Yamaha 150 blown?

tigger3386 · #1 July 27th, 2009, 01:07 PM

I wanted to tell you guys about my motor problems that I had this past weekend. (150hp 2 stroke, 2000 year model) I was running along half throttle and all of the sudden my motor started knocking. I pulled the throttle back quickly and cut it off. Then I fired it back up after making sure I had oil in the tank. It ran like crap, so I cut it off again. We then pulled the spark plugs to see if there was any compression and they all felt like they did. (by hand) We then took the oil lines off from the resevior tank that goes to the motor and I hit the key to turn it over. No oil came out of the lines. Keep in mind no alarms went off. I then talked on the phone to a friend and he said to put oil in gas tank to mix it the old way. When I tried that it sounded like dry metal on metal scrubbing. After gininng the engine a few more times either the battery went dead or she locked up too tight to turn over. So we got towed in by a friend. I talked to a mechanic and he told me to check the lower unit oil, the resevior drain tube and both of those oils looked ok with no water or smell to it. Then I took of the cover and I could turn the fly wheel by hand. So now he told me to take off the lower unit and check for a barring the might not have oil to see if that could be it. I think it is a power head but I am no mechanic. Any thought would be very helpful. Thanks!

Eshaw150 · #2 July 27th, 2009, 01:25 PM

take the lower unit off first a lot of people think that the powerhead is loked up when it is a seized lower unit berring or locked lower unit the drive shaft not being to turn will keep the powerhead from turning keep in mind that it goes powerhead driveshaft transmission not like a car.

robert graham · #3 July 27th, 2009, 01:57 PM

check compression on each cylinder with a compression guage. If they're all good, then look elsewhere. If a cylinder is low, pull off the cylinder head and see what's up. sounds like a piston/cylinder is fried. Good Luck!

tigger3386 · #4 July 28th, 2009, 12:32 AM

Thanks for the help guys. I am going to drop the lower unit this week. If anyone else has ideas or a good place to buy parts for it will also help me. Thanks