1989 Mercury XR4 150hp wont turn over

damien01

Recruit
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Aug 6, 2012
Messages
2
Hi, I just recently bought a 1989 astro quickfire bass boat. It has a Mercury XR4 150Hp outboard motor on it. Today I just tried to start it and it did. But it revved really high and I turned it off right away. Now the flywheel wont turn. When in neutral the prop spins. Then in forward the prop spins but makes a really loud clunking noise in the lower end about half way down. I put it in reverse the prop does not spin either way. Any idea on how bad the motor is now? Could it be fixed easily if I got a service manual?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: 1989 Mercury XR4 150hp wont turn over

Sounds like the gearcase is fine. Did you mix oil with the gasoline, or does the motor have a functioning oil injection system? Remove spark plugs and spray motor with penetrating oil. Maybe she will unseize.
 

aussieflash

Lieutenant Junior Grade
Joined
Feb 5, 2011
Messages
1,004
Re: 1989 Mercury XR4 150hp wont turn over

As Chris said gearcase sounds good.Prop is doing what it should do.
Are you trying to turn flywheel by hand?or is starter not engaging?Did you blow bluish smoke?
Mine always revs high as most due to open throttle to start then quickly lower when started.Otherwise it sounds like you just leaned out which will cause high idle.
 

damien01

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Aug 6, 2012
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2
Re: 1989 Mercury XR4 150hp wont turn over

Its has a oil injection system. I dropped the lower half and the motor turns over. The long shaft from the lower end to the motor doesn't move. Not sure what's inside of it that might be locked up. But the motor is suppose to rev up that high when it starts? How long do I leave the high idle lever up after its running? Sorry its my first boat for my father and myself so we both are kinda new to this. And we bought it cheap due to a previous buyer returning it cause he claims it was spraying oil all over when he put it in gear.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: 1989 Mercury XR4 150hp wont turn over

OK, so the driveshaft has seized. Remove the stainless steel drain and plugs on the gearcase and see if any gear oil comes out. Probably the gearcase is bad and needs replacement.
 

aussieflash

Lieutenant Junior Grade
Joined
Feb 5, 2011
Messages
1,004
Re: 1989 Mercury XR4 150hp wont turn over

lower plug has magnet.Any metal on plug?Check upper drive shaft splines,they may have sheared causing the high idle issue.
 
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