2003 MerCruiser 4.3MPI Alpha I Gen II with an awful noise, need help identifying.

[120mmAPFSDS]

We've been trying to get this boat running after a failure to winterize two seasons ago. There were cracks but only in the water holding areas of the heads but they were JB welded and have since held. We got the fuel system primed and it started cranking like a champ once we cleared the bad gas from it and added some seafoam to clean it out. With the water muffs on, we let it idle for a while then revved it up to 3000 RPM when a burst at the bottom of the engine occurred, which brings us to where we're at now. Engine's making an awful noise and it's got some vibrations going on. Video attached should give you an idea.
Sound started after a burst of black smoke from the bottom of the motor came out smelling like burnt plastic/rubber. No more smoke since. We're at a loss for what it is.
Serial number is OM647700

 

[alldodge]

Sounds like something isn't getting oil.
Is the oil level correct?

Remove the drive and attach hose the the thermostat housing,

 

[120mmAPFSDS]

Sounds like something isn't getting oil.
Is the oil level correct?

Remove the drive and attach hose the the thermostat housing,

Last I checked the oil level is correct and the oil pressure gauge holds steady at 40.
What would attaching the hose to that do? Not familiar with this engine also. Are you referring to the outdrive with the propeller?

 

[alldodge]

The noise might be coming from the outdrive. If the drive is removed and the noise continues then we know its the motor and not the drive (engine coupler, U joints)

You can run the motor without water going in (hose attached to thermostat housing) but only for a brief, short time

 

[Bondo]

What would attaching the hose to that do? Not familiar with this engine also. Are you referring to the outdrive with the propeller?

Ayuh,....... Welcome Aboard,...... As AD says, pull the drive, as it's splined to the crankshaft, 'n turns with the motor,.....

Hookin' yer garden hose to the "In" port on the t-stat housin' supplies water to the motor, so you can test run it,.....

When you rev'ed it up,... was the outdrive, Up, or Down,..??

 

[Scott06]

Agreed check these drive items mentioned above Trim and remove.... would also remove the accessory belt on front of engine not sure but looked like water pump pully wasn't turning at same speed constantly if frozen could be as simple as busted impeller in block circulation pump grinding. Run it briefly wth drive belt removed, if sound goes away check the water pump, alternator, ps pump for rougness.

 

[120mmAPFSDS]

Ayuh,....... Welcome Aboard,...... As AD says, pull the drive, as it's splined to the crankshaft, 'n turns with the motor,.....

Hookin' yer garden hose to the "In" port on the t-stat housin' supplies water to the motor, so you can test run it,.....

When you rev'ed it up,... was the outdrive, Up, or Down,..??

Trimmed all the way up

 

[alldodge]

Trimmed all the way up

Bondo has it
That is your U joints destroying them selves

Never run the motor with the drive up, you might have more work to do

 

[Bondo]

Ayuh,..... Yer Not supposed to do that,...... it's recommended that with the drive down you limit the rpms to 'bout 1500 on the hose,.....

With the drive All the way up, dead idle is too fast,...... the u-joints bind, Terribly at that radical angle,......

That rips up the u-joints, the yokes, 'n possibly the bellows, as well as potentially the transom housin',.....

Go pull yer outdrive, 'n retest the motor,......

 

[Bt Doctur]

atleast pull the drive to inspect everything

 

[120mmAPFSDS]

Thanks to all of you for your responses. I can't believe it didn't hit us to not trim the motor down, we feel like fools.
We will take the outdrive out ASAP and will report back with likely more questions, but with the holiday this weekend we may not have time until next weekend. I hope you all will still be willing to help then :nevreness:.

 

[Scott06]

The black smoke and burning may have been the coupler if the ujoints locked up ? Only thing that would make a burning smell would be the rubber from the coupler. When you pull the drive you can look through the gimbal bearing and see what the coupler looks like ... look for bits of rubber

 

[tpenfield]

Thanks to all of you for your responses. I can't believe it didn't hit us to not trim the motor down, we feel like fools.
We will take the outdrive out ASAP and will report back with likely more questions, but with the holiday this weekend we may not have time until next weekend. I hope you all will still be willing to help then :nevreness:.

Yes, we will :thumb:

I agree, based on your description, probably u-joints and coupler. Aren't boats fun?

 

[Lou C]

Yep fun, fun...
I always wondered, why did the marinizers not think of using a Rzeppa style constant velocity joint instead of u joints? They even come with their own rubber boot that could have been kept inside the regular bellows, like double protection...Modern Jeeps like the Wrangler, use them on each end of the rear driveshaft, no conventional u joints on the rear shaft at all, only on the front end of the front shaft, the rear end of that shaft also has a CV joint. Rzeppa joints run smoother than u joints for sure. I can say this because our '07 Jeep has CV joints in the front half shafts, vs our '98 that uses u joints, when running in 4x4 full time and turning, you can feel it in the '98, in the '07 not at all.

