900 stx

[BEECHFRONT]

i recently purchased a 98 stx with no compression in rear cylinder upon removing the cylinders i found the rear piston had a hole in the side below the crown on exhaust port side after removing the motor i noticed the oil line for rear carb was off were it connects to oil pump.

i was wondering if lack of oil could cause a piston to detonate?

[Technical Support]

No it won't.

[BEECHFRONT]

what should i be checking short of splitting the cases?

[BEECHFRONT]

anyone?

[langford2000]

Hello Beechfront, short of splitting the cases you could check the carbs to see if there is a problem. However if you have a piston with a hole, then a top-end rebuild is in order. Also the possibility of crank bearing contamination is VERY high. You could chance it just putting a top-end on the boat but you will be kicking yourself if the crank lets go later on. IMO go with the SBT rebuild and rebuild you carbs. Then use a high quality fuel - not that mom and pop fillerup joint or marina fuel. I know of two engines that belonged to friends of mine that died that way.

Hope this helps
James [img]/graemlins/winkanim.gif[/img]

[BEECHFRONT]

thanks James, i ended up splitting the cases and inspecting the crank, i was going to chance it but i will inspect everything ,

im surprised no one else chimed in?

i thought that is what this site is for tech support? guess all the techs are more interested in the general discussion section of this site?

[Technical Support]

Lang already gave you good advice, I just dodn't have anything else to offer, chill.