question for all you 3.0L 4-cyl merc owners

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the 130hp or 135hp mercruiser 4 cylinder 3.0L engine, I have one in a 19' bayliner. It's a 2002. At idle the motor sounds like a diesel, like it's really noisy valvetrain. Is this normal for this particular motor?

Reason I ask is I purchased the boat as a salvage last year, everything motor-wise was perfect, just a busted windshield seats. I put about 10 hours on it skiing last year @ 4000 rpms, on the

factory 25-40 oil I'm assuming. Did oil analysis, see below. Engine ran great last year. Put fresh 10w30 oil in it for winter storage, ran it for less than one hour this season then changed oil to redline 10w40. Oil is crystal clear on dipstick now and engine runs great. I plan on doing oil analysis end of this season or at 50hr mark.

So, if the motor isn't supposed to sound like it's been and it's not an internal engine problem nor an oil related problem, what might it be? Timing?

On a side note, the motor stumbles on acceleration all the time from 2000-3000 rpms. And when crusing at 3000-3200 the motor hunts a little- won't stay at a constant rpm. I'm 99% certain it's carburetor related and I've found some stuff on bulletin boards claiming fuel left in carb during boat delivery causing the carb power valve to stick or go bad, or the accelerator pump needs to be adjusted/changed/fixed. Anybody have any experience with this? It's a 2002 Mercruiser 3.0L 4-cyl Alpha1 sterndrive, 135hp.
Thanks.


> Oil Brand/Wt. Mercruiser 25w-40
> Type Equipment: Mercury marine gasoline engine Miles/Hours on Oil: 10
> Total Miles/Hours: 10
> Results Comment
> (ppm/%) (blank = normal)
> Wear
> Copper 20 new break in wear
> Iron 88 combo of break-in wear/intentional damage
from contamination
> Chromium 1 Normal
> Lead 20 break-in wear
> Aluminum 9
> Silicon 152 combo same as Iron, should be below 75ppm
> Tin 33 combo as above
>
> Additives
> Molybdenum 12 ring wear from dirt
> Sodium 107 additive
> Magnesium 710 additive and possible case wear,confirm
magnesium's use in the engine,if not then it is a critical AW/FM additive
> Zinc 900 additive, must find a oil that has a high
level of Zinc or other similar adds
> Potassium 0 Normal
> Phosphorus 784 Normal
> Calcium 474 very low value for acid neutralization
>
> Physical Properties
> Water negative
> Fuel negative
> Antifreeze negative
> Soot 0 NO solids, very good
> Oxidation 29 14.5% good
> Nitration 53 26.5% good
> Sulfur 38 good,normal
> TBN 11 good
> vis@100 C 11.5 30w instead of 40w.
>
 
I think your OK. On mine, '96 3.0LX, it does the same thing. I believe the 3.0 is an older engine block that Chevy used on their Nova line, a LONG time ago. They also don't have hydraulic lifters or roller lifters, just your standard pushrod on lifters and you will get some tapping sounds, not matter what kind of oil you use. But, from my experience and from others, the 3.0 is the workhorse engine for Mercruiser. They sell more 3.0's than the V6 and V8's. They are pretty reliable, just not a lot of upgrade options, but like your going to "soup" up your 4 banger???? If it's strictly valvetrain noise your hearing, you'll be OK.
Looking at the analysis, was suprized at the level of moly, 12? That's almost non-existant. I'd drop the oil and filter. Pennz. Long Life 15W-40 is good, lot's of additives holds up good when looking at UOA. I'm using Pennz. straight wt. 40, but I'm in Oklahoma, water temperatures here are pretty warm. Also using AC Delco long filter, holds more oil and works rather well and easy to grab when replacing with a new one. Make sure your outdrive is full of fluid and replace at the end of the season and then lube all the grease zerts. There are quite a few of them on this drive/engine set up.
Carb. Yes, there are a few TB on carb. issues for this engine. You basically have either Rochester or Mercruiser carb. I believe your year it's the Mercruiser carb. Main problem is that they are too rich. Either learn to feather the throttle at certain RPM's, get used to it or get a re-build kit.

[ July 21, 2003, 09:23 AM: Message edited by: Schmoe ]
 
thanks for the help. Since you said the lifters are solid not hydraulic, everything makes sense now and I feel better.

On the oil, that was the first oil change ever for that engine. I purchased the boat after as a salvage from being damaged cosmetically. To my knowledge it was only in the water less than a month before I took possession, and I ran it about 10 hours on that original oil before winterizing it and doing the oil analysis. I'll post the results of oil analysis of the redline at the end of this season, will probably be late October or november when that happens though. Had good analysis on redline 10w40 in my 351w in the other boat last year, hope it does as well in the 3L.
 
how about checking the valve lash ,Get a service manual first,check the ignition timing,and run some kind of feul system cleaner,and check the feul filter .
 
Wow
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going from a 3.0 to a Ford 351 Windsor must be a big difference and probably even a bigger let down. BUT, I bet you don't mind passing the gas pump by with that 3.0 as you would the 351. Everythings a trade off at some point in time. Sounds like you probably got a pretty good deal. I used to have a 21 footer with a 454 bravo drive in it. Yeah, it would do about 75, but I got tired of always working on it and it's not like everybody in the family wanted to go 75. Guess I out grew it and got a 18 foot 3.0 and must say I don't miss the speed and work at all!!!! Been a good boat and love it. Got an extra 5 mph out of it when I switched from a 3 blade 19 pitch aluminum to a 4 blade 23 pitch composite. With that low of hours on it, it should probably out last you
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