 

[AShipShow]

My best guess is... U-joints are cheap and strong... Pretty much the only two requirements lol

 

[Scott06]

My best guess is... U-joints are cheap and strong... Pretty much the only two requirements lol

Yes replacing ujoints us $10-35 each, last cv joint was closer to $100

 

[achris]

..., vs our '98 that uses u joints, ..

WOW, can't believe Jeep are so far behind the times. Toyota, Nissan, Mitsubishi and Suzuki have all been using CV joints on their half-shafts since the 60's....

Well, actually I can believe it. Jeep has the WORST reputation for both vehicle quality and customer service this country has had the misfortune to see since, forever....

Chris......

"Friends don't let friends buy Jeeps", told to me by a Jeep salesman!

 

[120mmAPFSDS]

Having quite a difficult time getting the drive off. Got the trim cylinders detached and the six locking nuts removed and the drive is moving a little bit but it seems like something on the inside won't let it go, like something is gouged into something and holding it in place. Also got a lot of dark green gear lube leaking out from the crack, not sure if this is supposed to happen. I couldn't get it off with the help of a friend. Any ideas?

 

[Lou C]

WOW, can't believe Jeep are so far behind the times. Toyota, Nissan, Mitsubishi and Suzuki have all been using CV joints on their half-shafts since the 60's....

Well, actually I can believe it. Jeep has the WORST reputation for both vehicle quality and customer service this country has had the misfortune to see since, forever....

Chris......

"Friends don't let friends buy Jeeps", told to me by a Jeep salesman!

I'm sorry to have to disagree with you Chris but here's been my experience with 2 1998 vehicles, one we still own, the other we don't:
1) 1998 Subaru Legacy Outback, good the first 100K miles then:
blew both head gaskets at 109,000 miles, fixed that and leaky cam seals. Cost a bunch. Then at 185,000 blew them AGAIN! Job done by Subaru Dealer too. Additional annoyances: front CV axle boots failed 3 times, CVs themselves, once each side. Wheel bearings, both fronts failed, had to get done at dealer with special press, $500 each. Starter, alternator, radiator and water pump were done also. Gas fill pipe rotted out, leaked gas on driveway. Speed sensors and knock sensors both failed 2 times. Spark plugs wires were defective caused intermittent misfire codes in wet weather. After second head gasket failure, my wife decided to get another car (Subaru again!)

2) 1998 Jeep Grand Cherokee Laredo, 4.0 liter engine, Selectrac 4x4.
When new had a leak from the transfer case, and had to replace the horn pad (arcing caused horn to stick on). Warped OE brake rotors, fixed with better aftermarket. Replaced radiator, water pump, fan clutch and thermostat, also did A/C evap and heater core at the same time. Auto trans seals done at 80,000 miles.
What has not been touched:
Engine, not one repair, other than tune ups and O2 sensors
Front and rear axles, all original ring & pinions, bearings, u joints front driveshaft, rear driveshaft and front axle half shafts. All original and its closing in on 180,000 miles.

Both bought new, the repairs on the Jeep (except for the AC Evap and heater core, and trans seals) were much cheaper, simpler and I was able to do them all. Engine runs as new and does not burn oil.

So, let's not let the facts get in the way of the TRUTH....

PS:
My '07 Hemi has been much better, very few repairs, in 12 years and 110,000 miles, (starter, front diff bushings, rear pinion seal, rear CV on front driveshaft). That's it.....

 

[AShipShow]

Having quite a difficult time getting the drive off. Got the trim cylinders detached and the six locking nuts removed and the drive is moving a little bit but it seems like something on the inside won't let it go, like something is gouged into something and holding it in place. Also got a lot of dark green gear lube leaking out from the crack, not sure if this is supposed to happen. I couldn't get it off with the help of a friend. Any ideas?

First: Do you have the shifter in FWD gear?

Second: You have a gear lube reservoir somewhere in the engine compartment, usually port side on top of the motor. If its not too late, you should put a pair of vice grips on the hose from the bottle to minimize fluid coming out when you seperate the drive. There is a little poppet valve between the bell housing and the drive shaft housing on the outdrive. When the drive is installed, it depresses the poppet valve and allows gear oil to flow from the lube monitor to the drive, when the drive is removed, the valve seals off and stops the fluid from leaking... A little fluid leak is normal, but if your drive is stuck and only a 1/8" or so off the mating surface, the valve is probably slightly depressed and letting your lube monitor leak continously until its empty.

The fact that your drive is hard to remove is not entirely uncommon, but it means your motor is probably out of alignment. Sometimes theres no good solution other than to put a block of wood under the skeg and lift the drive and let it drop onto the wood block. This can jar it loose enough to get out. If that doesn't work, sometimes your only option is to work in a prybar or long screwdriver between the drive and bell housing. But if you do this, YOU NEED TO BE EXTREMELY CAREFUL not to mar up the mating surfaces or certain areas will not seal.

Once you get the drive off, you need to use an alignment bar and make sure its aligned before struggling to reinstall the drive.

Also, before you remove the drive, don't forget to disconnect the speedo hose.