Author Topic: Mercruiser 120 engine seems to be using oil? (Read 31598 times)

Jason · « **Reply #40 on:** October 18, 2014, 08:28:56 PM »

You can buy a reman from Michigan Motorz for $2K.

http://www.michiganmotorz.com/marine-engine-19681990-p-942.html

dorelse · « **Reply #41 on:** October 18, 2014, 08:33:11 PM »

I was gonna say, I think my 305 V8 was originally priced at $2200, and that was a complete rebuild & included carb rebuild, timing, etc, everything to make the engine so it was 'drop in' and run from a well-known reputable machine shop in town.

(It ended up being significantly cheaper due to an error on their part.)

buckz6319 · « **Reply #42 on:** October 19, 2014, 09:14:11 AM »

Quote from: Neutron68 on October 18, 2014, 11:43:40 AM

Going on the diagnosis of the evidence, it appears the engine is using/burning oil.
From the feedback I've received here and elsewhere, the symptoms are pointing to piston rings.Piston rings would be my first guess. Improper break in can lead to an early problem. Engines that sit idle for months (like a boat sitting all winter) are really prone to ring problems because the cylinders rust during the periods of non use, the walls get pitted and then the pits wear at the rings.Ring problems will be much worse at high RPMs.
The guy in Lake Mills, IA who sold me the boat either had no idea the engine was in such shape, or he was very good at acting ignorant!every one knows the condition of what they are selling, with a few exceptions of course.

Based on all that, I'm considering having the engine taken out and have a ring job done.before you go through all that i would get a price on a cylinder compression leak down test per each cylinder, done by a reputable mechanic, and have her/him present the numbers to you, and explain what they mean, then go from there, I'm not totally sure a re-ring job will solve what ever issue is going on, cylinders may need punched out, new rings ect, but remember I'm no expert Master Tech, just throwing things out there for ya to consider

I got an quickie estimate from an engine guy that Dan Luke knows. This guy said if he got the engine, he would redo/replace all old and worn parts, not just the piston rings, while he had it apart. His estimate...$3000.IMO I feel like you would come out better by purchasing a New Long block engine with warranty,( they have all new parts, crank, bearings, connecting rods, pistons, rings, front and rear main seals, oil pan, head, valves, spring, caps, push rods, rockers, rocker cover ect, I may have missed something here, but I think you get the picture...and have the Mechanic transfer all the goodies from the old engine, to the new engine, and whatever appears to be bad, or going bad, replace that with a new part/ buy what you need and go from there

Does $3000 sound like a reasonable price for the redo of a 1978 engine, when you end up with a known-good engine that should run well for 10+ years?sounds high IMO

In the fall, used boats seem to have their lowest value. I'm starting to see newer boats in very similar Mercruiser I/O configurations for $5000.If your happy with the boat keep it, and do what ya got to do
http://www.boattrader.com/listing/1991-Raven-170-Open-Bow-102294345
http://www.boattrader.com/listing/1991-Four-Winns-190-Freedom-102337130?datalink

I hate the idea of throwing away all the $$ and work I've put into this boat, but a 1991 boat for $5000 has me thinking hard about spending $3000 on an engine rebuild in a 1978 boat.this will be a tough decision, that only you can make
Is it throwing good money after bad?...

Eric

good luck Eric...I hope you find the way in which to go...

Neutron68 · « **Reply #43 on:** October 20, 2014, 10:20:20 AM »

I thank you all for the input. It is helping me put the choices into perspective.

I like the idea of having a 120 engine rather than a 140. I've read that the Mercruiser 120 has lower fuel use than other I/O engines. The 120 has plenty of power and I like the lower gasoline consumption vs. a 140, for example.

I agree - I think I need to get an experienced mechanic to run the engine in their shop, perform some tests and try to make a diagnosis without tearing the engine apart. That is the only way I can see to keep the costs down - only fix what needs fixing, rather than redo everything?

