First cruise of 2011; great, but.... - Maxum Boat Owners Club

iceman · 02-07-2011, 04:19 AM

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

ed & inge · 02-07-2011, 07:00 AM

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

ss3964spd · 02-07-2011, 01:53 PM

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

Bella Sera 3300SCR · 02-07-2011, 02:31 PM

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

iceman · 02-07-2011, 08:33 PM

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.

ss3964spd · 02-07-2011, 09:21 PM

Quote:

Originally Posted by iceman

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

iceman · 02-13-2011, 12:42 AM

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.

seapuppy · 02-13-2011, 01:08 AM

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

Horizon · 02-13-2011, 10:55 AM

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.

iceman · 02-13-2011, 02:37 PM

Horizon: The engine is actually raw water-cooled. If there was water leaking into a cylinder, wouldn't it have failed the compression test?

iceman · 02-13-2011, 02:41 PM

Also I should mention, yesterday testing the boat out of the water I saw alot of white smoke when the engine was a higher rpm. I didn't see this with the boat in the water because there is less smoke after it warms up, and at 20 knots the smoke must dissipate alot faster.

seapuppy · 02-13-2011, 03:14 PM

if there were any water leaking into a cylinder, the spark plugs would be steam cleaned...quite litereally...

SP

ss3964spd · 02-13-2011, 07:52 PM

Interesting, Tom.

Good news is the compression test has all but ruled out a crack in a cylinder, combustion chamber, or head gasket. And the black plugs seem to suggest there's no water getting into any of the cylinders.

Regarding black plugs and fuel consumption; I believe there is a fuel pressure regulator on that engine, and it operates on vacuum. I've read that the reg's very frequently go bad (the diaphram inside develops a leak which allows gas to be drawn into the intake manifold) making the mixture very rich. In a car the rich condition is picked up by the o2 sensor(s) and the computer will throw a check engine light. Not so much on boats.

Are ya certain the smoke is white and not light gray?

Dan

Edit: And oh, I trust you checked the oil.......

iceman · 02-13-2011, 10:05 PM

Dan,

Yes there is a fuel pressure regulator and that and the rest of the fuel system is the next thing to focus on. My son didn't have the right test gear for that yesterday, because we suspected a gasket leak or crack.

The smoke could be light gray, I was assuming if it wasn't white it would be black, so I didn't look at the color that closely. What would gray smoke indicate?

Yes, both my son and I looked at the oil color and it seems normal.

ss3964spd · 02-14-2011, 01:37 PM

Tom,

The FPR might be as easy to check as removing the vacuum line from it and seeing if the inside of the vac line is wet with gas. If it is wet - bad FPR. Replace and go boating. If not wet, could still be the FPR but will need to actually test it to confirm one way or another.

Smoke color: White usually means water, light blue = oil, light gray to black means burning a very little to a very lot of excess gas.

I wouldn't expect to see black plugs (a picture of one would be great) on a fuel injected engine if everything is working properly. I'm pretty sure that, as far as electronic fuel injection systems go, ours are pretty simple since is it not monitoring the exhaust via O2 sensors and therefore the computer is just sticking to its program/map regardless of how much gas is getting into the cylinders. How old are the plugs? Did you verify they are the correct plugs for your application? Did they look "sooty"? Have you examined the spark arrestor to ensure it is not clogged? What shape are the dist cap and rotor in?

Dan

iceman · 02-15-2011, 04:22 PM

Dan,

I don't have good answers to your questions right now, but I'll know more today. My son is doing more diagnostics while I'm forced to sit here at work. He did some sort of simple test on the FPR last weekend, but it wasn't definitive. Anyway, I'm keeping my fingers crossed that it's something he can fix and I can stay clear of the shop for now.

Another thing he found was a small fuel leak out from the fuel pump outlet line. Not enough to cause 12 GPH to jump to 20 GPH, but something he wanted to fix. There was a strange "o-ring" on the fuel line... not round but more rectangular like a rubber band. The local auto parts store didn't have one and neither did West Marine. So it looks like something custom that Mercruiser uses...

Tom

deanries · 02-17-2011, 01:04 AM

Quote:

Originally Posted by iceman

Horizon: The engine is actually raw water-cooled. If there was water leaking into a cylinder, wouldn't it have failed the compression test?

As to the compression question, not necessarily. For some unknown reason if it is a head gasket leak it will still pass compression tests. Depend on where the break is. What about your crankcase oil, was it milky?, which indicates water intrusion and sign of a coolant system/head gasket problem.
Sorry to hear of all the woes, it's been said, "at least you've been out in 2011. Things are thawing here near St.Louis but the boat is still winterized and on jack stands. I've had my share of problems with the surge bakes and wheel cylinders. At least yours didn't lock up like mine did and overheat a wheel drum. Good luck in getting her back in ship shape. "Go Big or Go Home"
Dean (deanries)

iceman · 02-17-2011, 02:54 AM

Dean,

The oil looked normal, not milky. Work on the engine was delayed because the square cut o-ring that was on the fuel line is not a stock item anywhere in the SF bay area, apparently. So, can't start or crank engine for further diagnosis until it's replaced (it's on order). We should have it by Friday.

Yes I'm glad we got the early trip in. I hope we can fix things and be ready to go out again soon.

Tom

ss3964spd · 02-17-2011, 01:54 PM

Really depends on how bad it's leaking but yes, a static compression test will not always reveal a bad head gasket or small crack in a head or cylinder wall, but when the results of the compression test are considered along with the results of other tests (no water in oil, all plugs look the same) I believe I would be convinced to look elsewhere. If you have someone who knows how to do one you might consider a leak down test.

The huge increase in fuel burn, and the fact that all the plugs are black, indicate each cylinder is running rich so it's definately going to smoke. Think I'd be chasing that down first.

deanries · 02-18-2011, 01:52 AM

Tom,
Good to hear the oil was fine, saw that was already revealed after my post, sorry. As the above post states, the overly rich mixture will cause the plugs to be black and smoke from the exhaust. The fuel injection system is then suspect and the sensors it uses. These include any air intake sytem sensors. It needs to know how much air it is getting to control the amount of fuel. Not knowing the system I'd have to see the schematic to say more. Good luck to you and your son in getting to the bottom of the problem and back to Happy Boating!
"Go Big or Go Home"
Dean (deanries)