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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 16116
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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Mercruiser 470 startup after 10 yrs. I am trying to find a

Customer Question

Mercruiser 470 startup after 10 yrs. I am trying to find a way to turn the crank. The problem is that the motor mount on the front "forward" side is in the way. This motor has the alternator fix on it also so there is a belt on the front of the balancer.
Submitted: 2 years ago.
Category: Boat
Expert:  Jason replied 2 years ago.

Hello my name is ***** ***** am I speaking with?

Does the alternator have a big nut on the end?

Customer: replied 2 years ago.

it does, That may work, I can try to tighten the belt and see if I can get the pistons to move slightly.


Expert:  Jason replied 2 years ago.
Hi Doug.. When the engine runs the input shaft and the vertical shafts on the sterndrive also turn at the same time. So if you pull out all of the spark plugs. Tighten the belt. And put a ratchet on alternator pulley and try and turn it clockwise. As long as the engine, or the sterndrive are not seized, it will turn. To be honest you should be able to get it to turn by putting your hands on the large pulley as well if you can get a good grip on it. If it will not turn, then either the engine or sterndrive is seized up. What you would do next is pull he sterndrive and see which is seized and which is not seized. At the same time..... You might just want to think about sticking a battery in it and hitting the key. If the engine is good to go it will spin over. If it doesn't, it's not an issue that would be corrected by putting oil in the cylinders. Does that make sense?
Customer: replied 2 years ago.

There is no way the alternator pulley will turn the engine in its condition. I was looking for a way to turn the crank with something with more torque like a breaker bar. The sterndrive and plugs have been removed

Expert:  Jason replied 2 years ago.
It sounds like the engine might be seized from sitting. Have you hooked up a battery and tried the starter?
Expert:  Jason replied 2 years ago.

If it will not turn with the starter the engine is going to be stuck. Without pulling the engine the only way you might have success in turning it over is by using an stermdrive input shaft. I don't know if you work in a shop, are friendly with a dealer or not. But if you are, see if they have a junk input shaft for an alpha kicking around. If not, what you would do is press the ujoints out of yours so you can take it off. From there you would remove the hing pins on the gimbal ring, and remove the bell housing from the transom. After that you would have enough room to slide the input shaft in back through the gimbal bearing. And then stick a cheater bar/iron pipe through the eyes on the input shaft. And try to rock the crankshaft back and forth that way.. Does that make sense?

Also, if it is stuck.... Add some acetone to the cylinders..... It will thin out the mystery oil and help it creep past the rings.

Expert:  Jason replied 2 years ago.
Hello, just checking in. Did you still need help on the issue?