I suspect that if I bought a gone-through $2000 engine from someplace like Michigan Motorz, I would have to pay another $1000 for a local marine mechanic to swap out the current engine, put the rebuilt engine in and make sure the engine and drive work together properly. If that is true, I'm right back at the $3000 mark.

New infomation:
In August, I added some Sea Foam to the engine oil, with the thought of cleaning out carbon deposits.
I winterized the boat yesterday. I changed the engine oil and oil filter, as part of the process. One of my lake neighbors actually tried to talk me out of changing the oil!?

1. oil on dipstick was a little hazy but not dirty
2. oil in the oil filter was black
3. oil in the oil pan was black
4. the old oil has a slight gasoline smell
5. there were some black, oily deposits around the edge of the water puddle on the driveway after the running the engine for about 15 minutes

I'm not sure if these details tell us anything?

Did the SeaFoam actually clean out carbon deposits, which ended up in the oil, and the SeaFoam-thinned oil ended up in the exhaust?

Eric

CVX Fever · « **Reply #44 on:** October 20, 2014, 12:22:22 PM »

Will the 140 really use that much more fuel than the 120? I'd think that at planing speeds the 120 isn't one bit more efficient than the 140, so fuel consumption will be equal. Is there is a substantial weight savings over the 140. The 120 will use less gas at displacement speeds but then your hardly burning any fuel anyways.

With my CVX18 i'm pulling the 305 and installing a 350. The bigger motor doesn't weigh an oz more and offers better torque which means I can turn a taller pitch prop. So in my case the larger motor will actually burn less fuel at most speeds. Either way it takes the same amount of horsepower to push the boat through the water regardless of the engine size and the 305 won't do it anymore efficiently than the 350.

Your boat so do what you feel comfortable with. I would think the fuel comsumption would be so close between the 2 engines that it becomes a non-issue. I could be wrong. I am all the time, just ask my wife and kids!......LOL

75starflight · « **Reply #45 on:** October 20, 2014, 01:09:18 PM »

From personal experience in the same hull I have run both the 120 and currently running the 140 and have not noticed any change in fuel usage. I cruise on average around 3000 - 3500 rpm and for being on the lake for 2 hours I maybe use a little over 6 gallons out of my 18 gallon tank.

Neutron68 · « **Reply #46 on:** October 20, 2014, 03:43:58 PM »

Is the power difference noticeable between the 120 and 140?

75starflight · « **Reply #47 on:** October 20, 2014, 03:50:58 PM »

Quote from: Neutron68 on October 20, 2014, 03:43:58 PM

Is the power difference noticeable between the 120 and 140?

In my book yes. I have good power through my rpm range, and even gained around 5mph on my top end.

Neutron68 · « **Reply #48 on:** October 20, 2014, 04:08:39 PM »

OK. Extra power on the top end makes sense, because the 140 is rated with a faster top RPM than the 120.
See 1978 spec page.

75starflight · « **Reply #49 on:** October 20, 2014, 04:39:01 PM »

Quote from: Neutron68 on October 20, 2014, 04:08:39 PM

OK. Extra power on the top end makes sense, because the 140 is rated with a faster top RPM than the 120.
See 1978 spec page.

I hate to rain on your spec sheets data, but, my 120 with the 19p prop would turn 5200rpm no problems. i dialed it down with a 21p stainless to 4800rpm and had an idle of around 400rpm. I think those specs are set on too much degree before tdc. I had my 140 set to the 6 degree before tdc by the book and could only hit 4600rpm and it would idle at 700rpm(which i did not like) and i could tell it had more in it even at WOT. when i put a new camshaft in it i reset the timing spec to i believe 2 degrees after tdc (i have not checked this yet), and it now seems to have a better rpm range than i had with the previous timing set at 6 degrees. it now idles at 400rpm like my 120 used to and just running it on the hose in my back yard the engine just has a totally different sound now. I need to do a little fine tuning on my timing before i winterize it but I will not be putting it back at the suggested timing spec in the IT manual. to me it just seems to curb the engines ability to produce power.

