a 3 litre mercruiser (he's looking at 2002 and newer). I know a little about it's V6/V8 cousins because I've got one, but nothing about these 4 cylinder ones.

Can anyone give me a few pointers on what goes wrong with them and what I should be keeping an eye out for when we go and have a look at it? He's going to get it inspected and fully serviced by a mercruiser guy but it'd be nice if we had a bit of a heads up on what to look out for.

[BM]

Good morning team, a mate of mine is looking at buying a second hand fun boat with a 3 litre mercruiser (he's looking at 2002 and newer). I know a little about it's V6/V8 cousins because I've got one, but nothing about these 4 cylinder ones.

Can anyone give me a few pointers on what goes wrong with them and what I should be keeping an eye out for when we go and have a look at it? He's going to get it inspected and fully serviced by a mercruiser guy but it'd be nice if we had a bit of a heads up on what to look out for.

Not a bad engine mate. An off the shelf Chev unit. I would be giving it a comp test. 10% variation is your tolerance. Check the engine oil colour. Check the oil colour in the leg. Fire it up and check the oil pressure and temp. Also check that the battery is charging. Volt gauge shoould be above 12.7V. Check it's shifting gears properly and with it in gear check that the prop runs true. (ie: propshaft ok). Check power trim operation and look for any ram leaks. Also check for excessive play in the transom assembly. Rock the drive gently side to side and if it's sloppy you have a tiller arm problem most likely.

To check this, have someone look at the tiller arm from inside the boat (where the steering cable attached) and note how much free play is there.

Also grab the lower leg and pull outwards (away from boat) as this will check the bottom mount pin of the gimbal assembly for wear.

You can check the gimbal bearing and uni shaft by turning full lock whilst the engine is running. Any problem will show up like a grumbling growl. Just like a front wheel drive car with shot uni's on its driveshaft.

Other than that just look in general for any signs of anything that simply looks not right.

Cheers

[PADDLES]

thank you sir, it's got an alpha leg on it like i've got at home so i'll check all the basics like you've outlined. is there any easy way of checking the manifold/riser for corrosion without major disassembly?

[BM]

Not really mate. The signature of a clogged/restricted exhaust elbow is that the engine will get to temp and after a few minutes (running under load) will gradually get hotter and hotter.

Cheers