sending in sbt motor?

[jafo9]

so i'm gonig to have to send my motor back to sbt. it's seized 3 times and for the life of me i can't figure out why. runs fine 0-50% throttle, beyond that for any extended time seems to equal seizure. carbs and entire fuel system basically replaced/rebuilt/cleaned.

my real question is this - i purchased the premium motor from sbt about 6 months ago. the ski never ran right even after installation. i'm only now getting to work on it again. i ran the 2 breakin tanks and then it began to display the problems so not many hours on the motor/gaskets. do i have to purchase a new gasket kit or will they send a new one with the motor. if a new gasket isn't included, can i reuse any of the gaskets or do i have to buy a whole new kit.

sorry to sound cheap, but i've already invested an unbelievable amount of time and money in my 96xp. the only thing it does well is take up space in my garage. my children have gotten to hear daddy say new and exciting words while working on my yellow boat anchor.

[Steve762us]

Re: sending in sbt motor?

It "seized" three times?

Sounds like you voided your warranty, by going in and re-building it after the first "seizure".

What all parts did you replace, each time that it "seized"?? Pistons, rings, cylinders?



You probably have fuel delivery problems, if the engine really seized. Shame that you didn't just send the engine back to SBT after it first "seized", got a warranty replacement, and then fixed your carb issue before installing the
new engine.

[skisol]

Re: sending in sbt motor?

It seized after break in, is your oil injection working correct, or are you running premix?

Anyway the internal parts should tell you why it seized, do not just drop another engine in, you must get to the reason of failure first, post pictures etc.
Or like you said it will be going back to SBT, they will determ the cause and let you know.

[jafo9]

Re: sending in sbt motor?

i never cracked open the motor so i don't think i voided the warranty. after each seizure i would head back to the shop and work on the carbs. i never could find the problem but it did seem like a delivery problem. i replaced the carbs, replaced the oil pump. tested pop-off, oil pump delivery, and anything else i could think of.

i may have found the problem though. on taking the motor out for return to sbt, i found the little plastic key that drives the oil pump with all the legs broken off. from the outside of the flywheel housing it looked fine, but on removal of the housing cover, i found all the plastic legs at the bottom of the mag cup. i'm assuming that the oil may not have been turning much at all, or maybe a little. i would think that unless it was turning full rpms it would cause a lean condition.

anyway, it should be on its way back to sbt sometime this week.

[dsolie]

Re: sending in sbt motor?

Yup.. A broken oil pump driveshaft will make your ski have NO lubrication, causing a seizure real quick..

Also, a little bit of advice, there are very few times (1-100) that you can seize a motor and it will be just fine (no terminal damage). Once you seize, you have seized.. The rings have left marks, the bearings have started to fail, the damage has been done. Sure, the ski may fire right up 2 minutes later, but she is NOW, as you call it.. A "yellow boat anchor", with a timebomb motor.

[gr8jpn]

Re: sending in sbt motor?

SBT will send you a new gasket set with your replacement motor.
(I just got a replacement motor from them)

They also sent a sheet that explained what caused my first motor to fail.

I am guessing from what you found.. the report will say something about lack of oil.

Be sure to get oil into the crankcase of that new engine before you start it up!

[Rocky 1]

Re: sending in sbt motor?

ok several things that were not covered you said 96 xp
1. due to the type of oil pump shaft premix!
2. Timing when you replace the motor, crankshaft, flywheel, pick up you need to have it timed you will need to find the timing correction and have your key programed. For this you need a pulse tach,timing tape,pointer,and a dedicated dc 2 stroke timing light. If your timing is off you can toast a motor.
Don't worry SBT will hook you up and let you know what happened.