my boss bought a lake house that came with a pair of msx 150's. he messed with them and couldn't get them to run.. long story short he gave them to me to see if i could do anything with them.. one i don't have much hope for. after looking it over, i found oil in the water. don't know how long its been in there. i am going to take the chance and try and flush the engine with rotella 15-40 and see what happens, after all i don't have anything in them thus far. any pointers or recomendations on the best way to do this?

i got the second one to actually start and run. took it to the water and let it run on the trailer for about 10 min. every thing seemed ok thus far. backed it off the trailer and took of. ran about a hundred yards and cel started flashing with a temp warning on the display, and it fell on its face and died coming off plain. floated around for a min and finally got it to restart. cel flashed 10 times then went off (im assuming this is normal as it did this when i first started it up). took off again and made it almost back to the ramp and same thing... cel flashing and temp warning on the display. after getting the machines and doing some research on the net i came across this site which is a gold mine for info on them. pryor to heading out i read through this forum pretty extensively looking for common issues with them.
so i pulled the one wire temp sensor in the exhaust housing. fired it back up and took off again.. just about got plained off and it did it again.. the whole time this is happening it dosent smell or feel like its over heating. so heres the question... what the best way to check and see if the water pump is moving water in the closed loop cooling system to make sure the plasting gear isnt stripped. is there anything else i need to look at that might cause this.

i dont have very much history on the machines the both have around 70-80 hrs on them according to the display. i know they have been setting for at least a yr. the one that runs has had the sifb bypassed. the other one has not. the previous owner (before my boss) obviously messed with them. in a box that came with the jet skis i found a dw disk and diag cable w/usb adpt. unfortunately for me the disk is cracked and i cant load it on my lap top.

im mechanically inclined and dont mind putting a little into them to see if i can bring them back. but im not going to ride a sinking ship to the bottom.. if i cant get them both running or make one good one out of the pair, ill probably just sell them as is. or part them out.

sorry about the novel lol
and thanks for any help in advance.