Neutron68 · « **Reply #50 on:** October 20, 2014, 05:11:16 PM »

It's not my spec sheet, it's Mercruiser's!

Why would they put these numbers in their spec sheet if they were so different from the real world?
So they can underpromise and overdeliver (UPOD)?

75starflight · « **Reply #51 on:** October 20, 2014, 05:12:35 PM »

Quote from: Neutron68 on October 20, 2014, 05:11:16 PM

It's not my spec sheet, it's Mercruiser's!

Why would they put these numbers in their spec sheet if they were so different from the real world?
So they can underpromise and overdeliver (UPOD)?

my guess, safety reasons.

Rich_V174SS · « **Reply #52 on:** October 20, 2014, 05:26:09 PM »

I think they're just being conservative. I ran my 120 up to 4600 rpm turning a 21p prop.

Neutron68 · « **Reply #53 on:** October 20, 2014, 05:34:03 PM »

Any thoughts on the info I got during the oil change?

Quote

New information:
In August, I added some Sea Foam to the engine oil, with the thought of cleaning out carbon deposits.
I winterized the boat yesterday. I changed the engine oil and oil filter, as part of the process. One of my lake neighbors actually tried to talk me out of changing the oil!?

1. oil on dipstick was a little hazy but not dirty
2. oil in the oil filter was black
3. oil in the oil pan was black
4. the old oil has a slight gasoline smell
5. there were some black, oily deposits around the edge of the water puddle on the driveway after the running the engine for about 15 minutes

I'm not sure if these details tell us anything?

Did the SeaFoam actually clean out carbon deposits, which ended up in the oil, and the SeaFoam-thinned oil ended up in the exhaust?

buckz6319 · « **Reply #54 on:** October 20, 2014, 05:37:20 PM »

Quote from: Neutron68 on October 20, 2014, 10:20:20 AM

I thank you all for the input. It is helping me put the choices into perspective.

I like the idea of having a 120 engine rather than a 140. I've read that the Mercruiser 120 has lower fuel use than other I/O engines. The 120 has plenty of power and I like the lower gasoline consumption vs. a 140, for example.

I agree - I think I need to get an experienced mechanic to run the engine in their shop, perform some tests and try to make a diagnosis without tearing the engine apart. That is the only way I can see to keep the costs down - only fix what needs fixing, rather than redo everything?

I suspect that if I bought a gone-through $2000 engine from someplace like Michigan Motorz,Eric I believe those engines are new, not rebuilt, someone correct me if I'm wrong I would have to pay another $1000 for a local marine mechanic to swap out the current engine, put the rebuilt engine in and make sure the engine and drive work together properly. If that is true, I'm right back at the $3000 mark.

New infomation:
In August, I added some Sea Foam to the engine oil, with the thought of cleaning out carbon deposits.
I winterized the boat yesterday. I changed the engine oil and oil filter, as part of the process. One of my lake neighbors actually tried to talk me out of changing the oil!?

1. oil on dipstick was a little hazy but not dirty
2. oil in the oil filter was black
3. oil in the oil pan was black
4. the old oil has a slight gasoline smell
5. there were some black, oily deposits around the edge of the water puddle on the driveway after the running the engine for about 15 minutes

I'm not sure if these details tell us anything?

Did the SeaFoam actually clean out carbon deposits, which ended up in the oil, and the SeaFoam-thinned oil ended up in the exhaust?

