1989 Mercruiser I/O 3.7

bfdff4422 · Apr 24, 2010

Hi new to boats. I was out in my 19' Mercruiser and after an hour of running it stopped dead in the water. I check all wiring and that all checks out good. A friends said it may a timing chain. Is there a timing chain on this style motor? Please help thank you.

solar7647 · Apr 24, 2010

Re: 1989 Mercruiser I/O 3.7

Yes there is a timing chain, but it hard to say what your issue is.

Lets start with this, have tried to restart it?
What happed when you did?

Bt Doctur · Apr 24, 2010

Re: 1989 Mercruiser I/O 3.7

in as many words as needed describe what it dosent do
no battery power, no power to starter, turns over but dosent run, tries to turn and stops, engine and drive oil checked for level .

bfdff4422 · Apr 24, 2010

Re: 1989 Mercruiser I/O 3.7

It has 12.8v at the batt. When you turn then key it tries to turn the flywheel but it cant after it tries to turn crank you can hear a clicking noise. I checked the oil and it good.

Bt Doctur · Apr 24, 2010

Re: 1989 Mercruiser I/O 3.7

1 It just stopped when you were running it ? A quick stop can hydro-lock the cylinders, pull all the spark plugs and try to spin the motor
2 If you sat for a while, may be a leaking riser hydro-locking the engine, pull spark plugs and check
3 If just stopped, the drive may be seized from lack of oil
Only #2 may be caused by a bad starter not turning the motor aside from the leaking riser

bfdff4422 · Apr 24, 2010

Re: 1989 Mercruiser I/O 3.7

Thank you i will try that ASAP. Have a great weekend

solar7647 · Apr 24, 2010

Re: 1989 Mercruiser I/O 3.7

bfdff4422 said:
It has 12.8v at the batt. When you turn then key it tries to turn the flywheel but it cant after it tries to turn crank you can hear a clicking noise. I checked the oil and it good.

It wont turn the fly wheel at all?
Pull plugs look for water, and try it again with no plugs.

bfdff4422 · Apr 24, 2010

Re: 1989 Mercruiser I/O 3.7

I have removed the plugs and tried it and still nothing. Then i tried to turn the fly wheel with a socket wrentch and cant turn it. Also checked the oil to see if it had water in it and that was good as well.

Juniinc · Apr 24, 2010

Re: 1989 Mercruiser I/O 3.7

Is the drive still attached?
I would check the outdrive oil level first,,,

bfdff4422 · Apr 25, 2010

Re: 1989 Mercruiser I/O 3.7

Where is the outdrive oil loc? Yes the drive is still attached

bfdff4422 · Apr 25, 2010

Re: 1989 Mercruiser I/O 3.7

Hey Guys just want to say thank you for all your help it was the upper unit that went bad. Have a great day and be safe on the water.

1989 Mercruiser I/O 3.7

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