How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Tan Your Own Question
Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 11073
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
Type Your Boat Question Here...
Tan is online now
A new question is answered every 9 seconds

0lder stern drive mercruier engine runs great . bur took it

Customer Question

0lder stern drive mercruier engine runs great . bur took it out today at slow speed everything worked fine. ran up to 30 .000 rpms and suddenly soubded like I hit a log real loud like a thump. like it jumped out of gear and right back in real quickly slowed down and every thing was ok till I started back up to a higher speed and same thing happened a gain. your opion please
Submitted: 2 years ago.
Category: Boat
Expert:  Tan replied 2 years ago.
Hello. My name is***** the gear lube in the lower unit. What does the lube look like is it black and shinny? This sounds like the engine is jumping out of gear. What happens when the clutch dog and forward gear get worn on the lugs where the clutch dog engages the gear they start slipping out of gear and it's like hitting a log real hard. If you at lower rpms it will usually stay in gear but soon as you put a hard heavy full rpm load it will jump out of gear. Does this sound like what you have happening?
Customer: replied 2 years ago.
so by running the boat at first lub was thick and cool after a while it got hot and thinner
Customer: replied 2 years ago.
do you think this is right?
Expert:  Tan replied 2 years ago.
The lube will only tell us if there is any metal in the lube indicating something is tearing up in the drive. The thickness has nothing to do with the drive kicking out of gear.Have you checked the lube yet?
Customer: replied 2 years ago.
no it dark here have to wait till morning. if there is metal in the lub something is eating up the gear correct
Expert:  Tan replied 2 years ago.
Yes that is correct. The lube will look like it has glitter or there will be slivers of metal. Post back with questions.
Customer: replied 2 years ago.
ok thank you that's all we wanted to know.
Expert:  Tan replied 2 years ago.
Your welcome........Thank you........TanPlease don't forget to positively rate me as that is the only way I get credit for helping you. Thank you.......Tan