Mercruiser 3.0 frozen

flatcatman · May 19, 2011

I just got a 1991 Bayliner Capri 2050 bowrider. While cleaning/checking the boat over, I cannot get the motor to turn over. I pulled the plugs and poured in some Lucas upper cylinder lube to let that soak. The Crankshaft pulley is too close to the front motor mount to be able to get a ratchet on it to turn it. Anyone have any good ideas on how to get the pulley to turn. I'm sure it just needs to soak for a bit then be "powered" loose, but I just can't get anything on it to turn it. I can pry on it against the motor mount, but theres just not enough leverage. Any thoughts?

Fordiesel69 · May 19, 2011

Re: Mercruiser 3.0 frozen

Is there any external parts of the block cracked? Water in oil?

If not, you should pull the engine and properly disassemble & go thru it. Engines CAN be saved if done the proper way. Simply breaking it loose will just buy you a very short time of use. Doing it proper will buy you years of use.

I have restored several snowmobile & car engines that were rusted tight.

flatcatman · May 19, 2011

Re: Mercruiser 3.0 frozen

No water in the oil, and no cracks anywhere that I have found. I plan on rebuilding the motor over the winter when I restore the boat. Just trying to find out what I have to work with.

tschmidty · May 19, 2011

Re: Mercruiser 3.0 frozen

I assume you are turning it from the starter. Are you sure it's the motor and not the outdrive? I'd pull the outdrive (you have to anyway since you need to change the impeller, etc.), remove the plugs, let it soak, remove the distributor and use a tool to turn the oil pump (auto zone and those places will loan it), then try the starter.

flatcatman · May 19, 2011

Re: Mercruiser 3.0 frozen

The starter engages, but can't turn the motor. I'm thinking of making a tool that will fit so I can turn the crank pully. The outdrive has already been pulled (it was in the boat when I got it), I'm working on getting all of the bearings replaced as soon as I know the engine will turn over.

fishrdan · May 19, 2011

Re: Mercruiser 3.0 frozen

Take a bunch of washers, some 1 - 2" long bolts, and bolt a washer stack down to the 3 balancer bolt holes. Hopefully, with the 3 bolts and a long cheater bar, you'll have enough leverage to break the engine loose. Just don't go crazy trying to turn it over or you could shear off one of the bolts,,, would suck to go flying out of the boat and onto the ground. The longer the bolt, the easier it's going to shear off, but the easier it will hold the cheater bar...

Bt Doctur · May 19, 2011

Re: Mercruiser 3.0 frozen

pulling the head will give a better indication of whats wrong.

dingdongs · May 19, 2011

Re: Mercruiser 3.0 frozen

pull drive first as if thats seized engine will not retate either.did you buy the boat seized?have you ever seen it run?if not its best to pull drive ,remove oil,remove top end and starter and all ancillaries and a couple of big beefy guys should be able to lift engine.once head is off you may be able to see if water or a heat seize was the main factor.the costs will now have to be weighed up but if your having to pay labour to anyone may be time for a new engine.

Stevie W · May 20, 2011

Re: Mercruiser 3.0 frozen

What about removing the starter motor and using either a small pry bar or a large flat blade screwdriver put some pressure on the ring gear. It sometimes works better to apply the pressure in in a contra rotation as often the problem is just caused by moisture in the bore creating a slight rust ring pinching the piston rings. The contra rotation takes the rings away from the tight spot.

mrsaundep · May 20, 2011

Re: Mercruiser 3.0 frozen

Flatcatman...

I had exactly the same problem, engine apparently seized as she would not turn over. The starter spun fine when removed. I tried levering the flywheel through the starter mounting hole and then I put bolts in the balancer pulling holes and tried to lever it round, all no go. I pulled the motor out of the boat, and luckily found a core plug had popped out and was trapped between the flywheel and the flywheel cover, that was preventing her from turning over. See photo. After the damaged plug was removed she spun over just fine.

I then fully stripped the engine to check the block etc for cracks as I guess she must have frozen, luckily all is good. I am now rebuilding her, should be as good as new. I hope your as lucky with the cause of your "seized" engine.

slim766 · May 20, 2011

Re: Mercruiser 3.0 frozen

I had the same problem with my 3.0L this spring. It turned out to be a problem with the starter rather than the engine itself. The starter would engage but not turn the engine over. After looking I found corroded contacts in the starter. A little cleaning and it's working just fine. I hope this helps.

Kris

flatcatman · May 22, 2011

Re: Mercruiser 3.0 frozen

UPDATE!!!
The motor is turning over freely now. The outdrive appears that it will be salvageable. Still working on getting the motor to fire. Everything pointed to a bad coil. Replaced the coil, still no spark. Got to playing around with the neutral safety switch and when i jumper across it and make and break the contact while I'm turning the engine over, I have spark. That's the only way I've been able to get spark so far though. As soon as the rain passes by, I'm going to see what happens when I disconnect the switch all together. Any other ideas? And where do I find my engine serial number?

NHGuy · May 22, 2011

Re: Mercruiser 3.0 frozen

There's also a shift interrupt switch that will prevent spark. You need the manual! it will save you time and point you right. Good luck and have fun.

flatcatman · May 22, 2011

Re: Mercruiser 3.0 frozen

How do I get the manual? I don't even know the serial number of the engine or how to find it.

dubs283 · May 22, 2011

Re: Mercruiser 3.0 frozen

the serial number of the engine is either on the plastic flame arrestor cover or the valve cover on a red engine spec tag

there should also be a metal tag rivoted to the engine block just above the starter that has the serial number stamped into it

if you can find no serail/model number info we're gonna have to guess as to which manual you need based on the ignition type and vintage of the boat

flatcatman · May 22, 2011

Re: Mercruiser 3.0 frozen

I'll go look for the metal tag. The plastic cover is broken, and the valve covers don't look like others I have seen of the same model.

flatcatman · May 23, 2011

Re: Mercruiser 3.0 frozen

Well, there's no metal tag on the motor anywhere! There are some numbers stamped in the spark arrestor, but its in the metal of it, not the plastic cover. The boat is a 1991

dubs283 · May 23, 2011

Re: Mercruiser 3.0 frozen

here is a link to download an engine manual for 4 cyl engines starting 1990

http://www.4shared.com/document/B3wzU5Iz/Service_Manual_13.html

its the best bet for ya

flatcatman · May 24, 2011

Re: Mercruiser 3.0 frozen

Thanks Dubs, I'll take a look and see what I can find!

Mercruiser 3.0 frozen

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