Mercury 350 35hp, locked up? or Not !!

lynnyrd

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May 8, 2001
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16
I bought a fishing boat with a Merc 350, I felt like the motor was locked up but the deal was so cheap I bought anyway. I checked the flywheel and it would not move at all. Before giving up on the motor I decided to put some WD-40 down in the spark plug holes and see if it would loosen up, so for three or four days a few minutes a day I have been trying to move the fly wheel with a hammer and screwdriver, and wd-40, today it moved. By hand I can move the flywheel an inch or so in both directions, with the hammer and screw driver I can move the flywheel about 3 or 4 inches in both directions. I could have continued with the hammer but decided to stop and let the wd-40 work some more. when I move the fly wheel I can see both pistons move thru the spark plug holes, and the prop also moves. My question is am I waisting my time, is there any hope for this motor without a rebuild. Thanks for any help.
 

ODDD1

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Jan 23, 2001
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Re: Mercury 350 35hp, locked up? or Not !!

lynnyrd...kick it in the ditch an toss a match on it...their day is done......
 

lynnyrd

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Re: Mercury 350 35hp, locked up? or Not !!

Thanks for the input, I was hoping for some ray of hope, are there any 2nd opinions? Maybe I should move on to the Mercury Mark 58a that was thrown in with the boat, its not locked up but might be a little big for the boat.
 

12Footer

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Mar 25, 2001
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Re: Mercury 350 35hp, locked up? or Not !!

Instead of kickin it in the ditch, kick it outta gear. This will eliminate the lower unit as being the culprit.<br /><br />Also,when u turn one over counter-clockwise,it changes the direction of the impeller.So once you get her freed-up, be sure to change it (just outta principal).<br /><br />But let the WD40 do it's magic,and keep taking it easy,and you might get it.<br /><br />I would remove the head first,and check the condition of the piston and cylinder walls.<br />If it's scored-up real bad, well...There's allways the ditch and matches.<br /><br /><br />------------------<br />Sandbar? Sandbar? I don't see no stinking sanDBARRRrrrrr!!!
 

lynnyrd

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May 8, 2001
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Re: Mercury 350 35hp, locked up? or Not !!

Thanks 12footer, I did pop it out of gear but it stayed the same although it seems to move a little more each time I try. I tried putting my finger over the spark plug holes and turning the flywheel, I can feel good pressure on the bottom hole, but not much on the top one, this could be bad!! Should I put my steele toe boots on?
 

dcsjr

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May 14, 2001
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23
Re: Mercury 350 35hp, locked up? or Not !!

lynnyrd-- If you have access to an air compressor you could buy a fitting that fits in the sparkplug hole (sold at auto parts houses about $5). Put some oil in one cylinder, let stand a few minutes, then plug on compressor line and slowly raise pressure. The air should push the piston down. If it doesn"t, expect the worst. Once the piston is down try and get a look inside with a flashlight and maybe a small mirror. If rusted and/or scored just re build. If not do the same with the other cylinder. good luck
 

ODDD1

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Jan 23, 2001
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1,054
Re: Mercury 350 35hp, locked up? or Not !!

12 footer it doesnt matter what gear the motor is in....all the gears are meshed all the time..the only thing you unhook is the propshaft.....
 

lynnyrd

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May 8, 2001
Messages
16
Re: Mercury 350 35hp, locked up? or Not !!

ODDD1, If I remove the lower unit and it frees up then my problem is in the lower unit, if it stays the same then my problem is in the top, is this correct? Also how easy is it to take off the lower unit. In the end it does not matter if I get this thing going I'M just having fun learning, Thanks for all the help!!
 

12Footer

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Mar 25, 2001
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8,217
Re: Mercury 350 35hp, locked up? or Not !!

Yes, ODDD1. But if he can get it into neutral,turn the prop by hand, and it's still locked-up at the powerwhead....<br />That's simply all I was looking to eliminate there (lower unit).
 

12Footer

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8,217
Re: Mercury 350 35hp, locked up? or Not !!

I see what u mean ODDD1, it isn't gonna splain much is it?
 

ODDD1

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Jan 23, 2001
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1,054
Re: Mercury 350 35hp, locked up? or Not !!

Nope...dropping the lower unit off will answer the question...
 

Frank

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Apr 9, 2001
Messages
14
Re: Mercury 350 35hp, locked up? or Not !!

35 years ago my dad bought me a 1956 10 hp Johnson outboard for $35 that was locked up. Filled it with penetrating oil and let it sit for a week. Loosened right up and has been running ever since. You never know.
 

corm

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May 12, 2000
Messages
1,241
Re: Mercury 350 35hp, locked up? or Not !!

Hi<br />I got about 10 of them laying around If you need one email me ($75.00)<br /><br /><br />------------------<br />...have fun...corm<br /><br />cubic inches = power<br />power = speed<br />speed = FUN<br /><br />Email me if you need to.
 
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