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Old 02-07-2011, 04:19 AM   #1
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Default First cruise of 2011; great, but....

Things fell into place for an overnight cruise to San Francisco this weekend, so I jumped at it. We (wife, son and me) had a great time, and I had a chance to test the new radar that I installed recently. The weather couldn't have been better, and it would have been a PERFECT weekend, but....

Leaving the dock Sat AM, I noticed alot of white smoke in the exhaust. I'd seen a small amount before at times, but this was alot. It continued as long as the engine was at idle RPM or slighly faster, but once I went on plane it was gone. Didn't see it when I came off plane an hour later though. One other strange thing during the trip out - the fuel burn rate, as measured by a Floscan, was much higher than usual. 18 to 20 gph when on plane, vs about 12 gph on prior trips. I thought the floscan was possibly off, but the gas fill I did after the trip confirmed the floscan numbers.

This morning I fired up the engine to leave SF and I see a black oil slick behind the boat! Now I know somethings wrong with the engine, but I don't know what. Other than these indicators (burn rate was high today also) the engine performed fine. So I guess I'll need to tow it to my local boat mechanic. Sure would like to have some idea what I'll be getting myself into though, if this sounds familiar to anyone here. The engine is a Mercruiser 5.0L EFI with only 80 hours on it.

If that wasn't enough, my trailer decided to get in the act. As I was backing it up to recover the boat, I heard loud clanking anytime I stopped. When I looked closely with wife driving, the surge brake was slamming forward even when going from very slow to stop. I checked the brake fluid and it was gone. Had to drop the trailer and get a bottle of fluid, and that got me home, but the reservoir was empty again once I got there. So I have leaks in that system, and more repair $$$ to look forward to. Not even sure how I'll tow the boat to the mechanic at this point.

Sorry for venting, it was a bittersweet weekend overall, and the upside is maybe I can get this all resolved before the heart of the boating season.

-Tom
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Old 02-07-2011, 07:00 AM   #2
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hai tom...

when a problem comes, they al come together, but look at it from the bright side......you had a trip, most of us are still waiting......

yesterday i was in the position to go to my boat since september (i have been operated 3 times in sept and okt) i payed the dealer 700 dollar for a service check and 600 dollars to store the boat because i was not in the position to take it home.........when i looked into the motor compartiment there was about 500 liter of water in it all the way to the front........the motor was in the water untill the v-belt......batteries were empty........so not happy again with this dealer......so i took the drain plug out, and it took about 15 minutes befor al the water was gone.......so i was pissed off yesterday and delivered him an e-mail that he is responsable for eventually damage.......

so you see.....your not alone......succes with finding the problem. greatz, ed
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Old 02-07-2011, 01:53 PM   #3
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Tom,

White smoke in the exhaust is the result of coolant getting into the cylinders. One of two things it can be; either the intake manifold gaskets are leaking or one or both cylinder head gaskets are leaking. I cannot quite remember but I think the Vortec engines are known for leaky intake manifold gaskets. If that's the prob there are updated gaskets to address the poor design of the originals. The poor mileage is explained because at least one cylinder is burning a certain amount of water instead of fuel.

Very first things to check: 1) Pull the dip stick to make sure the oil isn't chocolate milkshake colored. 2) Pull the spark plugs and compare them. Normally, all of them should look pretty much the same but if a cylinder is burning water then that plug will be noticably cleaner than the rest.

Regarding the oil slick. Ya sure it's from your boat? If so, really only two sources; 1) It isn't engine oil, it is outdrive oil. Check the OD oil level. 2) The engine is burning oil and the residue is exiting via the exhaust. Check the engine oil level. It is possible the engine is leaking oil and it is mixing with bilge water then getting pumped out by the bilge pump but not likely.

If all the break fluid is falling out that fast the leak point should be evident. Eyeball the entire system, including the back side of the tires.

Dan
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Old 02-07-2011, 02:31 PM   #4
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Tom,

Sorry to hear about the engine. One thing that is notorious with the 5.0 is that they crack in the lifter vally (under the intake manifold.) very easily. It is thought that the casting in the block is too thin to resist it especially at the rear of the vally. Ive seen it more than once in friends 305's. Anyhoo, the other suggestion of milky oil will confirm it. The trouble is that that with a lifter vally crack, you are looking at a a new or rebuild shortblock unless they can repair it with Irontite plugs from Martin Wells Co.

Good Luck Tom.

Bell Sera 3300SCR
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Old 02-07-2011, 08:33 PM   #5
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Ed, Sorry to hear about the water intrusion. I hope there is no long term effect. Thanks for commisserating with my situation though!

Dan, thanks for all the great input. I know enough about engines to be dangerous but I'm not a mechanic, so I thought there might be a cracked block, but I hadn't thought about it being a coolant leak. I will look at the oil tonight. I guess I understand the fuel consumption issue. If one cylinder is leaking water, the others have to burn more gas to get to a certain RPM?

At any rate, it sounds like this is going to be expensive.

Bella, thanks for your comments as well. This will help me speak more intelligently with the mechanic.
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Old 02-07-2011, 09:21 PM   #6
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Quote:
Originally Posted by iceman View Post
If one cylinder is leaking water, the others have to burn more gas to get to a certain RPM?
Yup.

You might also be able to diagnose the problem by doing a cooling system pressure test, as well as a cylinder compression test.

Dan
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Old 02-13-2011, 12:42 AM   #7
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Got a status update, as my son, a master auto mechanic, offered to take a look at the situation.

First, the brakes: 4 of 6 wheel cylinders were leaking. All 6 have been replaced and I'm back in business with that at least. Wish I could figure out why they seemed to fail at once. Actually they no doubt degraded over time, but the final failure was catastrophic. The wheel cylinders sit at the top of the hub assembly, below where the flush tube squirts, so they don't get flushed very well I guess.

We're not sure about the engine yet. All 8 plugs were black, and one didn't stand out from the others. Black seems to indicate the engine's running rich, which is consistent with the excessive fuel consumption. Compression checks on all cylinders were 175 to 185 psi, all within norms. So no cracked block, head or gaskets? Perhaps fuel control. Throttle position sensor and temp sensor checked out OK. Couldn't check other things like the MAP sensor or fuel pump yet.

Ideally we'd read the computer faults codes. My son didn't recognize the connector on top of the engine labelled "CAN Line", that looks like a computer port, so he couldnt' use his automotive device to read the codes. Anyone know if marine engines have a different fault code reader/interface than cars? This is a 2005/6 Mercruiser 5.0L EFI.
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Old 02-13-2011, 01:08 AM   #8
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wow...sounds like a crazy day.....glad you got the trailer working properly....that's one down...
as for the computer read out...yes..there is a different plug and software that a merc' tech will have along with the software to read it...it can download all of the codes and actually where the throttle is at any given time.....


thanks for keeping us updated...

SP
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Old 02-13-2011, 10:55 AM   #9
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Sorry to hear about the engine woes.
I am assuming you have fresh water cooling.

Some have suggested antifreeze getting in the combustion chambers (see ss3964spd comments)- one more place to look is the exhaust manifolds. A crack in the exhaust manifold or its block off gasket will result in antifreeze in your cylinder(s). When you start your boat it will show white smoke until the antifreeze is gone (also causes hydro-lock), then when the engine runs for a bit the white smoke is gone.

This has been suggested already- do a leak down test on the cooling system. Also check the cooling system level.
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Old 02-13-2011, 02:37 PM   #10
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Horizon: The engine is actually raw water-cooled. If there was water leaking into a cylinder, wouldn't it have failed the compression test?
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