new engine siezed

[radiocontrolhead]

ok. so heres the story, i buy a brand new engien from sbt, hoping it will run like a champ again. so i install it. old carbs and all. and it runs terrible. i get them rebuilt by bill at watercraft magic and it still runs terrible. i finally take it out today becasue i thought it was goign to run nice. and what do i find? my pto cylinder sized up. something entered the chamber or the rave valve hit it or somethign and now it lost all it's compression. the whole cylinder is toast.

how is this possible? is this why it was runnign liek crap on the low end side teh whole time? i'm thinking the it was just a bad egg from the start. i filed a warranty claim and i was wondering, do they give back the same engine? or do they send back a different rebuilt engine. i would find it easier on them to send me a new engine.

[1fastski.com]

Re: new engine siezed

if you took the engine apart you get nothen , if not you would get a new engine not your old one back , BUT if you ran it without rebuilding the carbs OR fixing whatever blew the orig engine its your foult the new one blew NOT SBTs { you need to fix the orig problem before running the new engine }

also Bill at WCM is one of the best in the biz so if he did the carbs i would bet money there right } ask him how bad they were if they were not that bad then look for another problem or you will toast the next engine you get .

[radiocontrolhead]

Re: new engine siezed

the piston looksl ike a chunk of metal went straight in there. and i dotn think thats my fault. it seems like the rotary vavle hit the top of the piston, that is where the damage is. i will try to get a picture of it. i know it wasn't my fault. i had the carbs rebuilt by bill at watercraft magic. so i know they were rebuilt. i did not open teh engine or anything so i hope i get a new engine back, and not the same one.

[1fastski.com]

Re: new engine siezed

it would be impossable for the rotory valve to hit the piston . when you ran it without rebuilding the carb the first time it would have takin about 20 sec to toast the piston if the carb were running lean .

[radiocontrolhead]

Re: new engine siezed

ok, i guess i didn't explain it too well. the problem at first was it was bogging very badly. it woudl not take off at all. i woudl have to hold the thorttle wide ope, wait about 4 second and eventually take off, once it was passed that little "bog" zone, it ran liek it used, however, today, i was goign to tune the low end and i wanted to make one top end run, i take it at a nice speed and let off the throttle to let it idle, then it dies, and i cannot restart it anymore. i'm thinking while i was riding it, i was running on one cylinder, because i coudl notice that it sounded a little different.

[radiocontrolhead]

Re: new engine siezed









btw, that blue stuff is teh rag i used to stuff the piston, it got caught on the sharp edges of piston damage. what coudl have fallen into the engine?

[1fastski.com]

Re: new engine siezed

from the scoring marks its just as i said , you ran it lean and stuck the piston the the cyl and now its broke , has nothen to do with SBT , now that your carbs are done when you get your new engine from SBT it should run fine . if you would have done that to any OEM engine you would be buying a new engine . so be sure to thank SBT for the best warranty on the market :-)

[radiocontrolhead]

Re: new engine siezed

how could they be runnign lean if the mixture was always the same? what woudl cause them to run lean? a dirty carb? or what? the carbs were rebuilt after 3 hours of use. woudl bad carbs cause the rotary shaft bearing to heat up and explode? here is a picture of what i'm talkign about. this is why my other engine failed.

[radiocontrolhead]

Re: new engine siezed





so now you are sayign that because i didn't rebuild the carbs when i installed the engine, that it siezed the engine up? i rebuilt them aproximately 3 hours of run time. this was because of the bad low end response and the fact that it woudl flood w/ fuel from sitting, i was told they were leaking needle/seats.

[1fastski.com]

Re: new engine siezed

pistons are scored , it only takes 20 sec to toast a piston , leaky N/S will flood the engine with more raw fuel and wash the oil away so yes flooding is bad also . when ever a 2stoke boggs fix it asap . when it come to fuel there is no room for mistakes.

[radiocontrolhead]

Re: new engine siezed

ok so what do i do now? wait for the new sbt engine? i ahve everything clear and cleaned. new oil pump, rebuilt carbs, new rv cover (sbt cover), what can i possible do wrogn this time?

[1fastski.com]

Re: new engine siezed

sit back and wait for the new engine , atleast you know your carbs are done { and with bill doing the work they were done right }

[Johnnylaw]

Re: new engine siezed

It's a hard lesson. and I learned the hard way myself. You need to find the cause of the first engine failure. My big mistake was taking my ski to a dealer. They didn't have any idea what caused my engine to fail with 98 hours on it. You don't run 3 hours on an engine that is not running right. Ask bill. He is the only guy I know of you can trust in California

[radiocontrolhead]

Re: new engine siezed

i have and he said that the way my engien sounds is the way it shoudl sound. however, he did do a compression check on my cylinder but it was the good cylinder, not he scored up one. i dont know if he did a compression check himself, but he showed it to me right there and it read a good 143 on the mag side piston. so maybe because the other piston was fried, it had a hard time running well. look at the other pictures. what coudl possible cause that bearing to fail? stress over time? what caused it to fail?

[1fastski.com]

Re: new engine siezed

your first engine just had a bad bearing , happin to a lot of 800s could have been an air leak into the bearing or just its time to go .