Eric

Neutron68 · « **Reply #55 on:** October 20, 2014, 06:11:08 PM »

These?:
http://www.michiganmotorz.com/base-marine-engine-19672014-replacement-p-67.html

Quote

New GM base marine engine (standard rotation)
3.0L base engine includes: engine block, cylinder head, valve cover, oil pan, circulation pump, Delco Voyager distributor (includes electronic distributor, coil with bracket, coil-to-distributor wire and timing shunt - spark plug wires are NOT included), harmonic balancer, flat tappet cam, 14"" flywheel, spark plugs, corrosion-resistant, black urethane paint and all internal parts.
One-piece rear main seal (also known as full rear main seal)
Mechanical fuel pump pad
Rated at 140 hp @ 4800 / 177 LB FT @ 2800 with 2-barrel carburetor. (actual power levels may vary depending on OEM calibration and application)
Direct replacement for 1990-2014, 3.0L OMC, Volvo Penta, MerCruiser, etc.
Will work for pre-1990 2.5L & 3.0L applications with updated 12¾" flywheel and updated engine coupler.
Includes thermostat housing gasket and intake gasket.
Spark plug wires are NOT included.

One-Year (parts & labor) Written Warranty

buckz6319 · « **Reply #56 on:** October 20, 2014, 06:59:57 PM »

Quote from: Neutron68 on October 20, 2014, 06:11:08 PM

These?:
http://www.michiganmotorz.com/base-marine-engine-19672014-replacement-p-67.html

Quote
New GM base marine engine (standard rotation)
3.0L base engine includes: engine block, cylinder head, valve cover, oil pan, circulation pump, Delco Voyager distributor (includes electronic distributor, coil with bracket, coil-to-distributor wire and timing shunt - spark plug wires are NOT included), harmonic balancer, flat tappet cam, 14"" flywheel, spark plugs, corrosion-resistant, black urethane paint and all internal parts.
One-piece rear main seal (also known as full rear main seal)
Mechanical fuel pump pad
Rated at 140 hp @ 4800 / 177 LB FT @ 2800 with 2-barrel carburetor. (actual power levels may vary depending on OEM calibration and application)
Direct replacement for 1990-2014, 3.0L OMC, Volvo Penta, MerCruiser, etc.
Will work for pre-1990 2.5L & 3.0L applications with updated 12¾" flywheel and updated engine coupler.
Includes thermostat housing gasket and intake gasket.
Spark plug wires are NOT included.

One-Year (parts & labor) Written Warranty

Neutron68 · « **Reply #57 on:** October 21, 2014, 11:00:14 AM »

I called an engine guy out in New Germany, last night.
He gave me a firm quote for resolution of my oil usage problems.

Options:
1. Remove, redo and reinstall my current 120 engine: $3975, for his labor and parts.
2. Install one of the new $2300 Michigan Motorz "basic block" 140 engines: $2500, for his labor and parts not included (starter, alternator, carburetor, exhaust manifold, exhaust elbow, fuel pump, belts, hoses, thermostat housing, thermostat) with $2300 "basic block" (total $4800)
3. Install a used, working 140 engine he has on hand (starter replaced, carb rebuilt): $1500, parts and labor

This is frustrating. I know there is a problem, but don't know exactly what it is. From what I gather, the engine must be taken apart to find out what is wrong, and fix it. Labor costs money, so it would cost a fair amount just to explore the engine, learn exactly what is wrong and THEN more money to fix it.
I need a solution that will stop the oil usage, give me 10+ years of trouble-free operation, without spending $4000 or more.

Jason · « **Reply #58 on:** October 21, 2014, 12:15:03 PM »

Well, you could install motor yourself. That's the easy part.

Or just keep adding oil and run her till she pops.

I am in the same boat as you. well, not literally! My 140 has been making noises for a while. Then managed to overheat it pretty good a month ago and probably warped the head. I am leaning towards a Michigan Motorz engine but install myself. I don't ever plan to cell my CV16SS so a engine i can run for 30 years without worries is my main concern.

75starflight · « **Reply #59 on:** October 21, 2014, 01:18:25 PM »

I would have gone with the michigan motorz engine for Phoenix Rising if it wouldn't have been for the small port head that comes on them and it gave me an excuse to build my first engine.