3.0 liter mercruiser cooling

[Fish n Ski]

I store my 2003 1954 F+S in a climate controlled garage. (got it last year) I didn't think to drain the water from the engine. After a year I brought it out yesterday to get ready for wakeboarding and the engine would not turn over. I drained the water from the quick disonnect lines - slightly discollored, and finally got the engine free by turning the propeller whil in gear. Engine started but ran ROUGH! Last cylinder nearest outdrive doesn't fire, plug is black. What did I do? Where do I begin in trouble-shooting and repair? Advice?? Boat is otherwise lik new, 75 hours, you could eat off the engine. Thanks, Fish n Ski

 

[indy440]

Re: 3.0 liter mercruiser cooling

i can't imagine why the engine was stuck unless water got inside the cylinders somehow. Also, the starter is going to apply way more torque to the engine than you can by spinning the prop in gear. Maybe you just had a bad spot in the flywheel and the starter wouldn't grab?

Do a compression test. If its good put new spark plugs in.

 

[Fish n Ski]

Re: 3.0 liter mercruiser cooling

Thanks for your reply indy440. Motor was really stuck. Starter motor couldn't begin to turn it over. Took a LOT of push to turn it over with the prop in gear, no plugs in, forward then reverse, then finally engine turned over with starter, put plugs back in and it kinda started. Lots of backifre but couldn't really start until disconnected last sparkplug wire, then it started and ran on three cylinders. Boat had fresh water in coolant sustem, never been in salt water. corrosion? Headgasket? Oil appears clear, of course motor hasn't run long. I'll check compression, get new plugs but this engine ran like a clock all last summer. I can'y imagine all this going wrong while sitting in a 60F shop over winter. Thoughts?

 

[indy440]

Re: 3.0 liter mercruiser cooling

Check you're firing order with the manual, If it will run with one wire disconnected but wont run with it connected then you've got your wires on wrong, which will cause lots of backfiring. If that is correct and you still have the same issue then check the timing. I really think you have your wires on wrong.

It sounds like somehow water or moisture got in the cylinder and rusted the rings to the cylinder bore. This isn't always that big of a deal believe it or not. I've had a few engines (marine, snowmobile, automotive) 2-stroke and 4-stroke get stuck from sitting with moisture and most of the time they run again without much grief. I've also had one or two that were way down on compression after getting it freed up...

Get your plug wire/firing order figured out, then run it on the hose for 30-45 minutes, then do a compression test.

 

[futz]

Re: 3.0 liter mercruiser cooling

me if it were my boat, i would yank the drive off. I would put water to the long hose that connects to the t-stat. Then try to start it, after replacing the plugs with new ones.

 

[Gene70]

Re: 3.0 liter mercruiser cooling

You need to remove the exhaust system and pressure test the riser and the log. You need to remove the cylinder heads and do a valve job. You will find your problem when you remove these parts. You have sticky valves. Sounds like water has been getting into the exhaust manifold and cylinder heads. Be sure to use marine gaskets. You can purchase these at an auto parts store but be sure to ask them for marine gaskets. Feltpro makes marine gaskets.

 

[Howard Sterndrive]

Re: 3.0 liter mercruiser cooling

finally got the engine free by turning the propeller whil in gear.

Black spark plug is not a symptom of hydrolocked engine. It's a symptom of a rich fuel mixture.

Maybe the carb float is stuck and the engine locked on fuel.

 

[TowRoper]

Re: 3.0 liter mercruiser cooling

go with futz and Howard B4 taking it apart! wow.....

 

[Howard Sterndrive]

Re: 3.0 liter mercruiser cooling

finally got the engine free by turning the propeller whil in gear.

I still can't fathom that.

I'd think you'd have to have a 10 foot lever on the prop to turn an engine that wasn't seized. I'd have though an aluminum prop would bend before the engine would roll.

Sounds dangerous too

 

[Bondo]

Re: 3.0 liter mercruiser cooling

What did I do?

Ayuh,... I don't see any signs of Water intrusion,....
I'd sooner think the Problem is what you Haven't done, not what you Did do....

Such as regular Annual Maintanance.....

 

[Fish n Ski]

Re: 3.0 liter mercruiser cooling

Indy440 you were right on! When pulling the plugs initially to get the motor turned over, my son crossed cylinder 3 and 4 when putting them back on. I checked the manual as you said and sure enough ran like a champ after correcting the order. Thanks again. Oh and Howard Sterndrive. You don't need any tool to turn the engine over by turning the prop in forward or reverse. My son and I donned some heavy duty leather gloves and together got it loose. Normally with the plugs out (no compression) there isn't much resistance to turning over.
Fish n Ski

 

[bds85466]

Re: 3.0 liter mercruiser cooling

so it was firing the plugs on an incorrect timing schedule?

 

[ran007]

Re: 3.0 liter mercruiser cooling

Indy440 you were right on! When pulling the plugs initially to get the motor turned over, my son crossed cylinder 3 and 4 when putting them back on. I checked the manual as you said and sure enough ran like a champ after correcting the order. Thanks again. Oh and Howard Sterndrive. You don't need any tool to turn the engine over by turning the prop in forward or reverse. My son and I donned some heavy duty leather gloves and together got it loose. Normally with the plugs out (no compression) there isn't much resistance to turning over.
Fish n Ski

You know I was browsing around and this thread caught my eye. I read the entire first post first, then all the others. I'm no expert on motors, but I just gotta say how stupid people sound when they turn a simple problem into a complex beast.

...Like the guy (A) that told you to rip everything apart and you'll begin finding problems - well HELLO? you're problem will be just that! you've riped everything apart! One guy (B) hit it right on the head with the ignition wires. These are the type of people I wish we had more of on this great planet. Start with simple solutions, and pray to God you don't end up taking your boat to a mechanic like guy (A).

 

[TowRoper]

Re: 3.0 liter mercruiser cooling

you must be guy c lol

 

[indy440]

Re: 3.0 liter mercruiser cooling

i figured that was your problem with the backfiring.

If you have a compressor tester you may want to check it, but if it runs fine and you dont have a tester then forget about it and enjoy whats left of summer...

AND WINTERIZE IT THIS FALL