Broke a 575 SCi
 

On our way back from a Michigan City run my starboard engine would not run over 4000 rpm. At 3500 it was at 3.5 pounds of boost. When I started it again to put it on the trailer it blew out black smoke and died after about 15 seconds. I didn't try to restart it.

The shop did a leak down test and found 0 vacuum in cylinders 2, 3 and 5. He also found water in the cylinders. They are going to tear it down this weekend for the insurance company. The port engine didn't sound right to me either. I'll try and post some picture of the damage when its torn down.

Anyone else break a 575?

Yes, they are efi and they have about 100 hours.

Roger,

Are they under Merc's warrantee still?

Sorry to hear that Roger. I hope it works out for you. I suppose if you want to look at the bright side it's not spring.

Sorry to hear it Roger :(

Mark,

The Merc warranties have expired but the person that owned it before me purchased an extended warranty that's good until 06. It cost $30 to transfer over to my name and has been the best 30 dollar investment I ever made. When the drives were taking turns breaking it cost me $50 each for the deductible. It cost them over $13,000. I understand that they do not offer this warranty anymore.

boatfreak
The way things have been going the port engine will be the spring project.

Chris
How are you doing? Still headed south?

best 30 bucks? sounds like you hit the lottery:D hope it all works out for you . :)

Are they going to do a comp check and cylinder leakge on the other engine? Sorry to hear of all the grief.

Yup Roger, still heading south. We leave Tuesday with boat in tow. No winterizing this year! If all works we will have a place in Florida by January and then I go back to school. Then we start looking for that little condo on the water in Michigan.....new boat AS WELL!

picture 1

picture 2

picture 3

picture 4 Any ideas why this would happen. If I don't have a good reason for the warranty company, its my problem.

If both engines look like this I would suspect bad fuel; low octane or water in the fuel. If just one, it could have run lean or overheated bad.

We had water in a suppliers tank (it was a gasohol automotive type), and the water in the guys tank blended with the gasohol, which can reduce the octane rating like 10 points. Several boaters were reimbursed for their repairs by the fuel company, Sunoco I believe.

You should have your fuel checked and pull the fuel filter and cut it open. Gasahol can clean everybody's tanks and all the crud will clog the fuel filters. This can cause fuel starvation.

If you can't find a cause, you may blow up again.

Check with the last place you got gas, to see if others had any problems. Supercharged engines are more inclined to have problem.

Good luck, John B

Not real sure what I am looking for in picture #4. Is it picture of between 1 & 3?

Picture 4 is a zoomed in pic of the third picture. Those two pic's are from the other side of the engine showing that gasket about ready to go also.
Dan

We will be taking the heads off the port engine soon. It should tell us allot.

I found out the previous owner of my boat lost a fuel pump (the electric one) just before he traded it in. Could this cause the gasket to start to fail?

Thanks for the pictures and explanation Dan.

Lean fuel can cause detonation witch can cause all kind of problems. Do the pistons show any signs of pitting, or are cylinder walls got scratches in them?

The gasket failing is really a safety valve. I would rather have the gasket fail or spark plug blow out then the other damage detonation can do.

High engine water temps, high intake temps, lean fuel, low grade fuel, & too hot of sparkplug are some of the things that cause detonation.

You're right, better to have the HG as a fuse...

Has anyone ever considered a dual / parallel electric FP system with check valves so if one dies the other carries the load and prevents this type failure?

We do it with race jeeps (rockcrawling) and have had good luck. This way you could just bench check your pumps once a yr or more if you wanted to.

Are there relibility issues with this FP? is it the same FP merc uses in other apps?

Roger, check both the block and the heads with a good straightedge to see if either is beyond the allowable tolerances. I think the tolerance for the head is .003 max.

Finding water in the cylinders.... I had a similar problem and was told that the silent choice Y pipes caused a vacuum even when just utilizing at idle speed. This vacuum caused water to be sucked down into the cylinders by the compression (I'm not a mechanic, so forgive me on the laymen terminology). Merc (off record) told me that the 500 EFI's and up shouldn't be operated w/ any form of Y pipe. I added CMI's, diverting the water from the pipes, and haven't had any further problems.

Merc warrantied everything but the labor. I was 1 month out of warranty.

I have 500 EFI's, but another guy I know w/ 575's had the same problem. Hope this helps!

I'd like to look at your plugs real close. They're going to be the answer to whether it was octane related detonation or fuel starvation. Look for teeny particles of shiny aluminum on the insulator.

I don't think I see any chicken tracks on the pistons...

My 575's don't have Corsa type exhaust, just mufflers on the tips. The head gaskets blew through to a coolant port and allowed water into the pistons.

I looked at the plugs and didn't notice anything shiny on them and the pistons arn't pitted. I will look closer at them tonight.

Thanks
Roger

Good luck Roger. I hope you figure it out.

Mark