Need help rebuilding SBT rebuilt engines!

[esg]

Need help rebuilding SBT engines. Short story to this rebuild goes like this: I bought two rebuilt SBT 717 engines and two rotary valve covers and rotary valves for my 98 Sportster 1800. I broke them in per the instructions giving to me by SBT tech dept. I lived in Alabama at that time and prior to replacing the original engines with these crap SBT rebuilts I never winterize the engines since it rarely gets to 30 deg F in winter and never had a problem. So I broke them in then had to put the boat in storage since I had to go overseas for a year, when I returned I tried to fire up the engines and come to find out they were locked up, rusted so bad I cannot imagine how a fresh rebuilt engine after just being ran for no more than four hours to break them in got so rusted out. See pictures posted. The gasket surfaces between the piston bores and case halfs are severely pitted in my opinion. My question is, should I clean up these case halfs and reuse them or junk them and get good clean ones with no pitting? Also the case half's and piston bores had some kind of sealant between them in addition to the paper gasket, my understanding is that there should be no sealant used, just the gasket and when I looking at the service manual it doesn't specify and sealant just the gaskets. I'm wondering if the pitting in the case half's has anything to do with the engines not sealing properly and rusting out. One more thing to mention about these SBT rebuilds is that, one of the engines has the pulse line port on the magneto side and the other engine the pulse line port is on the PTO side. Both the original engines had the pulse line port on the magneto side next to the fuel pumps. The rotary covers which are also SBT rebuilds are severely scored and were installed at the same time the engines were replaced. I bought a top end kit from fullbore and the cranks look good no rust, just cleaned them up really good. The issue I think is the case half's with the pitted gasket surfaces. Sorry if this post turned out to be a bit lengthy but I feel I should mention everything I noticed that is off about these SBT rebuilds. Any help with rebuilding these engines, guys, would be greatly appreciated! since SBT ripped me off of about $2500 for the engines and rotary covers I'm going to do the rebuild myself. Thanks in advance for the help and advice on this rebuild!

 

[Poormanracing]

You said you didn't winterize them.all that rust has nothing to do with how many hours you put on.this is your problem and your fault because you did not fog the motor.these motors sit in a sweaty environment if the sit in a non climate controlled area they rust.it is steal cyl liner with steal wrings.

 

[Poormanracing]

Clean all the surfaces on a flat stone.the pitting is normal and won't hurt a thing as long as the sealing surface are good.all these companies use core parts and salt water eats the cooling passage if they cleaned and welded then resurfaced all the pitting then rebuilds would be twice as much.but as far as your motor rusting that's what happens when you don't fog them then let them sit.

 

[esg]

Prior to replacing the original engines with these SBT engines I never had to winterize them year after year and never had a problem, started right up no problem. Then I buy these SBT engines and use them for 4 hours and they get rusted beyond belief. Any idea how the salt got into the cylinders? see attached pics of the cylinders. Also any idea how the rotary valve cover got scored during the 4 hours of break-in time? Thank you for the insight on the pitting and how to clean them up! You've been a great help!

 

[Poormanracing]

The original motors where prob just as rusted but you never noticed because it didn't sit so long I'm assuming.these motors sweat alot with changing Temps and if you don't flush them real good or run them in fresh water the water stays in the water box's and just like a car near the ocean the humidity in the motors eats steal.as far as the rotary valve if the carbs or air box isn't clean gasket material or if the rotary valve was blocking one port will leave rust debris on valve and will scuff up the cover and block.when you are done with the boat fog it for a bit.wont hurt a thing.also add a little marvel to the fuel.maybe a 1/2 ounce per gallon don't have to be perfect but a little extra to protect.and if you think it might be the last ride then go a little heavier on the mix.incase you can't fog it

 

[Poormanracing]

You can tell that there was salt water or brackish water left over in exhaust by the scailing on the piston crowns.i looked at the pictures again.and if they are a year old did you get the 2 year warranty or if it is close to a year and only has 4 hrs on them maybe they will do something for you.

 

[Poormanracing]

You can tell that there was salt water or brackish water left over in exhaust by the scailing on the piston crowns.i looked at the pictures again.and if they are a year old did you get the 2 year warranty or if it is close to a year and only has 4 hrs on them maybe they will do something for you.how many tanks of fuel did you run thru and did you ad some oil to the fuel?I'm not cheer leading for sbt but just trying to help you prevent this from happening to you again.ive been in the sea doo repair bizz for 30 plus years and seen this on salt water boats all the time

 

[esg]

You can tell that there was salt water or brackish water left over in exhaust by the scailing on the piston crowns.i looked at the pictures again.and if they are a year old did you get the 2 year warranty or if it is close to a year and only has 4 hrs on them maybe they will do something for you.

I already took them apart and got a top end rebuild with forged pistons from fullbore, so I'm going to rebuild them myself. I'm just a little skeptical about the pitting on lower case half's. One of the cases has the pulse line on the PTO side instead of the magneto side, the original engine had the pulse line on the magneto side which is where the external fuel pump mounts to. Thanks for all the advice you have given me so far, it's helped a lot!

 

[Poormanracing]

Where the pitting is will not be a problem that is where the water flows thru like I said put it on a flat stone and clean it up.the pulse line is fine also just extend the pulse line.i would of gotten cast pistons for that personally.i have had some guys have problems early season with scuffing when the water is cold and not enough heat in the motor.just be mindful to let it warm up to temp everytime you start it. Especially if you have a guest use it