Engine locks up when warm Cold does fine

mallen

Cadet
Joined
Jun 30, 2005
Messages
18
1984 Evinrude 150HP Starts cold runs out great no misses. Go two hundred yards it locks up and dies. Even the starter won't turn it over. Wait till it cools starts fine then the same thing happens again. Brand new plugs today. Took to the lake 1/4 throttle or less runs fine open her up and the same thing all over again. Barely got it back to the dock after long cool down. What in the world is going on? Please help!!!!
 

jfm1

Petty Officer 1st Class
Joined
May 14, 2004
Messages
355
Re: Engine locks up when warm Cold does fine

sounds like your overheating
 

mallen

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Jun 30, 2005
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Re: Engine locks up when warm Cold does fine

Someone else told me that but it doesn't seem to be overly hot when I take the cover off. And it is moving water fine.... The weep hole is weeping and it blows plenty of water out of the propeller hole. Has this happened to you before?
 

Walker

Captain
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Jun 15, 2002
Messages
3,085
Re: Engine locks up when warm Cold does fine

I bet you've already got one or more damaged piston/cylinders. A motor can pump water and still overheat. One, if its not pumping enough water, another reason is if the bypass valves are stuck closed, and another could be calcium/salt/crud buildup on the water passages in the block which in effect insulate the metal from the cooling water. I'd say its time for a compression test.
 

R.Johnson

Rear Admiral
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Sep 24, 2003
Messages
4,446
Re: Engine locks up when warm Cold does fine

When you say it locks up, can you turn the flywheel by hand? If you can't, and it has done this several times, you now have a replica of an outboard motor.
 

mallen

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Jun 30, 2005
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Re: Engine locks up when warm Cold does fine

OK I am an aircraft mechanic and I know how to do a differential air pressure compression check on an aircraft cylinder but I don't have the first clue how to do one on this. I am certain I need a guage of some sort. Second what PSI should they read at?
 

mallen

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Jun 30, 2005
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Re: Engine locks up when warm Cold does fine

NO you can't turn it by hand.... Even the starter won't turn it. Yes, three times!
 

mallen

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Jun 30, 2005
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Re: Engine locks up when warm Cold does fine

C'mon guys don't leave me hanging... How do I check these things. How do I see if it is getting hot? How do I check compression?
 

R.Johnson

Rear Admiral
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Re: Engine locks up when warm Cold does fine

You simply use an automotive compression guage, it should show right around a 100#. Cylinders should be within about 10# of one another.
 

mallen

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Jun 30, 2005
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Re: Engine locks up when warm Cold does fine

Great....Assuming that the compression is OK how can I tell if it is getting hot because just after it locking up I can go back and put my hands on the engine. It isn't too hot to touch.
 

Silvertip

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Sep 22, 2003
Messages
28,758
Re: Engine locks up when warm Cold does fine

A thermostat stuck shut will cause overheating. Improper ignition timing will cause overheating. <br />Lean carb mixture can cause overheating.<br />Plugged cooling passages can cause overheating.<br />Lack of lubrication (50:1 fuel mix) will definitely cause overheating and seizure.<br />If you've stuck this engine repeatedly, you would be advised to do a compression check and/or pull the head and check for cylinder scoring/piston damage. If you seized an aircraft engine repeatedly, I think you know what the effect would be on it. The same applies to an outboard.
 

mallen

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Jun 30, 2005
Messages
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Re: Engine locks up when warm Cold does fine

I am fairly certain due to color and odor of smoke and due to it using oil it is lubricating. Previously I could just restart the engine after a few minutes.. The last time I had to prime it repeatedly.
 

R.Johnson

Rear Admiral
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Messages
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Re: Engine locks up when warm Cold does fine

Something is wrong here! If that engine is siezing up, you should not be able to lay your hands' on it. Pull the drain plug on the gearcase, and see what the oil look's like.
 

mallen

Cadet
Joined
Jun 30, 2005
Messages
18
Re: Engine locks up when warm Cold does fine

Brand new oil in the gear case.... Installed 3 days ago???? Are we talking lower unit problems? The prop was rebuilt last year and reinstalled by someone else.
 

billaranguren@yahoo.com

Seaman Apprentice
Joined
Jun 20, 2005
Messages
41
Re: Engine locks up when warm Cold does fine

Try pulling the thermostats and see if it still happens. <br /><br />Another possibility is the wierd bearing system. There is some coposite hard plastic-like material that provides spacers for the ball bearings on the lower main. My old 80 Evinrude had an odd sound, which later was proven to be all the bearings being pushed around in a funny way after the spacer broke, and all the bearings piled up. Eventually it locked up also. <br /><br />Bottom line something is locking up the bearings, or a piston. <br /><br />Any sounds before the event?<br /><br />Did this come on suddenly. Engine has worked in the past, or did you just get this setup and have had the problem since acquiring it?<br /><br />Assume when it lock up you cannot force it forward or backward?
 

mallen

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Joined
Jun 30, 2005
Messages
18
Re: Engine locks up when warm Cold does fine

Just got the setup.... Haven't been able to do anything with it yet. The guy I bought it off of says he didn't have any problems last year. The only sound is the engine sounding as if it lost a couple of cylinders (no fire that is)then it loses power we slow I back it off and it dies (locks). It has never done it at WOT. I always here the noise back it off and then it dies. Come to think of it by the time I get back there and get the cover off I can push it through a revolution.. thats how quick it frees up. I bought a compression tester a few minutes ago and will let you know the results
 

mallen

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Joined
Jun 30, 2005
Messages
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Re: Engine locks up when warm Cold does fine

OK guys here is the skinny... I have 4 89 psi's. I also have a 70 and a 62 psi. If what Johnson said correct then I have motor replica. Here is the next question? I haven't been inside yet but what are the chances of repairing or are we talking new powerhead time?
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: Engine locks up when warm Cold does fine

Pull the heads and inspect the bores. If scored, you have two choices: 1) rebore and fit new oversize pistons -- i.e. = rebuild. 2) New or rebuilt power head. If the cylinders are not scored, disassemble the power head, inspect everything, measure piston-bore clearances and re-ring if within tolerance. Buy an engine specific service manual so you have all the rebuild info you need. Then before firing the rebuilt engine, figure out why it failed in the first place or you will likely get to do everything over again.
 

mallen

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Joined
Jun 30, 2005
Messages
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Re: Engine locks up when warm Cold does fine

Where can I get an engine specific manual.. Meaning one that doesn't cover mulitiple years correct???? Second is that going to have component location diagrams because I don't even know where the thermostats are at. What do you think I am looking at for the cost of a rebuild if I do all but the over bore myself?
 

mallen

Cadet
Joined
Jun 30, 2005
Messages
18
Re: Engine locks up when warm Cold does fine

don't stop now help me finish this one. The way I see it I have two bad cylinders. Help me make them right.
 
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