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Oil leak on brand new 300HP Verado - dissapointed is an understatement

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Avalon25

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I recently took delivery of an Avalon Pontoon with a 300HP Verado. After taking it out on the water a few times I noticed motor oil leaking from the lower engine cowling. The boat is less than a month old and to say I'm disappointed is an understatement. My dealer jumped on looking at and spoke to Mercury and they felt the likely cause was the upper crank seal even though my engine serial number did not fall in the affected range. The crank seal was replaced and I got it back and nothing has changed its still leaking oil.

My fear is the next step is to continue to dismantle more of this brand new motor to find the leak. I just want the motor replaced with a new one. I don't want a brand new motor that has to be all taken apart and put back together. I'm still hopeful that the leak is being caused by something minor. If anyone has any suggestions as to what might be the root cause of the leak please let me know. My inspection of the motor has me leaning toward the source of the leak being in the lower portion of the motor not the top. Unfortenetely its very difficult to see the lower part of the motor due to the lower engine cowling. Any help is appreciated.
 
Ha, Jeff....you said it. Is the oil actually "leaking", or is it residual from the exhaust.....floating on top of the water. How could an "upper crank seal" cause oil to leak out the bottom?......unless it's running all the way down the motor? Does it leak only when running?
Note: I agree, sure wouldn't want a dealer doing major repairs on my new truck or car......if I ever was stupid enough to buy one! Honestly, I really love to drive....like to TELL my truck what to do......not have my truck tell ME what to do. Drive a 74 Chev.....the old ladies at the gas station think it's pretty cool. So what if I gotta open the windows with a crank handle.
As mentioned by Chris.....these big Mercs need to be "broken in".....proper proceedure needs to be followed. Avoid high quality synthetic oil, like Amsoil, until after full break in.
 
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thanks guys. Maybe I should have been more clear on the severity of it. See the pics. Basically the oil is collecting in the lower part of the engine compartment and when I tilt the motor up when beached or back at the house oil drips out of it, runs down the chaps and drips on the ground or causes an oil sheen on the water. Are you saying this is normal for a brand new motor?
 

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Docksidemarineservices said:
All new engine pass oil until they are broken in and the rings are seated.... Put some hours on it.
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Thanks, Chris. See my pics above. Is there any chance the oil was overfilled at the factory and its breaching out somewhere? The oil level doesn't seem to have moved much on the dip stick. however I haven't driven it much since the oil appeared at about 4hrs on the motor.
 
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I just install a pair of Verado 300HP. I went to test them yesterday and one of the motors did not reach the 5700 RPM on WOT as the 2nd one. it did 5000RPM. We return to dock I saw the oil leaking on it, after searching with the motor off and on, we found it on the to of it, see the picture. I am disappointed too because it is a brand new and I don’t want to somebody get it apart and repair it.
 
4windsint said:
I just install a pair of Verado 300HP. I went to test them yesterday and one of the motors did not reach the 5700 RPM on WOT as the 2nd one. it did 5000RPM. We return to dock I saw the oil leaking on it, after searching with the motor off and on, we found it on the to of it, see the picture. I am disappointed too because it is a brand new and I don’t want to somebody get it apart and repair it.
Click to expand...

Sorry to hear you have a similar problem. I don’t see the picture you mention? If your oil leak is visible from above maybe you have the upper crank seal issue. My motor seems to run fine and can get to 6000 rpm without an issue. I’m going to be taking it in soon to root cause this oil leak issue. I’ve been running it on the weekend and watching the oil level closely.
 
I am dealing with the same issue with oil leaking on the lower part of the block. Any updates as to what the problem and resolution was?
 
I am dealing with the same issue with oil leaking on the lower part of the block. Any updates as to what the problem and resolution was?
 
Is your thinking that two engines having an oil leak will have the exact same source and type of leak?

The solution to one problem is not always the solution to another problem, even though the problems are the same.

Why not get the motor into a shop and let a mechanic find out what exactly is your problem? Once the problem is known it can be fixed.
 
My thinking is I am looking for an answer as to what the problem was with this particular oil leak. I am doing my due digilence so that I can understand what will be necessary in order to resolve a similar problem. I have quad 300s with 20hours on a 40ft boat with a full tower. I have already paid Mercury dealer $300 to come and check. They have to pull the boat out, pull the covers, and run the motor to find the leak. Getting the boat to a shop is not as simple as pulling a trailer around and loading the boat. I have to have the boat hauled out and then the motor cover removed, then they have to run the motor to see where it is leaking. Hauling a boat requires a heavy lift and there are daily storage fees. If my problem is the head gasket then this will become a major operation and will require finding a facility that will provide a fork lift.
I just spent 140k on this repower so I would not have problems and now I have problems. Go Mercury!
 
Avalon25 said:
I recently took delivery of an Avalon Pontoon with a 300HP Verado. After taking it out on the water a few times I noticed motor oil leaking from the lower engine cowling. The boat is less than a month old and to say I'm disappointed is an understatement. My dealer jumped on looking at and spoke to Mercury and they felt the likely cause was the upper crank seal even though my engine serial number did not fall in the affected range. The crank seal was replaced and I got it back and nothing has changed its still leaking oil.

My fear is the next step is to continue to dismantle more of this brand new motor to find the leak. I just want the motor replaced with a new one. I don't want a brand new motor that has to be all taken apart and put back together. I'm still hopeful that the leak is being caused by something minor. If anyone has any suggestions as to what might be the root cause of the leak please let me know. My inspection of the motor has me leaning toward the source of the leak being in the lower portion of the motor not the top. Unfortenetely its very difficult to see the lower part of the motor due to the lower engine cowling. Any help is appreciated.
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Let me start off saying that this is a major issue if you have these engines. I have a center console with 3 - 2021 300 Verado’s with less than 350 hours on them and one has been leaking oil nonstop. I’ve had the seal replaced twice so far by 2 certified Mercury mechanics and just put in a call as it’s leaking again. So disappointing the amount of money you pay for these engines then follow up with cost like this…. Absolutely crazy that everyone you talk to has known about this and/or had one leak. Think about this read if you’re looking to buy one. When the technicians all talk about it…. You know it’s an issue.
 
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